Bibliografie tematiche / (Photo)stability

Letteratura scientifica selezionata sul tema "(Photo)stability"

Autore: Grafiati

Pubblicato: 8 giugno 2024

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Articoli di riviste sul tema "(Photo)stability":

Schallreuter, Karin U., Jeremy Moore e John M. Wood. "On Photo-Stability of Oxybenzone". Journal of Investigative Dermatology 110, n. 1 (gennaio 1998): 96–97. http://dx.doi.org/10.1038/sj.jid.5602936.

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Santoro, Ettore. "On Photo-Stability of Oxybenzone". Journal of Investigative Dermatology 110, n. 1 (gennaio 1998): 95–96. http://dx.doi.org/10.1046/j.1523-1747.1998.00082.x.

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Abid, Abdul Rahman, Bronisław Marciniak, Tomasz Pędziński e Muhammad Shahid. "Photo-stability and photo-sensitizing characterization of selected sunscreens’ ingredients". Journal of Photochemistry and Photobiology A: Chemistry 332 (gennaio 2017): 241–50. http://dx.doi.org/10.1016/j.jphotochem.2016.08.036.

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Wang, Jian‐Hua, Shao‐Peng Wang, Pavel N. Melentiev, Bin Kang, Jing‐Juan Xu e Hong‐Yuan Chen. "Photo‐stability and Photo‐damage of SPASER Nanoparticles under Nanosecond Pulsed‐laser". Chinese Journal of Chemistry 40, n. 4 (24 dicembre 2021): 507–14. http://dx.doi.org/10.1002/cjoc.202100629.

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LIU, Minghua. "Surfactant Enhancing Photo-Stability of Folic Acid". Acta Physico-Chimica Sinica 35, n. 7 (2019): 663–64. http://dx.doi.org/10.3866/pku.whxb201811042.

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Bulloch, R. H., e J. R. Reynolds. "Photostability in dioxyheterocycle electrochromic polymers". Journal of Materials Chemistry C 4, n. 3 (2016): 603–10. http://dx.doi.org/10.1039/c5tc03536h.

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Pandey, Krishna K., Jayashree e H. C. Nagaveni. "Study of dimensional stability, decay resistance, and light stability of phenylisothiocyanate modified rubberwood". BioResources 4, n. 1 (11 gennaio 2009): 257–67. http://dx.doi.org/10.15376/biores.4.1.257-267.

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Rubber wood (Hevea brasiliensis) was esterfied with phenylisothiocya-nate, and dimensional stability, decay resistance, and photo stability of the modified wood was assessed. The chemically modified wood was characterized by FTIR and CP/MAS 13C NMR spectroscopy. Unmodified and modified samples were exposed to a brown rot (Polyporus meliae) and a white rot (Coriolus versicolor) fungus for 12 weeks. Modified wood samples exhibited good dimensional stability and were very resistant to decay. However, phenylisothiocyanate modification of wood was not effective in decreasing photo-yellowing.

Ruqaya Raad e Mustafa Abdallh. "Surface modification to enhance photo-stability of polymers". GSC Advanced Research and Reviews 11, n. 2 (30 maggio 2022): 080–88. http://dx.doi.org/10.30574/gscarr.2022.11.2.0130.

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Photo-degradation is an irreversible alteration in the chemical, mechanical and physical properties of polymers, these alterations are a result of photon absorption from sunlight. UV-light is considered to be the main factor for initiating photo-degradation process of polymers. To extend the lifetime of polymers, their durability, overall minimization of the rate of photo degradation and protection of polymers against environmental factors, stabilizers are introduced to polymers. In addition, since the interaction of the polymer with its environment occurs mainly at the surface of the polymer, therefore surface modification of polymers is used to enhance the UV photo-stabilization. This method can also provide a more durable, weather resistant and photo-stable polymers.

Fahmy, Hassnaa M., Nabel A. Negm, Ahmed H. M. Elwahy e Maram T. H. Abou Kana. "Laser induced fluorescence, photo-physical parameters and photo-stability of new fluorescein derivatives". Journal of Molecular Liquids 229 (marzo 2017): 31–44. http://dx.doi.org/10.1016/j.molliq.2016.12.047.

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Chen, Shaoyu, Chaoxia Wang, Yunjie Yin e Kunlin Chen. "Synthesis of photo-responsive azobenzene molecules with different hydrophobic chain length for controlling foam stability". RSC Advances 6, n. 65 (2016): 60138–44. http://dx.doi.org/10.1039/c6ra06459k.

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Più fonti

Tesi sul tema "(Photo)stability":

Razzell, Hollis Joseph. "Understanding morphology and photo-stability of organic solar cells via advanced structural probes". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/32271.

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The development of organic solar cells as a novel form of renewable energy has been driven by their potential for low-cost, large-scale fabrication though the solution-processing of semiconducting polymers and small molecules. Certified power conversion efficiencies have reached 13% as of 2016 thanks to the development of new donor-acceptor molecules, but the efficiency of any given device is still highly sensitive to the morphology that these materials adopt during deposition. It is essential that morphology is characterized thoroughly in order to establish the relationships between molecular structure, morphological properties and device performance; in order to maximise efficiency and make organic solar cells an economically competitive source of renewable energy. In this thesis, several spectroscopic techniques are used to probe the impact of various processing parameters on the molecular order, crystallinity and phase separation of polymer:fullerene blends. For the model blend system P3HT:PCBM, P3HT molecular order can be measured by resonant Raman spectroscopy, and PCBM is found to dissolve in the amorphous domains of the semi-crystalline polymer up to a miscibility limit of 25 %wt, above which it can only be accommodated by increased disorder. In situ annealing demonstrates that when heated above a glass transition temperature of ~50C, disordered blends separate into purer domains of high molecular order that correlate well to improved charge transport and efficiency for thermally annealed devices. Raman spectroscopy is also used to probe the stability of the high-efficiency PTB7:PC70BM blend. Photo-oxidation of PTB7 was found to induce specific vibrational changes that correlate to formation of a hydroxyl group on the benzodithiophene unit. In situ experiments reveal that hydroxylation precedes the loss of chromophores that results in deterioration of device performance, and is accelerated by blending with PC70BM. Understanding the impact of morphology on charge extraction from the active layer requires the selective probing of interfacial properties at the top and bottom of the organic film, which we demonstrate using SERS. For both a polymer:fullerene blend (PTB7:PC70BM) and a polymer:polymer blend (P3HT:F8TBT), spin-coated films exhibit interfacial compositions different from that of the bulk film and favourable to charge extraction from inverted device architectures, but can be modified by pre- or post-annealing treatments. Finally, we investigated the morphology of a novel low band-gap polymer, a tellurium analogue of polythiophene, in order to understand the impact of the heavy atom on chain planarity and polymer crystallinity. The Raman spectrum of P3ATe exhibited a much stronger sensitivity to molecular order, which was highly dependent on the length and linearity of the alkyl side chain, but there was no clear morphological reason why P3ATe reportedly performs poorly compared to P3HT, despite the superior absorption of its smaller band-gap.

Mouri, Shinichiro. "Dynamical properties of photo-induced spin conversion in the spin crossover complex with multi-stability". 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/124406.

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Zhang, Chaohong [Verfasser], e Christoph [Gutachter] Brabec. "Influence of Microstructure on Thermo- and Photo-stability in Organic Bulk-heterojunction Solar Cell / Chaohong Zhang ; Gutachter: Christoph Brabec". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2018. http://d-nb.info/1150967692/34.

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Mabrouk, Salima. "Synthèse par voie colloïdale et étude des propriétés optiques et structurales de nanocristaux ternaires ZnSeS dopés". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0169.

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Depuis quelques années, les QDs ternaires ont connu un développement exponentiel grâce à leurs propriétés, notamment leur photoluminescence, qui peut non seulement être contrôlée par leur taille mais également par leur composition. Dans le cadre de cette thèse, nous avons développé une nouvelle méthode de synthèse « verte » en milieu aqueux de QDs ternaires ZnSeS dopés et nous avons étudié l'effet de la variation du dopant (Mn2+, Cu2+ou Cu2+/Al3+) ainsi que de sa localisation (dans le cœur ou dans la coquille) sur leurs propriétés optiques et structurales. La première partie de ce travail décrit la synthèse des QDs ternaires cœur ZnSeS:Mn et cœur/coquille ZnSeS:Mn/ZnS en utilisant le 2-MPA comme ligand. Les résultats obtenus montrent que ces nanocristaux peuvent être préparés avec des rendements quantiques de 22 et 41%, respectivement. Ces QDs ont montré une excellente photostabilité sous irradiation UV et peuvent facilement être transférés en phase organique à l'aide du ligand hydrophobe octanethiol et cela sans altération de leurs propriétés optiques. Par la suite, des QDs cœur/coquille/coquille ZnSeS/ZnS:Cu/ZnS pour lesquels le dopant Cu est introduit dans la première coquille ont été préparés en utilisant le 3-MPA comme ligand. Une excellente (photo)stabilité en présence d'air et d'oxygène ont été observés. Les QDs cœur/coquille/coquille ZnSeS/ZnS:Cu/ZnS ont un rendement quantique de photoluminescence de 20% et ont été utilisés comme sondes photoluminescentes pour la détection des ions Pb2+ en milieu aqueux. Une extinction sélective de l'émission de photoluminescence en présence des ions Pb2+ a été observée. Enfin, des QDs co-dopés Cu et Al, ZnSeS/ZnS:Cu/ZnS:Al/ZnS (première coquille dopée avec Cu2+ et deuxième coquille dopée avec Al3+) ont été préparés. Le co-dopage permet l'amélioration des propriétés optiques, notamment du rendement quantique (jusqu'à 32%) ainsi que de la durée de vie de photoluminescence des QDs dopés Cu
In recent years, ternary QDs have experienced an exponential development thanks to their properties, especially their photoluminescence, which can be controlled not only by their size but also by their composition. As part of this thesis, we developed a new "green" synthesis in aqueous media of ZnSeS-doped ternary QDs and we studied the effect of the variation of the dopant (Mn2+, Cu2+, or Cu2+/Al3+) as well as its localization (in the core or in the shell) on their optical and structural properties. The first part of this work describes the synthesis of ZnSeS:Mn ternary QDs and ZnSeS:Mn/ZnS core/shell using 2-MPA as a ligand. The results obtained show that these nanocrystals can be prepared with quantum yields of 22% and 41%, respectively. These QDs have shown excellent photostability under UV irradiation and can easily be transferred to the organic phase using the hydrophobic octanethiol ligand without altering their optical properties. Subsequently, core/shell ZnSeS/ZnS:Cu/ZnS QDs for which the Cu dopant is introduced into the first shell were prepared using 3-MPA as a ligand. Excellent (photo)stability in the presence of air and oxygen was observed. ZnSeS/ZnS:Cu/ZnS core/shell QDs have a 20% photoluminescence quantum yield and have been used as photoluminescent probes for the detection of Pb2+ ions in aqueous media. A selective extinction of the photoluminescence emission in the presence of Pb2+ ions was observed. Finally, Cu and Al co-doped QDs, ZnSeS/ZnS:Cu/ZnS:Al/ZnS (first shell doped with Cu2+ and second shell doped with Al3+) were prepared. Co-doping allows the improvement of the optical properties, including quantum efficiency (up to 32%) as well as the photoluminescence lifetime of Cu-doped QDs

Hansson, Rickard. "Morphology and material stability in polymer solar cells". Licentiate thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37843.

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Polymer solar cells are promising in that they are inexpensive to produce, and due to their mechanical flexibility have the potential for use in applications not possible for more traditional types of solar cells. The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime of polymer solar cells has become at least as important as improving the efficiency. In this thesis, the relation between morphology and solar cell performance is studied, and the material stability for blend films of the thiophene-quinoxaline copolymer TQ1 and the fullerene derivatives PCBM and PC70BM. Atomic force microscopy (AFM) and scanning transmission X-ray microscopy (STXM) are used to investigate the lateral morphology, secondary ion mass spectrometry (SIMS) to measure the vertical morphology and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to determine the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed TQ1 surface enrichment does not affect the performance. Changes to the unoccupied molecular orbitals as a result of illumination in ambient air are observed by NEXAFS spectroscopy for PCBM, but not for TQ1. The NEXAFS spectrum of PCBM in a blend with TQ1 changes more than that of pristine PCBM. Solar cells in which the active layer has been illuminated in air prior to the deposition of the top electrode exhibit greatly reduced electrical performance. The valence band and absorption spectrum of TQ1 is affected by illumination in air, but the effects are not large enough to account for losses in solar cell performance, which are mainly attributed to PCBM degradation at the active layer surface.
The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime has become at least as important as improving the efficiency for polymer solar cells to become a viable technology. In this work, the relation between morphology and solar cell performance is studied as well as the material stability for polymer:fullerene blend films. A combination of microscopic and spectroscopic methods is used to investigate the lateral and vertical morphology as well as the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed surface enrichment of polymer does not affect the performance. Changes to the unoccupied molecular states as a result of illumination in ambient air are observed for the fullerene, but not for the polymer, and fullerenes in a blend change more than pristine fullerenes. Solar cells in which the active layer has been illuminated exhibit greatly reduced electrical performance, mainly attributed to fullerene degradation at the active layer surface.

Paper 2 ingick som manuskript i avhandlingen. Nu publicerad.

Shehayeb, Sanaa. "Récepteur solaire photo-thermique obtenu par électrophorèse de nanoparticules à propriété optique sélective". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT195/document.

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La production d'eau chaude via des capteurs solaires photothermiques est une technique en expansion qui permettra de limiter l'utilisation des sources conventionnelles d’énergie (combustibles fossiles, nucléaire…). Le cuivre noir (CuO) s’avère être un matériau possédant des propriétés optiques sélectives intéressantes pour cette application. Ainsi, son utilisation au sein d’un absorbeur sous forme d’un matériau « tandem » est une solution envisagée. Le défi que nous avons tenté de relever au cours de ce travail, a été de réaliser ce type de matériau par dépôt électrophorétique (EPD) de nanoparticules de CuO déposé sur un substrat métallique de type wafer de silicium recouvert de platine ou d’or. Ce substrat « modèle » a été utilisé dans un premier temps, car il facilite la mise en œuvre de techniques de caractérisation telles que l’analyse par diffraction X en incidence rasante (GIXRD) ou l’analyse en coupe par microscopie électronique à balayage. Pour ce faire, la stabilisation de la suspension colloïdale de CuO, qui est une condition sine qua non pour la réalisation d’un dépôt électrophorétique, a été étudiée dans un solvant organique tel que l'isopropanol par ajout de Mg(NO3)2, ainsi que dans l’eau en utilisant du polyethylenimine comme dispersant. Ces deux adjuvants agissent comme des agents stabilisants et apportent aux nanoparticules une charge positive ce qui permet la réalisation d'un EPD cathodique. Afin d’optimiser la formulation des suspensions, la stabilité colloïdale en fonction de la teneur en stabilisant a été étudiée avant tout dépôt, par diffusion dynamique de la lumière (DLS) couplée à la vélocimétrie laser à effet Doppler.Différents revêtements contenant du CuO ont été obtenus en faisant varier les paramètres classiques de l’EPD (temps de dépôt, champ électrique, concentration en nanoparticules) pour pouvoir contrôler l'épaisseur finale et la morphologie. Par conséquent, la sélectivité optique et le rendement du tandem résultants peuvent être optimisés en jouant sur l’ensemble de ces paramètres. Des dépôts homogènes ont été obtenus pour [CuO] =5x10-4 g/cm3 pour les deux milieux. Les meilleures conditions sont 50 V.cm-1// 30mn pour la suspension d'IPA et 2 V.cm-1 // 120 mn pour la suspension en milieu aqueux. La composition et l'épaisseur des dépôts sont analysées par GIXRD, et par microscopie électronique (SEM-EDS). Pour les conditions optimisées, les matériaux tandem obtenus à partir de la suspension d'IPA+CuO possèdent une densité de 1.69 g/cm3 avec une grande rugosité. Au contraire, des surfaces homogènes et régulières sont obtenues en milieu aqueux et les dépôts présentent une densité beaucoup plus élevée d’environ 5.7 g/cm3.L’absorptance (α) et l’émittance (ԑ) ont été calculées à partir des spectres de réflectance de l'UV-VIS-NIR et de l’Infrarouge lointain, respectivement. L'efficacité (ƞ) du revêtement tandem obtenu en milieu aqueux est comprise entre 0.8-0.87 tandis qu’elle est seulement de 0.7 dans l’IPA. De plus, la faisabilité de l’EPD sur d’autres substrats métalliques plus conventionnels en vue d’une application (acier, aluminium, cuivre) a été explorée. L'efficacité des dépôts a pu être améliorée par des post-traitements de deux types. D’une part, en pyrolysant à 400°C sous atmosphère inerte le polymère (PEI) incorporé dans le revêtement. Le carbone résiduel obtenu à l’issue de cette pyrolyse a permis d’augmenter l’absorbance. D’autre part, en déposant sur la surface des revêtements une couche de nanoparticules de SiO2 qui joue le rôle de couche anti-réflexion et permet également de protéger la surface. Les deux voies ont été réalisées avec succès et le rendement le plus élevé obtenu pour ces revêtements est de 0.9
The production of hot water by using efficient photothermal solar collectors is growing in importance to limit the use of fossil fuels. Black copper (CuO) has proved to be one of the viable solar-selective coatings owing to its nearly intrinsic properties. The formation of a tandem absorber based on CuO thin film deposited onto a highly IR reflecting metallic substrate is processed by electrophoretic deposition (EPD).In this way, the stabilization of a CuO colloidal suspension is studied previously by adding Mg(NO3)2 in isopropanol (IPA) or polyethylenimine (PEI) in water suspension. Both acts as positively charging agents and allow the realisation of a cathodic EPD. The colloidal stability as a function of the stabilizing agent content is studied prior to EPD, by dynamic light scattering (DLS) coupled with laser doppler velocimetry.CuO tandem absorbers are obtained by varying different EPD parameters to control the final thickness and also the morphology. Consequently, the optical selectivity of the tandem material is tuned and optimized. The deposition yield is compared relative to the different applied voltage range, deposition time and nanoparticle concentrations. Homogeneous deposits are obtained for [CuO]=5x10-4 g/cm3 from both suspensions. The optimum applied voltage is found to be 50 V.cm-1 for IPA suspension and 2 V.cm-1 for H2O suspension, for deposition times of 30 mins and 120 mins, respectively. The composition and the thickness of the coatings are analysed by Grazing Incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and the density is obtained from energy-dispersive X-ray spectroscopy (EDX). For the previously mentioned optimized conditions, CuO tandem absorbers derived from IPA suspension possess a density of 1.69 g/cm3 with high surface roughness. In contrast, homogeneous and regular surfaces is obtained from water suspensions having a higher density of 5.7 g/cm3.Moreover, absorptance (α) and emittance (ԑ) are calculated from the reflectance spectra of the UV-Vis-NIR and the Fourier transform InfraRed (FTIR) spectroscopy, respectively. α and ԑ were combined to determine the efficiency (ƞ) of the tandem material. Tandems obtained from water suspension has ƞ=0.8 -0.87 while from IPA ƞ=0.7. Besides, the applicability of this EPD is checked by performing other deposit of CuO on metallic substrates of different types.CuO tandems obtained from water suspensions are clearly more prominent to be used as solar selective tandem absorbers due to the high calculated ƞ value reported. The efficiency of such selective tandem absorbers was further enhanced by carbonization (pyrolysis under inert atmosphere) of the polymer (PEI) embedded in the coating. Otherwise, a thin film of SiO2 nanoparticles was deposited at the surface of the selective tandem absorbers to protect them. Both routes were successfully processed and proved to raise ƞ to 0.9

Peng, Yong. "Hybrid Lead Perovskites as Photocatalysts and Materials for Photo- and Electrocatalytic N2 Reduction". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/171731.

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Tesis por compendio
[ES] La conversión de energía solar a productos químicos se considera una de las estrategias más viables para abordar los problemas derivados del uso masivo de combustibles fósiles y la excesiva emisión antropogénica de CO2. En catálisis asistida con luz, incluida la fotocatálisis y la catálisis fototérmica, el punto clave es el desarrollo de fotocatalizadores eficientes y robustos que puedan utilizar al máximo la energía solar y que sean lo suficientemente estables como para su comercialización. Los materiales basados en perovskitas híbridas orgánicas-inorgánicas han revolucionado el campo de la fotovoltaica en la última década, alcanzando una eficiencia de conversión de luz solar del 23%. Dado que los campos de la fotocatálisis y la fotovoltaica comparten procesos comunes, se abre la posibilidad de aplicación de estos materiales en fotocatálisis. Con el objetivo de confirmar esta posible aplicación de las perovskitas híbridas en fotocatálisis, en esta Tesis Doctoral, se han sintetizado nuevos materiales híbridos de perovskita con el objetivo de mejorar su estabilidad frente a la humedad aprovechando la gran variedad de ligandos orgánicos disponibles, que además pueden ser usados para promover modificaciones superficiales capaces de ajustar las propiedades hidrofílicas / hidrofóbicas. La actividad fotocatalítica de estos nuevos materiales de perovskita se ha estudiado en reacciones modelo para confirmar su estabilidad en las condiciones de reacción. Por otro lado, la reacción de fijación de nitrógeno fotoasistida también ha sido estudiada en detalle en esta Tesis Doctoral. Por un lado, se han sintetizado, caracterizado y testado nuevos complejos organometálicos como foto- y electrocatalizadores homogéneos para esta reacción. Estos han demostrado ser capaces de activar la molécula de dinitrógeno bajo un potencial electroquímico de reducción para formar amoníaco. Por otro lado, se han preparado nanopartículas de rutenio depositadas sobre un material de perovskita a base de titanato como fotocatalizador heterogéneo para la producción de amoniaco en flujo continuo. Además, se ha demostrado que la incorporación de metales alcalinos a este fotocatalizador puede potenciar su actividad fotocatalítica en esta reacción. Así, este material compuesto ha demostrado estar entre los fotocatalizadores más eficientes del estado del arte en la actualidad para esta reacción demostrando además una su elevada estabilidad en las condiciones de reacción.
[CA] La conversió d'energia solar en productes químics es considera una de les estratègies més viables per abordar els problemes derivats de l'ús massiu de combustibles fòssils i l'excessiva emissió antropogènica de CO2. En catàlisi assistida amb llum, inclosa la fotocatàlisi i la catàlisi fototèrmica, el punt clau és el desenvolupament de fotocatalitzadors eficients i robustos que puguen utilitzar al màxim l'energia solar i que siguen prou estables com per a la seva comercialització. Els materials basats en perovskites híbrides orgàniques-inorgàniques han revolucionat el camp de la fotovoltaica en l'última dècada, aconseguint una eficiència de conversió de llum solar del 23%. Atès que els camps de la fotocatàlisi i la fotovoltaica comparteixen processos comuns, s'obre la possibilitat d'aplicació d'aquests materials en fotocatàlisi. Amb l'objectiu de confirmar aquesta possible aplicació de les perovskites híbrides en fotocatàlisi, en aquesta tesi doctoral, s'han sintetitzat nous materials híbrids de perovskita amb l'objectiu de millorar la seva estabilitat enfront de la humitat aprofitant la gran varietat de lligands orgànics disponibles, que amés poden ser usats per a promoure modificacions superficials capaços d'ajustar les propietats hidrofíliques / hidrofòbiques. L'activitat fotocatalítica d'aquests nous materials de perovskita s'ha estudiat en reaccions model per confirmar la seva estabilitat en les condicions de reacció. D'altra banda, la reacció de fixació de nitrogen fotoassistida també ha sigut estudiada en detall en aquesta tesi doctoral. D'una banda, s'han sintetitzat, caracteritzat i testat nous complexos organometàl·lics com foto- i electrocatalitzadors homogenis per a aquesta reacció. Aquests han demostrat ser capaços d'activar la molècula de dinitrogen sota un potencial electroquímic de reducció per formar amoníac. D'altra banda, s'han preparat nanopartícules de ruteni depositades sobre un material de perovskita a força de titanat com fotocatalitzador heterogeni per a la producció d'amoníac en flux continu. A més, s'ha demostrat que la incorporació de metalls alcalins a aquest fotocatalitzador pot potenciar la seva activitat fotocatalítica en aquesta reacció. Així, aquest material compost ha demostrat estar entre els fotocatalitzadors més eficients de l'estat de l'art actualment per a aquesta reacció seva demostrant amés una elevada estabilitat en les condicions de reacció.
[EN] Solar energy to chemicals conversion is regarded to be one of the most plausible strategies addressing the issues of fossil fuel crisis and excessive anthropogenic CO2 emission. For photo-assisted catalysis, including photocatalysis and photothermal catalysis, the key point is the development of efficient and robust photocatalysts that can efficiently utilize the solar energy as well as they are stable enough that meets the requirements for commercialization. Hybrid organic-inorganic perovskites have revolutionized the photovoltaic field in the last decade, reaching a certified sunlight conversion efficiency of 20 %. Since photocatalysis and photovoltaics share common processes, the application of these materials in photocatalysis would be possible. In this Doctoral Thesis, novel hybrid perovskite materials have been synthesized with the aim to improve their stability against moisture by taking advantage large variety of the available organic ligand, which can promote surface modifications capable to adjust the hydrophilic/hydrophobic properties. Additionally, the photocatalytic activity of these novel perovskite materials has been studied in model reactions in order to confirm their stability under reaction conditions. On the other hand, the photo-assisted nitrogen fixation reaction has been also studied in detail in this Doctoral Thesis. on one hand, new organometallic complexes have been synthetized, characterized and tested as homogeneous photo and electrocatalysts for this reaction. They have been demonstrated to be able to activate dinitrogen molecule under electrochemical cathodic potentials to form ammonia. On the other hand, ruthenium nanoparticles deposited on a titanate-based perovskite material have been prepared and tested as heterogeneous photocatalyst for ammonia production in continuous flow. Moreover, it has been demonstrated that the addition of alkali metals to this photocatalyst can boost the photocatalytic activity of this reaction. Thus, this composite material has demonstrated to be among the most efficient photocatalysts in the current state-of-the art for this reaction, as well as very stable under reaction conditions. Considering the large industrial importance of N2 fixation and the mild conditions of pressure and temperature used in the present study, the results of the photo-assisted N2 hydrogenation to ammonia can have a large impact in the area.
Peng, Y. (2021). Hybrid Lead Perovskites as Photocatalysts and Materials for Photo- and Electrocatalytic N2 Reduction [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171731
TESIS
Compendio

Huang, Shang-Chieh, e 黃尚頡. "Investigation of photo-stability and photo-oxidation mechanism for colloidal quantum dots". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/jyx729.

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Yu, Weilai. "Stability of Photo-Electrochemical Interface for Solar Fuels". Thesis, 2021. https://thesis.library.caltech.edu/14107/1/202104_Weilai_Thesis_Final.pdf.

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Photoelectrochemical (PEC) water splitting is a promising approach to convert renewable solar energy to clean hydrogen (H₂) fuels in one simple step. Although Ⅲ-Ⅴ semiconductors are attractive candidates as light-absorbers in tandem solar-fuel devices, their long-term stability for the hydrogen-evolution reaction (HER) in either acidic or alkaline aqueous electrolytes needs to be established. Chapter 2-5 of this thesis first aims at revealing the underlying corrosion chemistry for a variety of Ⅲ-Ⅴ semiconductors specifically under the HER conditions, offering a rational understanding towards the stability of semiconductor photoelectrode.

In Chapter 2, we start from p-InP and reveal its susceptibility to cathodic photocorrosion forming metallic In⁰, which however can be completely mitigated by the presence of Pt catalyst due to kinetic stabilization. We also show that the resulting PEC performance of p-InP/Pt electrodes is sensitive to the changes in surface stoichiometry, whereas an InO_x-rich surface developed in KOH caused a substantial degradation in the current density-potential (J-E) behavior. In Chapter 3, we discovered that a non-stoichiometric and As⁰-rich surface of p-GaAs, resulting from a galvanic corrosion by Pt, led to mid-gap surface states as well as a complete loss in photoactivity. In Chapter 4-5, we demonstrate similar kinetic stabilization applied to both p-InGaP₂/Pt and pn⁺-InGaP₂/Pt photocathodes for the HER at both pH 0 and pH 14. Additionally, we found that the corrosion of underlying GaAs substrates for the pn⁺-InGaP₂/Pt photocathodes at positive potentials caused damage of structural integrity as well as instability in electrode performance. Altogether these works underscore the mutual dependence of the physical and electrochemical stability of semiconductor photoelectrodes during the HER, which also need to be considered separately. Moreover, both catalytic kinetics and surface stoichiometry are crucial factors for defining long-term corrosion chemistry for semiconductor photoelectrode.

In Chapter 6-7, we further explore solar fuels beyond H₂, namely electrochemical N₂-to-NH₃ conversion. We first establish a new analytical method to isotopically quantify the concentrations of ¹⁵NH₃ in aqueous solutions with a high sensitivity and a low limit-of-detection of <1 μM. Further we applied this advanced method to rigorously verify the electrocatalytic activity of a CoMo electrode for reducing N₂(g) to NH₃. We show that the additional ammonia detected in electrolyte was instead attributed to the corrosion of N impurities present in the CoMo electrode under cathodic bias, thus giving false positive results. These works emphasize the importance of both rigorous product analysis and experiment design in further catalyst development.

Kuo, Yang-Kuao, e 郭養國. "The Stability Control of Semiconductor Photo Lithography in Nano Size". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/24083135967809487005.

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博士
國立交通大學
材料科學與工程系所
93
A new reticle is designed that takes advantage of the high value of thermal conductivity of diamond to add a layer of diamond film to the bottom of traditional pellicle-reticle; that is, the new reticle replaces the pellicle with a diamond material. This method may help maintain the future manufacturing process of photo-lithography below 35 nm and can improve the problem of slightly out of shape reticle caused by the long-term effects of light and thermal energy. Exposure dose is one of the most important factors that affects CD (Critical Dimension) bar since it can change the dimension of line-width and white wall. In this work, both line-width and white wall present a linear relationship ( >0.85) with respect to the exposure dose. However, too high or too low of exposure dose would impose the instability of line-width. The reason for exposure dose to affect CD bar is that when absorbing high energy the photo-resist (PR) can produce more severely neutralized reaction as it in contact with developer. Therefore, the higher the exposure dose the smaller is the line-width. Also, CD bar would reveal inhomogeneous phenomenon caused by absorbing high energy via the edge of PR. Due to this reason, increasing the exposure dose intentionally is not an appropriate method to obtain a smaller CD bar. When it comes to using exposure energy to obtain the desirable CD, PR capable of being exposed with higher energy should be considered. If it becomes necessary to obtain much smaller line width, then it is necessary to use PR of better resolution in conjunction with a light source containing a much lower wavelength. But, higher exposure dose would cause the bottom of PR to absorb more reflective energy and make white wall become smaller. On the contrary, if exposure dose becomes too low, PR would not form a pattern due to the fact that the absorption of exposure energy by PR is not strong enough to produce a neutralized reaction when in contact with TMAH (Tetramethylammonium Hydroxide).

Libri sul tema "(Photo)stability":

Schuett-Hames, Joanne. Germany Creek photo points and channel stability evaluation, 1990-2000. Olympia, Wash: Washington State Dept. of Ecology, Southwest Regional Office, Water Quality Program, 2000.

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Pozhidaeva, Nina. Reversible photo-control of peptide helix content: Adjusting thermal stability of the cis state. 2004.

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ALBINI, A., e E. FASINI. DRUGS:PHOTOCHEMISTRY AND PHOTO (Special Publications). Royal Society of Chemistry, 1998.

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Capitoli di libri sul tema "(Photo)stability":

YAN, HOH-JIEAR, e ELI M. PEARCE. "Thermal and Photo Stability of Polyarylates". In ACS Symposium Series, 209–23. Washington, D.C.: American Chemical Society, 1985. http://dx.doi.org/10.1021/bk-1985-0282.ch018.

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Im, Seongil, Youn-Gyoung Chang e Jae Kim. "Device Stability and Photo-Excited Charge-Collection Spectroscopy". In SpringerBriefs in Physics, 1–16. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6392-0_1.

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Sandford, Scott A., Partha P. Bera, Timothy J. Lee, Christopher K. Materese e Michel Nuevo. "Photosynthesis and Photo-Stability of Nucleic Acids in Prebiotic Extraterrestrial Environments". In Photoinduced Phenomena in Nucleic Acids II, 123–64. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/128_2013_499.

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Aht-Ong, Duangdao, Chiravoot Pechyen e Duangduen Atong. "Evaluation of the Influence of Additives on the Mechanical Properties and Photo-Stability of Glass Fiber Reinforced Epoxy Pipes Using Central Composite Design". In Advanced Materials Research, 349–52. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-463-4.349.

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Sumino, Ken-ichi, Kazuo Asuka, Boping Liu, Masayuki Yamaguchi, Minoru Terano, Takanobu Kawamura e Koh-hei Nitta. "Influence of polymer morphology on photo-stability of polypropylene/SiO2 nanocomposites". In Studies in Surface Science and Catalysis, 229–32. Elsevier, 2006. http://dx.doi.org/10.1016/s0167-2991(06)80463-5.

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Chandran, Senthilkumar, e Srinivasan Manikam. "Optical Properties of Single Crystals". In Optoelectronics. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95607.

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Nonlinear optical crystals plays important role in the field of photo electronics, optical communication, optical modulators, laser spectroscopy, frequency conversion and so on. Semi-organic crystals exhibit high NLO response, thermal stability, laser damage threshold, mechanical stability, wide optical window transmittance and structural diversity. Combinations of inorganic and organic molecules yield the semi-organic crystals. Based on its structural diversity it’s classified into three categories. In this chapter explains various kinds of semi-organic crystals and their optical, thermal, mechanical, laser damage threshold value and NLO properties and also explains the importance of these crystals in the field of optoelectronics, frequency conversion and other optical applications.

Ielo, I., A. M. Cancelliere, A. Arrigo e G. La Ganga. "Metal-based chromophores for photochemical water oxidation". In Photochemistry, 384–409. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781837672301-00384.

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The energy emergency is a severe criticality for the continuous growth of the world population. In this context, there are multiple demands to produce sustainable and carbon-neutral energy capable of meeting the needs of future generations, such as the production of systems for artificial photosynthesis (AP). Photosensitizers (PS) play a crucial role in light absorption and charge separation for AP materials, when suitably-designed for obtaining excellent tunability and performance. This review discusses the studies of the last 10 years on the synthesis of efficient and performing chromophores based on metal complexes for the photo-oxidation of water. In particular, photosensitizers in homogeneous and heterogeneous phase catalytic systems are discussed, whose design aimed to improve the understanding of the photo-oxidative mechanisms and promote higher efficiency and stability of photosynthetic systems. Recent advances in dyad and multicomponent systems both in homogeneous phases and when incorporated into polymeric matrices for heterogeneous catalysis are reviewed. Finally, the significant progress in developing highly performing photoanodes are discussed. Indeed, by varying the distance of the PS from the semiconductor surface and the distance from the catalyst (C), it was possible to study different methods and molecular approaches in the construction of photoanodes for dye-sensitized photoelectrosynthetic cells (DSPEC).

Juvekar, Vinayak, e Hwan Myung Kim. "Two-photon Fluorescent Probes". In Fluorescent Chemosensors, 106–23. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/9781839167324-00106.

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Two-photon microscopy (TPM) is an indispensable bioimaging tool. TPM, which uses photons of a near-infrared wavelength as an excitation source for fluorophores, can result in deeper tissue images, which can potentially be measured beyond a depth of 1000 µm with relative stability in biological systems. With continuous development in deep-tissue optical microscopy and improvements in imaging algorithms, TPM is gaining immense support in biomedical applications. Furthermore, it has propelled the continuous development of appropriate two-photon (TP) probes with improved sensitivities for measuring target analytes in biological specimens. In this chapter, the photo-physiological process, basic TP probe design strategies, and representative TP sensors of TPM that researchers have reported are presented to provide significant information regarding specific targets in biological systems.

Natesan, Subramanian, Nidhi Singh, Victor Hmingthansanga, Pallab Datta, Sai Hanuman Sagar Boddu e V. Ravichandiran. "Nanoemulsions for the Delivery of Anti-Hypertensive Drugs". In Handbook of Research on Nanoemulsion Applications in Agriculture, Food, Health, and Biomedical Sciences, 378–400. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-8378-4.ch017.

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Hypertension refers to an increase in the arterial blood pressure. Most commonly used antihypertensive drugs are available in conventional dosage forms as it offers superior patient compliance. A majority of anti-hypertensive drugs pose bioavailability issues as they belong to BCS class II and BCS class IV categories with poor solubility profile and rate limiting dissolution. Emerging drug delivery technologies like nanoemulsion are found to be promising and safer alternatives for the delivery of anti-hypertensive drugs. Nanoemulsion gained more attention due to favourable properties such as small size, good physical stability, rapid action, drug targeting, prevents photo-degradation, and improved bioavailability. This chapter highlights various aspects of hypertension including its pathophysiology and potential approaches to combat high blood pressure. In addition, the authors thoroughly discussed nanoemulsions and their utility in the oral delivery of anti-hypertensive drugs.

Cetindere, Seda. "BODIPY Dyes in Solar Energy". In Eco-Friendly and Agile Energy Strategies and Policy Development, 119–42. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-9502-2.ch006.

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Solar energy shows great potential in the future energy market due to its essentially unlimited supply and renewable, cheap, and clean nature. Among the third-generation solar technologies that are able to harvest light and convert it to electricity are dye-sensitized solar cells (DSSCs), organic solar cells (OSCs), and inorganic-organic hybrid solar cells also known as perovskite solar cells (PSCs). Among the various organic dyes, BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) dyes have been recognized as promising candidates for solar cells due to their intrinsic advantages such as sharp and strong absorption near 500 nm, which is leading to efficient light-harvesting capability, diverse modification on the core structure at all positions and with any desired functionality, long excited state lifetimes, excellent photo-stability, and good solubility in organic solvents. This chapter will focuse on studies of BODIPY dyes in solar energy technology.

Atti di convegni sul tema "(Photo)stability":

Bar-Yam, Y., J. D. Joannopoulos e D. Adler. "Photo-induced degradation and stability in semiconductor devices". In AIP Conference Proceedings Volume 157. AIP, 1987. http://dx.doi.org/10.1063/1.36487.

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Sinha, Abhishek Kumar, e Amita Amita. "Transient Stability Improvement of Grid Using Photo-Voltaic Solar Farm". In 2018 International Conference on Intelligent Circuits and Systems (ICICS). IEEE, 2018. http://dx.doi.org/10.1109/icics.2018.00081.

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Shi, Yongqiang, David J. Olson, James H. Bechtel, Srinath Kalluri, William H. Steier, Wenshen Wang, Datong Chen e Harold R. Fetterman. "Photo excitation stability and bias voltage stability of electro-optic polymer modulators for broadband analog transmission systems". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.wb.8.

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Broadband analog transmitters are an important part of many information delivery systems. Nonlinear optical (NLO) polymer devices have shown a great potential of playing a major role in ultra-wide bandwidth analog transmission systems due to the low dielectric constant, flexibility of processing, compatibility with semiconductor technology, and high nonlinearities. The general requirements for polymer modulators used in an externally modulated broadband transmission system were briefly discussed previously.[1] In this summary, we will focus on two practical issues for polymer modulators used in an externally modulated analog transmission system: the photo excitation stability and the quadrature bias voltage stability of electro-optic( EO) polymer modulators. The photo excitation stability is directly related to the signal-to-noise ratio of the analog signal link, device life-time, and processing conditions. The bias voltage stability will affect the fidelity of the transmitted analog signal. Using a thermally crosslinkable polyurethane with Disperse Red 19 side groups(PUR-DR19), we have tested the performance and the stability of EO polymer devices.

Abbas, Sikandar, e Linda Peteanu. "Effects of plasmonic substrates on the photo-stability of organic polymer". In SPIE Nanoscience + Engineering, a cura di Artem A. Bakulin, Robert Lovrincic e Natalie Banerji. SPIE, 2016. http://dx.doi.org/10.1117/12.2238261.

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Kusevic, Maja, Arto Maaninen, Jussi Hiltunen, Marianne Hiltunen, Jarkko Tuominen e Pentti Karioja. "Photo-crosslinkable hybrid material with improved aging stability for integrated optics". In Photonics Europe, a cura di Giancarlo C. Righini e Seppo Honkanen. SPIE, 2004. http://dx.doi.org/10.1117/12.545488.

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de Andrés, Alicia, Carlos Redondo-Obispo, Esteban Climent-Pascual, Javier Bartolomé-Vilchez, Carlos Zaldo e Carmen Coya. "Light Induced Ion Migration in Bi-Doped MAPbI3 for Enhanced Photo-Stability". In 2nd nanoGe International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics. València: Fundació Scito, 2019. http://dx.doi.org/10.29363/nanoge.nipho.2020.051.

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Ravichandran, Sharon, S. G. Bharathi Dasan e R. P. Kumudini Devi. "Small signal stability analysis of grid connected Photo Voltaic distributed generator system". In 2011 International Conference on Power and Energy Systems (ICPS). IEEE, 2011. http://dx.doi.org/10.1109/icpes.2011.6156620.

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Sarkas, H. W., S. R. Flom, F. J. Bartoli e Z. H. Kafafi. "Enhanced Photo-oxidative Stability and Nonlinear Optical Response of a Dialkoxy-Substituted Poly-Phenylenevinylene through C60 Addition". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.md.34.

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The conjugated polymer poly-phenylenevinylene (PPV) and its derivatives have been the subject of numerous nonlinear optical1 and light-emitting diode2 studies. These polymers can photobleach in the presence of oxygen and the photo-oxidation can modify their optical properties.3 For instance, it was recently shown that the nonexponential photoluminescence decay of this polymer is caused by exciton quenching at defects.4 One type of defect has been identified as carbonyl groups formed on the polymer chain as a result of photo-oxidation.3 The present work explores the effect of C60 doping on the photo-oxidative stability and the nonlinear optical (NLO) response of a derivative of PPV called poly-[2-methoxy,5-(2’-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV). Photoinduced electron transfer from the excited state of MEH-PPV to C60 has been reported to occur on a subpicosecond time scale.3 By direct excitation into the tail of the π-π* transition of MEH-PPV, one may be able to access this charge transfer state, stabilize MEH-PPV against photo-oxidation, and enhance the NLO properties of the composite material.

Hossain, Istiaque, Liang Zhang, Ranjith Kottokkaran, Mohamed El-Henawey, Pranav Joshi, Max Noack e Vikram Dalal. "Influence of Grain Size and Interfaces on Photo-Stability of Perovskite Solar Cells". In 2017 IEEE 44th Photovoltaic Specialists Conference (PVSC). IEEE, 2017. http://dx.doi.org/10.1109/pvsc.2017.8366303.

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Kaneki, Takayuki, Yu Shoji, Chika Hibino e Hitoshi Araki. "Negative-Tone Photo-Definable Polyimide with High Thermal Stability and Thick Film Processability". In 2023 24th European Microelectronics and Packaging Conference & Exhibition (EMPC). IEEE, 2023. http://dx.doi.org/10.23919/empc55870.2023.10418340.

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Rapporti di organizzazioni sul tema "(Photo)stability":

Christopher, David A., e Avihai Danon. Plant Adaptation to Light Stress: Genetic Regulatory Mechanisms. United States Department of Agriculture, maggio 2004. http://dx.doi.org/10.32747/2004.7586534.bard.

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Abstract (sommario):

Original Objectives: 1. Purify and biochemically characterize RB60 orthologs in higher plant chloroplasts; 2. Clone the gene(s) encoding plant RB60 orthologs and determine their structure and expression; 3. Manipulate the expression of RB60; 4. Assay the effects of altered RB60 expression on thylakoid biogenesis and photosynthetic function in plants exposed to different light conditions. In addition, we also examined the gene structure and expression of RB60 orthologs in the non-vascular plant, Physcomitrella patens and cloned the poly(A)-binding protein orthologue (43 kDa RB47-like protein). This protein is believed to a partner that interacts with RB60 to bind to the psbA5' UTR. Thus, to obtain a comprehensive view of RB60 function requires analysis of its biochemical partners such as RB43. Background & Achievements: High levels of sunlight reduce photosynthesis in plants by damaging the photo system II reaction center (PSII) subunits, such as D1 (encoded by the chloroplast tpsbAgene). When the rate of D1 synthesis is less than the rate of photo damage, photo inhibition occurs and plant growth is decreased. Plants use light-activated translation and enhanced psbAmRNA stability to maintain D1 synthesis and replace the photo damaged 01. Despite the importance to photosynthetic capacity, these mechanisms are poorly understood in plants. One intriguing model derived from the algal chloroplast system, Chlamydomonas, implicates the role of three proteins (RB60, RB47, RB38) that bind to the psbAmRNA 5' untranslated leader (5' UTR) in the light to activate translation or enhance mRNA stability. RB60 is the key enzyme, protein D1sulfide isomerase (Pill), that regulates the psbA-RN :Binding proteins (RB's) by way of light-mediated redox potentials generated by the photosystems. However, proteins with these functions have not been described from higher plants. We provided compelling evidence for the existence of RB60, RB47 and RB38 orthologs in the vascular plant, Arabidopsis. Using gel mobility shift, Rnase protection and UV-crosslinking assays, we have shown that a dithiol redox mechanism which resembles a Pill (RB60) activity regulates the interaction of 43- and 30-kDa proteins with a thermolabile stem-loop in the 5' UTR of the psbAmRNA from Arabidopsis. We discovered, in Arabidopsis, the PD1 gene family consists of II members that differ in polypeptide length from 361 to 566 amino acids, presence of signal peptides, KDEL motifs, and the number and positions of thioredoxin domains. PD1's catalyze the reversible formation an disomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. PD1's have also evolved novel cellular redox functions, as single enzymes and as subunits of protein complexes in organelles. We provide evidence that at least one Pill is localized to the chloroplast. We have used PDI-specific polyclonal and monoclonal antisera to characterize the PD1 (55 kDa) in the chloroplast that is unevenly distributed between the stroma and pellet (containing membranes, DNA, polysomes, starch), being three-fold more abundant in the pellet phase. PD1-55 levels increase with light intensity and it assembles into a high molecular weight complex of ~230 kDa as determined on native blue gels. In vitro translation of all 11 different Pill's followed by microsomal membrane processing reactions were used to differentiate among PD1's localized in the endoplasmic reticulum or other organelles. These results will provide.1e insights into redox regulatory mechanisms involved in adaptation of the photosynthetic apparatus to light stress. Elucidating the genetic mechanisms and factors regulating chloroplast photosynthetic genes is important for developing strategies to improve photosynthetic efficiency, crop productivity and adaptation to high light environments.