Добірка наукової літератури з теми "Organic synthesis, dyes, photovoltaics, DSSC"

Purpose Dye-sensitised solar cells (DSSCs) have attracted a great deal of interest. Dye molecules are key materials in DSSCs that produce electrons. This study reports on synthesis of the organic dyes and investigation their performance in DSSCs. Design/methodology/approach A series of new organic dyes were prepared using double rhodanine as the fundamental electron-acceptor group and aldehydes with varying substituents as the electron-donor groups. These dyes were first purified and then characterised by analytical techniques. DSSCs were fabricated to determine the photovoltaic behaviour and conversion efficiency of each individual dye. Findings Results demonstrated that all the dyes form j-type aggregates on the nano TiO2. All dyes in DSSC structure show suitable power conversion efficiency, and Dye 5 due to presence of OCH3 and OiPr presents maximum conversion efficiency. Practical implications In the search for high-efficiency organic dyes for DSSCs, development of new materials offering optimised photochemical stabilities as well as suitable optical and electrical properties is importance. Social implications Organic dyes as photosensitisers are interesting due to low cost, relatively facile dye synthesis and capability of easy molecular tailoring. Originality/value A series of new organic metal-free dyes were prepared as sensitisers for DSSCs for the first time.

The investigation of new photosensitizers for Grätzel-type organic dye-sensitized solar cells (DSSCs) remains a topic of interest for researchers of alternative solar cell materials. Over the past 20 years, considerable and increasing research efforts have been devoted to the design and synthesis of new materials, based on “donor, π-conjugated bridge, acceptor” (D–π–A) organic dye photosensitizers. In this paper, the computational chemistry methods are outlined and the design of organic sensitizers (compounds, dyes) is discussed. With reference to recent literature reports, rational molecular design is demonstrated as an effective process to study structure–property relationships. Examples from established organic dye sensitizer structures, such as TA-St-CA, Carbz-PAHTDDT (S9), and metalloporphyrin (PZn-EDOT), are used as reference structures for an examination of this concept applied to generate systematically modified structural derivatives and hence new photosensitizers (i.e., dyes). Using computer-aided rational design (CARD), the in silico design of new chromophores targeted an improvement in spectral properties via the tuning of electronic structures by substitution of molecular fragments, as evaluated by the calculation of absorption profiles. This mini review provides important rational design strategies for engineering new organic light-absorbing compounds towards improved spectral absorption and related optoelectronic properties of chromophores for photovoltaic applications, including the dye-sensitized solar cell (DSSC).

We report Ag nanoparticles infused with mesosphere TiO2/reduced graphene oxide (rGO) nanosheet (TiO2/rGO/Ag) hybrid nanostructures have been successfully fabricated using a series of solution process synthesis routes and an in-situ growth method. The prepared hybrid nanostructure is utilized for the fabrication of photovoltaic cells and the photocatalytic degradation of pollutants. The photovoltaic characteristics of a dye-sensitized solar cell (DSSC) device with plasmonic hybrid nanostructure (TiO2/rGO/Ag) photoanode achieved a highest short-circuit current density (JSC) of 16.05 mA/cm2, an open circuit voltage (VOC) of 0.74 V and a fill factor (FF) of 62.5%. The fabricated plasmonic DSSC device exhibited a maximum power conversion efficiency (PCE) of 7.27%, which is almost 1.7 times higher than the TiO2-based DSSC (4.10%). For the photocatalytic degradation of pollutants, the prepared TiO2/rGO/Ag photocatalyst exhibited superior photodegradation of methylene blue (MB) dye molecules at around 93% and the mineralization of total organic compounds (TOC) by 80% in aqueous solution after 160 min under continuous irradiation with natural sunlight. Moreover, the enhanced performance of the DSSC device and the MB dye degradation exhibited by the hybrid nanostructures are more associated with their high surface area. Therefore, the proposed plasmonic hybrid nanostructure system is a further development for photovoltaics and environmental remediation applications.

The molecular configuration, synthesis and characterization of (E)-3-(6-bromo-9-phenyl-9H-carbazol- 3-yl)acrylic acid (BPA), (E)-3-(6-bromo-9-phenyl-9H-carbazol-3-yl)-2-cyanoacrylic acid (BPCA) and (E)-N′-((6-bromo-9-phenyl-9H-carbazol-3-yl)methylene)-2-cyanoacetohydrazide (BPCH) configured D-π-A sensitizers and the sensitizers are used in DSSCs. Dye molecules are described by FT-IR, NMR and UV-Vis analysis. The study shows that the non-planar structure of BPA, BPCA and BPCH can effectively slow down the aggregation and conjugation of the dye. Computed vibrational modes are compared with observed bands. The Frontier molecular orbital (FMO) and molecular electrostatic potential (MEP) have also been calculated using DFT-B3LYP/6-311++G(d,p) basis set. Physical-chemical parameters have also been analyzed using density functional theory. The most excellent DSSC performance in photovoltaic characterization is demonstrated by the dye molecules.

Dye sensitized solar cells (DSSCs) provide promisingly, organic–inorganic, clean hybrid, cost effective and efficient molecular solar cell devices. Due to their distinct and multifunctional qualities, zinc oxide (ZnO) nanostructures are promising materials used to create photoanodes for DSSCs due to the availability of larger surface area than bulk sheet substance, effectual light-dispersing centers, and when mixed with titanium dioxide they produce a core–shell formation that diminishes the coalition rate and provide direct charge. Moreover, ZnO thin sheets have been broadly observed due of its potential application in various fields i.e. piezoelectric, photovoltaic, pyroelectric and optoelectronic utilization. This review studies the recent advances in the fabrication of zinc oxide-based photovoltaics; synthesis of ZnO nanostructures with variable morphologies including thin sheets, nanotubes, nanorods, nanoflowers, nanofibers and factors that control the growth and morphologies of these nanospecies and part of crystallographic planes for the fabrication of various zinc oxide nanoshapes. In the next part of this paper, numerous fabrication routes — doped and undoped ZnO thin films — are discussed and different parameters of photovoltaics are investigated, e.g. efficiency pre and post annealing temperatures, fill factors spinning speed and coating time, additives, nature of precursor which impacts on morphological and optical parameters of these sheets. In short, this review is dedicated to the ZnO photoanode, its properties, issues related to ZnO photoanode, various improvement approaches, fabrication methods successfully trialled so far followed by market potential of the DSSC technology, conclusion and recommendations

A set of 3-ethynylaryl coumarin dyes with mono, bithiophenes and the fused variant, thieno [3,2-b] thiophene, as well as an alkylated benzotriazole unit were prepared and tested for dye-sensitized solar cells (DSSCs). For comparison purposes, the variation of the substitution pattern at the coumarin unit was analyzed with the natural product 6,7-dihydroxycoumarin (Esculetin) as well as 5,7-dihydroxycomarin in the case of the bithiophene dye. Crucial steps for extension of the conjugated system involved Sonogashira reaction yielding highly fluorescent molecules. Spectroscopic characterization showed that the extension of conjugation via the alkynyl bridge resulted in a strong red-shift of absorption and emission spectra (in solution) of approximately 73–79 nm and 52–89 nm, respectively, relative to 6,7-dimethoxy-4-methylcoumarin (λabs = 341 nm and λem = 410 nm). Theoretical density functional theory (DFT) calculations show that the Lowest Unoccupied Molecular Orbital (LUMO) is mostly centered in the cyanoacrylic anchor unit, corroborating the high intramolecular charge transfer (ICT) character of the electronic transition. Photovoltaic performance evaluation reveals that the thieno [3,2-b] thiophene unit present in dye 8 leads to the best sensitizer of the set, with a conversion efficiency (η = 2.00%), best VOC (367 mV) and second best Jsc (9.28 mA·cm−2), surpassed only by dye 9b (Jsc = 10.19 mA·cm−2). This high photocurrent value can be attributed to increased donor ability of the 5,7-dimethoxy unit when compared to the 6,7 equivalent (9b).

ABSTRACTOver the last 30 years organic carbon nanotube-yarn (CNTY) based dye-sensitized solar cells (DSSCs) have received considerable interest. CNTY based DSSCs have become a main focus of alternative energy source research. CNTY based PV cells have an advantage over cells based on non-flexible substrates, such as fluorine doped tin oxide glass; as a foundation for dye-sensitized solar cells, CNTYs are superior due to their low-cost, environmental sustainability, high mechanical integrity, and numerous beneficial practical applications. CNTY based DSSCs also have additional advantages because of their low electrical resistance, excellent electrocatalytic activity, and ultra-high mechanical integrity. Additionally, quantum dots and polymers have shown great promise for photovoltalic application due to their tunable bandgap and wide photon absorption range. This research explores the barrier characteristics associated with new absorbing photovoltaic materials that promote electron/hole pair separation and transportation. Utilizing the hybrid bandgap structures of quantum dots and polymers as well as the flexibility of CNTY, we reported a 3D flexible DSSC with an efficiency of 2.9%.

Three novel pyrazine-based organic photosensitizers denoted as TPP, TPPS, and TPPF were synthesized for dye-sensitized solar cell (DSSC) studies. Chemical structures of the pyrazine-based photosensitizers were designed with pyrazine derivatives as acceptors, triphenylamine groups as donors, and the thiophene–cyanoacryl group as an auxiliary heterocyclic linkers-acceptor. Using UV-vis spectrophotometry, cyclic voltammetry, and density functional theory calculations, optical and electrochemical characteristics of these pyrazine-based photosensitizers were examined and explored in relation to photovoltaic parameters. The effects of the molecular structures of these photosensitizers on the performances of DSSCs were also investigated. The overall conversion efficiencies of DSSCs based on pyrazine-based photosensitizers were 1.31~2.64% under AM 1.5 irradiation of 100 mW/cm2. To confirm the effect of interfacial charge transfer on photovoltaic performances of DSSC based on pyrazine-based photosensitizers, interfacial charge transfer resistances were investigated by electrical impedance spectroscopy (EIS) measurements.

Organic solvents used for electrolytes of dye-sensitized solar cells (DSSCs) are generally not only toxic and explosive but also prone to leakage due to volatility and low surface tension. The representative dyes of DSSCs are ruthenium-complex molecules, which are expensive and require a complicated synthesis process. In this paper, the eco-friendly DSSCs were presented based on water-based electrolytes and a commercially available organic dye. The effect of aging time after the device fabrication and the electrolyte composition on the photovoltaic performance of the eco-friendly DSSCs were investigated. Plasma treatment of TiO2 was adopted to improve the dye adsorption as well as the wettability of the water-based electrolytes on TiO2. It turned out that the plasma treatment was an effective way of improving the photovoltaic performance of the eco-friendly DSSCs by increasing the efficiency by 3.4 times. For more eco-friendly DSSCs, the organic-synthetic dye was replaced by chlorophyll extracted from spinach. With the plasma treatment, the efficiency of the eco-friendly DSSCs based on water-electrolytes and chlorophyll was comparable to those of the previously reported chlorophyll-based DSSCs with non-aqueous electrolytes.

El creixement de la població i dels nous països emergents fa que el consum energètic es dispari. Tota la població depèn d’aquest consum i com a conseqüència es depèn de les reserves de combustibles fòssils disponibles. Una de les fonts d’energia no esgotable i que proveu a la terra d’una gran quantitat d’energia es el Sol. Aquesta Energia ja està sent explotada amb la utilització de panells solars basades en silici. No obstant degut al seu alt cost de fabricació no poden competir amb les fonts d’energia ja existents. Per tant, noves investigacions en alternatives han estat àmpliament estudiades. Unes de les alternatives que han estat àmpliament estudiades durant aquests anys han estat les cel·les sensitivitzades amb colorant (DSSC) i les cel·les orgàniques (OPV). Les bases i el funcionament d’aquests dos tipus de dispositius es mostren en el capítol 1. El principal estudi d’aquesta tesis es centra en el disseny i la síntesis de nous colorants per aquest tipus de dispositius. Aquests colorants tenen un paper molt important en aquests dispositius i moltes vegades la seva eficiència deriva de l’estructura d’aquests colorants degut a les reaccions que es produeixen en els dispositius. En el Capítol 3 i 4 es presenta el disseny de dos tipus de colorants pel que fa a les cel·les sensitivitzades amb colorant (DSSC). En el capítol 3 es tracta de noves molècules orgàniques amb estructura D-π-A àmpliament estudiades com a alternativa als complexes de ruteni. En el capítol 4 les molècules sintetitzades també per DSSC són una família de porfirines, les quals són les que actualment estan mostrant més eficiència. Per una altra banda en el capítol 5 s’ha sintetitzat també una porfirina però en aquest cas per estudiar la seva aplicabilitat en les cel·les solars orgàniques (OPV).
El Crecimiento de la población I de nuevos países emergentes hace que el consume energético se dispare. Toda la población depende de este consume I como consecuencia se depende de las reservas de combustibles fósiles disponibles. Una de las Fuentes de energía no agotable y que suministra a la tierra de una gran cantidad de energía es el Sol. Esta energía ya está siendo explotada con la utilización de paneles solares basados en Silicio. Sin embargo, debido a su elevado coste de fabricación no pueden competir con fuentes de energía ya existentes. Por lo tanto, nuevas investigaciones en alternativas han estado estudiadas. Una de las alternativas que han sido más estudiadas son las Celdas sensitibizadas con colorante (DSSC) i las Celdas Orgánicas (OPV). Las bases y su funcionamiento se muestran en el capítulo 1. El principal estudio de esta tesis se centra en el diseño y la síntesis de nuevos colorantes para estos tipos de dispositivos. Estos colorantes tienen un papel muy importante en estos dispositivos y muchas veces su eficiencia deriva de la estructura del colorante debido a reacciones que se producen en el dispositivo. En el Capítulo 3 y 4 se presenta el diseño de dos tipos de colorantes para las celdas sensitibizadas con colorante. En el Capítulo 3 se muestran moléculas orgánicas con estructura D--A que han sido ampliamente estudiadas como alternativa a los complejos de rutenio. En el capítulo 4 una familia de porfirinas ha sido sintetizada debido a los prometedores resultados mostrados siendo en la actualidad las moléculas que dan más eficiencia. En el Capítulo 5 en cambio se ha sintetizado una porfirina, pero en este caso para estudiar su aplicabilidad en las celdas orgánicas (OPV)
The population is growing and the consumption of energy is dramatically increasing. All the population depends on this energy and are using fossil fuels available. One of this renewable source that gives to the earth a huge amount of energy is the sun. This source is exploited nowadays with photovoltaic devices based in silicon. However due to their high cost of production is not an alternative comparing with the existent sources. For this reason scientists of the entire world are working hard in the development of alternative devices in order to reduce the cost, decrease the contamination and increase the efficiencies among others. Some of alternatives that have been widely studied during the last years have been the Dye Sensitized Solar Cells (DSSC) and Organic Solar Cells (OPV). Basic principles of these devices are showed in Chapter 1. Principally the study of this thesis was focused in the design and synthesis of new sensitizers for these devices. These sensitizers play an important role in these devices and many times their structure depends on the efficiency of the device. In Chapter 3 and 4 the design and synthesis of two kinds of sensitizers and their applicability in DSSC is showed. In chapter 3 the sensitizers are organic dyes with a structure of D-π-A widely studied as alternative to the ruthenium complexes. In chapter 4 another family of sensitizers have been synthesized and also their applicability in DSSC has been studied. In this chapter the molecules are a family of porphyrins that are the molecules that nowadays are showing the most efficiency. On the other hand in Chapter 5 a new porphyrin has been synthesized but in this case to study their applicability in Organic solar Cells (OPV)

Dye-sensitized solar cells (DSSCs) present an interesting method for the conversion of sunlight into electricity. Unlike in other photovoltaic technologies, the difficult tasks of light absorption and charge transport are handled by two different materials in DSSCs. At the heart of the DSSC, molecular light absorbers (dyes) are responsible for converting light into current. In this thesis the design, synthesis and properties of new metal-free D-π-A dyes for dye-sensitized solar cells will be explored. The thesis is divided into six parts: Part one offers a general introduction to DSSCs, dye design and device characterization. Part two is an investigation of a series of donor substituted dyes where structural benefits are compared against electronic benefits. In part three a dye assembly consisting of a chromophore tethered to two electronically decoupled donors is described. The assembly, capable of intramolecular regeneration, is found to impede recombination. Part four explores a method for rapidly synthesizing new D-π-A dyes by dividing them into donor, linker and acceptor fragments that can be assembled in two simple steps. The method is applied to synthesize a series of linker varied dyes for cobalt based redox mediators that builds upon the experience from part two. Part five describes the synthesis of a bromoacrylic acid based dye and explores the photoisomerization of a few bromo- and cyanoacrylic acid based dyes. Finally, in part six the experiences from previous chapters are combined in the design and synthesis of a D-π-A dye bearing a new pyridinedicarboxylic acid acceptor and anchoring group.

QC 20140509

Presently, Dye-Sensitized Solar Cells (DSSCs) are considered one of the most promising technologies to convert solar energy in electric current due to their low cost of production, their innovative aesthetic properties and their easy integration in buildings and objects. The dye, which can be a completely organic molecule, is the photoactive material and is considered the heart of the DSSC. Exceeding the current record efficiency is not the unique goal which can be pursued in order to make DSSC the most relevant photovoltaic technology: stability, transparency and color are pivotal properties for a future worldwide commercialization of DSSCs. During this Ph.D., these targets have been pursued by working on the structure of new organic photosensitizers. A careful design of the structures through computational analysis has been accomplished, then the synthesis of the selected dyes has been planned and executed, and the optimization of reaction conditions using sustainable procedure has been carried out when possible. Finally, the photovoltaic performances of the solar cells built with our dyes have been assessed and compared with those of reference dyes.

碩士
中華大學
機械工程學系碩士班
101
The dye-sensitized solar cells (DSSC) in this research are coated with FTO transparent conductive film on the glass substrate. The photo voltaic performance of several DSSCs with different natural dyes and synthetic dye (such as N719) are studied. The first step of making DSSC is to deposit a layer of TiO2 as the electrode. Then soak the electrode into a liquid containing natural dye and N719 for several hours. After drying the electrode with air gun and use platinum as the counter electrode, the final one is to fill the electrolytic solution into the cell and then sealing for performance testing. Besides, this research took several extraction methods of natural dye into consideration. Firstly, grinding and dip the dyes into acetone, the next is ultrasonic oscillation or heating to extract the dye. Finally, plotting the IV curves and comparing the maximum conversion performances by using natural and synthetic dyes. One can see that the conversion efficiency by using synthetic dyes is better than those obtained by natural dyes. Moreover, the combinations by connecting the solar cells in series or in parallel are also studied; note that the parallel connection method can give a larger power conversion with a solar simulator at the same power irradiation.

This chapter has been mainly focused on the development and fabrication of various nanostructured materials for electrochemical energy conversion, specially, third generation (3rd) thin film photovoltaic system such as organic dye or perovskite -sensitized Solar Cells. Enormous efforts have been dedicated to the development of a variety of clean energy, capable of harvesting energy of various forms. Among the various energy forms, electrochemical devices that produce electric energy from chemical energy have received the most attention as the most promising power sources. In the majority of cases, researchers who come from the different background could engage on certain aspects of the components to improve the photovoltaic performances from different disciplines: (i) chemists to design and synthesize suitable donor–acceptor dyes and study structure–property relationships; (ii) physicists to build solar cell devices with the novel materials, to characterize and optimize their performances, and to understand the fundamental photophysical processes; and (iii) engineers to develop new device architectures. The synergy between all the disciplines will play a major role for future advancements in this area. However, the simultaneous development of all components such as photosensitizers, hole transport layer, photoanodes and cost effective cathode, combined with further investigation of transport dynamics, will lead to Photovoltaic cells, 30%. Herein, in this book, with taking optimized processing recipe as the standard cell fabrication procedure, imporant breakthough for each components is achieved by developing or designing new materials, concepts, and fabrication technique. This book report the following studies: (i) a brief introduction of the working principle, (ii) the detailed study of the each component materials, mainly including TiO2 photoanode under the category of 0D and 3D structures, strategies for co-sensitization with porphyrin and organic photosensitizers, and carbon catalytic material via controlled fabrication protocols and fundamental understanding of the working principles of electrochemical photovoltaic cell has been gained by means of electrical and optical modelling and advanced characterization techniques and (iii) new desgined stratages such as the optimization of photon confinement (iv) future prospects and survival stratagies for sensitizer assisted solar cell (especially, DSSC).

Green synthesis of nanoparticles has grown substantial interest as a developing technology to reduce the toxicity of metal oxide commonly associated with conventional physical and chemical synthesis methods. Among these, green synthesis of nanoparticles from plants parts to be a very active method in developing nontoxic, eco-friendly and clean technology. We prepared green synthesized TiO2 using a fruits extract of Averrhoa bilimbi with a cost effective and non-toxic method and reports better PCE of DSSCs application. The green synthesized TiO2 nanoparticles (working electrode) with DPT dopant PEG polymer electrolyte shows better power conversion efficiency in dye-sensitized solar cells. The green TiO2 was characterized with XRD, UV, FTIR, SEM, TEM and EDX techniques analysis the band gap, crystallite size and shape for green synthesized TiO2 nanoparticles. The electrical and mechanical properties of DPT organic doped PEG/KI/I2 polymer electrolyte were characterized with XRD, FTIR, EIS, DSC and TGA and it was analysis that the DPT well miscible with PEG polymer electrolyte and improves the electrical conductivity and enhances the efficiency of DSSC.