Power Conversion Efficiency Of Dye-sensitized Solar Cells Research Articles

A general approach for synthesis of functional metal oxide nanotubes and their application in dye-sensitized solar cells

TiO2, SnO2, ZnO, Fe2O3, and ZrO2 nanotubes were synthesized through a combination of templating and solvothermal processes. Selenium nanowires have been used as a template for the first time to synthesis a family of functional metal oxide nanotubes. The nanotubes so obtained were composed of fine particles with sizes as small as 6–8 nm. These nanotubes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectra. The influence of TiO2 nanotubes on the performance of dye-sensitized solar cells (DSSCs) based on the TiO2 nanotube/nanoparticle composite films was investigated. The power conversion efficiency of DSSC was enhanced from 5.84% for the pure nanoparticle film to 6.66% for the composite film with 10 wt% nanotubes. Advantages of this method include that it is a simple and general process that can open new avenues for the synthesis of a variety of functional nanotube structures.

Fabrication and Evaluation of Titanium Dioxide Nanotube Thin Films by Anodic Oxidation on Transparent Electrodes

Titanium dioxide nanotube (TNT) thin films were fabricated, for application as the negative electrode of dye-sensitized solar cells (DSC), by anodic oxidation of titanium thin films deposited by RF magnetron sputtering on indium tin oxide glass substrates. Anodic oxidation was carried out by a constant voltage or constant current method in an electrolyte in order to determine the best method to increase TNT film thickness. Thick titanium dioxide films were fabricated by the constant voltage method at higher voltages. Thicker titanium dioxide films were obtained by the constant current method compared to the constant voltage method. However, the constant current method with optimal current yielded TNT films with higher quality (high transparency). The power conversion efficiency of DSC was improved using films fabricated by the constant current method.

Synthesis and photovoltaic properties of main chain polymeric metal complexes containing 8-hydroxyquinoline metal complexes conjugating alkyl fluorene or alkoxy benzene by CN bridge for dye-sensitized solar cells

Four main chain polymeric metal complexes (P1–P4) based on 8-hydroxyquinoline metal complexes have been synthesized by the Heck coupling and characterized by gel-permeation chromatography, Fourier transform infrared spectroscopy, proton-nuclear magnetic resonance, thermogravimetric analysis, ultraviolet–visible absorption, photoluminescence spectroscopy, elemental analysis, and cyclic voltammetry. The applications of these polymers as dye sensitizers in dye-sensitized solar cells (DSSCs) are also studied. The study results show that the solar cells have good device performance with power conversion efficiency of P1–P4 up to 2.17, 2.04, 2.45, and 2.18%, respectively. The highest power conversion efficiency of DSSCs is up to 2.45%, for P3 consisting of alkoxy benzene unit and Cd–metal complex under the illumination of air mass 1.5 G, 100 mW cm−2. POLYM. COMPOS., 34:1629–1639, 2013. © 2013 Society of Plastics Engineers

TiO2-Nanotube-Based Dye-Sensitized Solar Cells Containing Fluorescent Material

We fabricated a dye-sensitized solar cells (DSCs) with TiO2 nanotube arrays obtained by anodization of Ti foil. Vertical structure of TiO2 nanotube arrays is very attractive due to a high electron transfer from dye to electrode. To improve the power conversion efficiency, fluorescent material, F-6377, was applied in TiO2-nanotube-based DSCs to use a light spectrum efficiently. Fluorescent material was absorbed the different wavelength of 460 nm from the light absorbed by N719 dye. Fluorescent material to emit the absorbed light energy provided an additional light for dye in DSCs and additional electrons was generated. Thickness of TiO2 nanotube arrays grown by anodic oxidation was 15 microm. N719 dye and 13(-)/l(-) electrolyte were used to fabricate the DSCs. The short circuit current densities (J(sc)) and the power conversion efficiency in DSCs with fluorescent were 10.8 mA/cm2 and 2.48%, respectively. Electrochemical impedance spectroscopy (EIS) was observed to understand an electron transfer and life time.

Optimized synthesis and photovoltaic performance of TiO2 nanoparticles for dye-sensitized solar cell

This paper presents response surface methodology (RSM) as an efficient approach for modeling and optimizing TiO2 nanoparticles preparation via co-precipitation for dye-sensitized solar cell (DSSC) performance. Titanium (IV) bis-(acetylacetonate) di-isopropoxide (DIPBAT), isopropanol and water were used as precursor, solvent and co-solvent, respectively. Molar ratio of water, aging temperature and calcination temperature as preparation factors with main and interaction effects on particle characteristics and performances were investigated. Particle characteristics in terms of primary and secondary sizes, crystal orientation and morphology were determined by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Band gap energy and power conversion efficiency of DSSCs were used for performance studies. According to analysis of variance (ANOVA) in response surface methodology (RSM), all three independent parameters were statistically significant and the final model was accurate. The model predicted maximum power conversion efficiency (0.14%) under the optimal condition of molar ratio of DIPBAT-to-isopropanol-to-water of 1:10:500, aging temperature of 36°C and calcination temperature of 400°C. A second set of data was adopted to validate the model at optimal conditions and was found to be 0.14±0.015%, which was very close to the predicted value. This study proves the reliability of the model in identifying the optimal condition for maximum performance.

Highly soluble energy relay dyes for dye-sensitized solar cells

High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, characterized, and resulted in a 65% increase in the efficiency of TT1-sensitized DSSCs. The high solubility (180 mM) of these ERDs allows for absorption of over 95% of incident light at their peak wavelength. The overall power conversion efficiency of DSSCs with BL302 and BL315 was found to be limited by their energy transfer efficiency of approximately 70%. Losses due to large pore size, dynamic collisional quenching of the ERD, energy transfer to desorbed sensitizing dyes and static quenching by complex formation were investigated and it was found that a majority of the losses are caused by the formation of statically quenched ERDs in solution.

Hierarchical vertically oriented graphene as a catalytic counter electrode in dye-sensitized solar cells

Vertically oriented graphene (VG) nanosheets are synthesized for counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). The VG electrode exhibits charge transfer resistance about 1% of the Pt electrode and improves power conversion efficiency of DSSCs from 4.68% (for Pt CEs) to 5.36%.

In situ growth of oriented polyaniline nanowires array for efficient cathode of Co(iii)/Co(ii) mediated dye-sensitized solar cell

To improve the electrocatalytic performance of polyaniline thin films, an oriented polyaniline nanowires array has been successfully grown in situ on conductive glass substrates without templates and applied as the cathode of dye-sensitized solar cells (DSSCs) mediated with a Co(bpy)33+/2+ (bpy = 2,2′-bipyridine) redox couple. Compared to the polyaniline film with a random network, the oriented polyaniline nanowires array exhibits much better electrocatalytic performance, and even outperforms the typical Pt electrode in both electrocatalytic performance and electrochemical stability when exposed to the acetonitrile solution of the Co(bpy)33+/2+ redox couple. Owing to the higher electrocatalytic performance, the DSSC with the oriented nanowires array produces a higher short-circuit photocurrent and fill factor than the DSSCs with the random polyaniline network or Pt cathodes. Consequently, the power conversion efficiency of DSSCs based on a typical D–π–A organic dye sensitizer increases from 5.97% for the polyaniline random network cathode to 8.24% for the oriented polyaniline nanowires array cathode, which is also higher than the efficiency (6.78%) of the DSSC with the Pt cathode.

Synthesis and photo-electrochemical properties of novel thienopyrazine and quinoxaline derivatives, and their dye-sensitized solar cell performance

Light absorption from visible to NIR region is required to increase the photocurrent and to enhance the photo-energy conversion efficiencies in dye-sensitized solar cells (DSSCs). We have now developed novel thienopyrazine dye TP1 which has absorption up to 700nm. Quinoxaline dye QX2 with absorption at shorter wavelengths than TP1 has been synthesized for comparisons. The power conversion efficiencies of DSSCs with TP1 and QX2 showed 4.4% and 3.2%, respectively. The absorption edge in IPCE of TP1 reached 800nm and the open circuit voltage (Voc) of QX2 was high (0.77V). To improve the device performances, QX2 was used as a co-adsorbent dye with TP1. In the mixed sensitizer based DSSC, a high power conversion efficiency of 6.2% was achieved due to the effective light harvesting and steric effect of QX2.

Preparation of a working electrode with a conducting PEDOT:PSS film and its applications in a dye-sensitized solar cell

This study investigates the applicability of a working electrode with a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) film on a dye-sensitized solar cell (DSSC). This working electrode was designed and fabricated by inserting a PEDOT:PSS film between a fluorine-doped tin oxide (FTO) glass substrate and a layer of nanocrystalline TiO2 particles (P-25). This study also examines the effects of annealing temperature and duration on the transmittance and microstructure of a PEDOT:PSS film as well as the power conversion efficiency of DSSC with this film. The power conversion efficiency of a DSSC with a PEDOT:PSS film (6.37%) substantially exceeds that of a conventional DSSC (4.24%). This result is attributed to the fact that this transparent and conductive PEDOT:PSS film deposited on the FTO glass substrate using a simple spin coating method substantially improves the short-circuit photocurrent per unit area and the fill factor of DSSC.

Sputter-deposited ZnO thin films consisting of nano-networks for binder-free dye-sensitized solar cells

ZnO nano-network structures with high porosity were prepared for use in the photoelectrodes of binder-free dye-sensitized solar cells (DSSCs) by DC sputtering and subsequent thermal oxidation. Zn thin films prepared at 100 °C showed nano-network structures with high porosity, while those prepared at 25 °C did not. This was partially attributed to the high mobility of sputter-deposited particles that arrived at the surface of the substrate and partially to a supersaturation mechanism. The prepared nano-network Zn was successfully transformed to ZnO without a morphological change via subsequent annealing in air. The power conversion efficiency of DSSCs based on the ZnO nano-network structures exhibited 10 times higher efficiency than those based on ZnO film prepared at 25 °C because of its large surface area for adsorption of dye molecules. The thickness of the ZnO nano-network structures increased linearly at 10 μm h−1 as a function of sputter time. As the film thickness increased, the power conversion efficiency of DSSCs increased from 1.09% to 1.82%.

Promoting Effect of Graphene on Dye-Sensitized Solar Cells

In this paper, a simple approach without a prereduction of graphene oxide was exploited to prepare a graphene-doped TiO2 film for dye-sensitized solar cells (DSSCs). The performance measurement of the DSSCs showed that the incorporation of graphene could increase the short-circuit current density and power conversion efficiency by 52.4 and 55.3%, respectively. Furthermore, it was demonstrated that the performance enhancement was due to the promoting effect of graphene on electron transfer instead of the increase of dye loading in TiO2/graphene composite films. However, graphene can also absorb solar light, which could lead to the decrease of light harvest of dye molecules and thus a negative effect on the power conversion efficiency of DSSCs. Furthermore, graphene might decrease the actual dye loading on TiO2 in a TiO2/graphene film, which can also make a negative contribution to the conversion efficiency. As a result, the promoting effect of graphene is strongly dependent on its content; namely, the efficiency of DSSCs increases to the maximum value and then decreases with increasing graphene content in TiO2/graphene composites.

Organic and inorganic surface passivations of TiO2 nanotube arrays for dye-sensitized photoelectrodes

Surface passivation of photoelectrodes is widely used to improve the performance of dye-sensitized solar cells (DSCs). We use the organic and inorganic materials as a surface-passivating layer of photoelectrodes and introduce the effect of surface passivation on the power conversion efficiency of DSCs. TiO2 nanotube arrays are fabricated by anodic oxidation of Ti foil for photoelectrodes of DSCs. Surface passivating layers are conducted by immersing photoelectrode in various precursor solutions. MgO and WO3 are selected for inorganic passivation. PC61BM is used for organic passivation. In case of inorganic passivation, a basic material (MgO) which has a high isoelectric point (pI >7) shows higher power conversion efficiency of 2.63% by increasing of open circuit voltage (Voc) to 0.74 V than bare sample of 2.55%. But, an acidic material (WO3) shifts Voc to low potential resulting in a worse efficiency of DSCs. In case of organic passivation, PC61BM enhances photocurrents and decreases Voc value compared to bare sample. The power conversion efficiency of PC61BM-coated DSCs is overall improved due to enhanced photocurrents despite of Voc offset to low potential. Back-transfer electron blocking, dye adsorption, TiO2 conduction band shifting, and additional charge generation by surface passivation are discussed.

The Method to Determine the Optimal La<sup>3+</sup> Doping in DSSC Electrode for BIPV

Dye-Sensitized Solar Cell (DSSC) is noticed to be proper for BIPV for cheaper, more transparent, and able to realizevarious colored. Researchers constantly strive to improve the power conversion efficiency of DSSCs for this cell’s practicability by doping TiO2Subscript text with inorganic substance, metal ions, or processed with organic, as TiO2 electrode is the core of DSSC to generate photovoltage effection. Here reported a method to determine the optimal La3+ doping proportion of TiO2 by the equivalent circuit parameters estimated corresponds to the reported experment I-V curve. Thus, the concentration of La3+ doped TiO2 thin films of 0.5% of DSSC can get the most out of the photoelectric conversion efficiency.

Influence of Surface-Attachment Functionality on the Aggregation, Persistence, and Electron-Transfer Reactivity of Chalcogenorhodamine Dyes on TiO2

Chalcogenorhodamine dyes bearing phosphonic acids and carboxylic acids were compared as sensitizers of nanocrystalline TiO(2) in dye-sensitized solar cells (DSSCs). The dyes were constructed around a 3,6-bis(dimethylamino)chalcogenoxanthylium core and varied in the 9 substituent: 5-carboxythien-2-yl in dyes 1-E (E = O, Se), 4-carboxyphenyl in dyes 2-E (E = O, S), 5-phosphonothien-2-yl in dyes 3-E (E = O, Se), and 4-phosphonophenyl in dyes 4-E (E = O, Se). All dyes adsorbed to TiO(2) as mixtures of H aggregates and monomers, which exhibited broadened absorption spectra relative to those of purely amorphous monolayers. Surface coverages of dyes and the extent of H aggregation varied minimally with the surface-attachment functionality, the structure of the 9-aryl group, and the identity of the chalcogen heteroatom. Carboxylic acid-functionalized dyes 1-E and 2-E desorbed rapidly and completely from TiO(2) into acidified CH(3)CN, but phosphonic acid-functionalized dyes 3-E and 4-E persisted on TiO(2) for days. Short-circuit photocurrent action spectra of DSSCs corresponded closely to the absorptance spectra of dye-functionalized films; thus, H aggregation did not decrease the electron-injection yield or charge-collection efficiency. Maximum monochromatic incident photon-to-current efficiencies (IPCEs) of DSSCs ranged from 53 to 95% and were slightly higher for carboxylic acid-functionalized dyes 1-E and 2-E. Power-conversion efficiencies of DSSCs under white-light illumination were low (<1%), suggesting that dye regeneration was inefficient at high light intensities. The photoelectrochemical performance (under monochromatic or white-light illumination) of 1-E and 2-E decayed significantly within 20-80 min of the assembly of DSSCs, primarily because of the desorption of the dyes. In contrast, the performance of phosphonic acid-functionalized dyes remained stable or improved slightly on similar timescales. Thus, replacing carboxylic acids with phosphonic acids increased the inertness of chalcogenorhodamine-TiO(2) interfaces without greatly impacting the aggregation of dyes or the interfacial electron-transfer reactivity.

Enhanced light-harvesting efficiency by Förster resonance energy transfer in quasi-solid state DSSC using organic blue dye

We have demonstrated Förster resonance energy transfer (FRET) between organic fluorescent materials (as an energy donor) doped in fluorinated-polymer gel electrolyte and organic blue dye (as an energy acceptor on TiO2 surfaces in dye-sensitized solar cells (DSSCs)). The judicious choice of the energy donor and electron acceptor allows a strong spectral overlap of the emission/absorption of energy donor and acceptor, which could enhance the light-harvesting characteristics of the energy acceptor in quasi-solid DSSCs. The power conversion efficiency of DSSCs containing fluorescent material in a quasi-solid electrolyte increased by 19% over a pristine cell. The optimized cell architecture fabricated with the quasi-solid state DSSC containing the organic blue dye on a photoanode shows a maximum efficiency of 2.15%, with a short-circuit current density (Jsc) of 4.32mAcm−2 and an open-circuit voltage (Voc) of 0.68V under illumination of simulated solar light (AM 1.5G, 100mWcm−2).

Effect of a Fullerene Derivative on the Performance of TiO2-Nanotube-Based Dye-Sensitized Solar Cells

Highly ordered TiO2 nanotube arrays were prepared by anodic oxidation of Ti foil in an application to dye-sensitized solar cells (DSCs). A fullerene derivative called PC61BM was used as a material for the surface modification of TiO2 nanotube arrays to improve the power conversion efficiency of DSCs Although open circuit voltages (Voc) were slightly decreased by PC61BM interlayer, short circuit current densities (Jsc) were increased and thus the power conversion efficiencies were improved. EIS (Electrochemical Impedance Spectroscopy) results showed superior properties for PC61BM-coated samples.

Effects of electron beam irradiation on the photoelectrochemical properties of TiO2 film for DSSCs

TiO 2 has been widely utilized for various industrial applications such as photochemical cells, photocatalysts, and electrochromic devices. The crystallinity and morphology of TiO 2 films play a significant role in determining the overall efficiency of dye-sensitized solar cells (DSSCs). In this study, the preparation of nanostructured TiO 2 films by electron beam irradiation and their characterization were investigated for the application of DSSCs. TiO 2 films were exposed to 20–100 kGy of electron beam irradiation using 1.14 MeV energy acceleration with a 7.46 mA beam current and 10 kGy/pass dose rates. These samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS) analysis. After irradiation, each TiO 2 film was tested as a DSSC. At low doses of electron beam irradiation (20 kGy), the energy conversion efficiency of the film was approximately 4.0% under illumination of simulated sunlight with AM 1.5 G (100 mW/cm 2 ). We found that electron beam irradiation resulted in surface modification of the TiO 2 films, which could explain the observed increase in the conversion efficiency in irradiated versus non-irradiated films. ► The surface of TiO 2 particles was modified by electron beam irradiation. ► The aggregation between each TiO 2 particle was observed in the SEM images. ► Ti 3+ state was enhanced due to the excess electron injection via electron beam irradiation. ► The power conversion efficiency of DSSCs was enhanced.

Preparation of TiO 2 particles and their applications in the light scattering layer of a dye-sensitized solar cell

This study investigates the applicability of a hybrid TiO 2 electrode (or a working electrode with a light scattering layer) in a dye-sensitized solar cell (DSSC). Microcrystalline TiO 2 particles, synthesized by the simple sol–gel method using TiCl 4 ethanol solution as a precursor, were used to prepare a light scattering layer of the working electrode (or a hybrid TiO 2 electrode), and the properties of these microcrystalline TiO 2 particles were measured. This electrode was then immersed in a solution of N-719 (Ruthenium) dye at a temperature of 70 °C for 6 h. Finally, the DSSC was assembled, and the short-circuit photocurrent, the open-circuit photovoltage, and the power conversion efficiency of DSSC were measured using an I– V measurement system. The effect of the average size of TiO 2 particles synthesized by the sol–gel method on the power conversion efficiency of a DSSC was also examined. Most importantly, this study shows that the power conversion efficiency of the DSSC with a hybrid TiO 2 electrode (7.02%), which consisted of 50% TiO 2 particles (P-25) and 50% TiO 2 particles with an average size of 268.7 nm, substantially exceeds that of the conventional DSSC with a TiO 2 (P-25) electrode (5.16%) due to the effect of the light scattering in the DSSC.

Multifunctional Conjugated Polymers with Main‐Chain Donors and Side‐Chain Acceptors for Dye Sensitized Solar Cells (DSSCs) and Organic Photovoltaic Cells (OPVs)

A novel multifunctional conjugated polymer (RCP-1) composed of an electron-donating backbone (carbazole) and an electron-accepting side chain (cyanoacetic acid) connected through conjugated vinylene and terthiophene has been synthesized and tested as a photosensitizer in two major molecule-based solar cells, namely dye sensitized solar cells (DSSCs) and organic photovoltaic cells (OPVs). Promising initial results on overall power conversion efficiencies of 4.11% and 1.04% are obtained from the basic structure of DSSCs and OPVs based on RCP-1, respectively. The well-defined donor (D)-acceptor (A) structure of RCP-1 has made it possible, for the first time, to reach over 4% of power conversion efficiency in DSSCs with an organic polymer sensitizer and good operation stability.