High-efficient fibrous dye-sensitized solar cell with carbon nanotube (CNT) thin films as counter electrodes has been reported. The CNT films were fabricated by coating CNT paste or spraying CNT suspension solution on Ti wires. A fluorine tin oxide-coated CNT underlayer was used to improve the adherence of the CNT layer on Ti substrate for sprayed samples. The charge transfer catalytic behavior of fibrous CNT/Ti counter electrodes to the iodide/triiodide redox pair was carefully studied by electrochemical impedance and current-voltage measurement. The catalytic activity can be enhanced by increasing the amount of CNT loading on substrate. Both the efficiencies of fibrous dye-sensitized solar cells using paste coated and sprayed CNT films as counter electrodes are comparative to that using Pt wires, indicating the feasibility of CNT/Ti wires as fibrous counter electrode for superseding Pt wires.

A sponge-like three dimensional carbon nanotube (CNT) framework has been applied as the counter electrode for a dye-sensitized solar cell (DSC). The CNT-sponge shows high catalytic activity to the counter electrode reduction reactions of I−/I3− redox couple and a photoelectric conversion efficiency of 6.21% has been achieved. Compared with previous carbon-based counter electrode materials for DSCs, the CNT sponge retains highly flexibility and good mechanical strength. Its soft structure makes it possible to directly transfer it onto a substrate to make DSC devices.

PbS/carbon black (CB) composite counter electrode (CE) has been fabricated by a low cost and low temperature processable method using the wet chemistry synthesized PbS nanoparticles. The nanosized PbS in the composite CE provides a large area of catalytic sites, and the chain-type CB framework acts as an excellent electrical tunnel for fast electron transport from an external circuit to highly catalytic PbS nanoparticles. The optimized PbS/CB composite CE shows a charge transfer resistance (R(CT)) as low as 10.28 Ω cm², which is an order of magnitude lower than the value obtained in the previous study on pure PbS CE. The CdS/CdSe quantum dot-sensitized solar cells with the PbS/CB composite CE achieve a photovoltaic conversion efficiency of 3.91% and no degradation of the efficiency over 1000 h under room conditions.

The study of dye-sensitized solar cells (DSCs) has become an important research field for photovoltaic device development.We present a brief description of their basic structure,principle of operation,and essential component materials,as well as recent research progress.Emphasis is placed upon the design of DSC modules.Recent developments and problems are reviewed.

The structure of fibrous dye-sensitized solar cells, which were constructed by a TiO2 nanotube array on Ti wire as the photoanode twisted by a Pt wire counter electrode, has been first systematically investigated by accurately controlling the thread pitch distance of screwed Pt wire. It has been revealed that the thread pitch will strongly influence the photovoltaic performance and kinetic processes in fibrous solar cells. The effect of the length of the TiO2 nanotube on cell performance has also been discussed. After optimization, a relatively universal optimized thread pitch value of 1 mm for fibrous DSCs has been proved and the light-to-electricity conversion efficiency has been remarkably improved to 5.84%.

Dye sensitized solar cells (DSCs) are promising alternative to conventional Si-based solar cells due to their low cost, easy fabrication and relatively high conversion efficiency. In the DSC, the electrolyte plays an important role in the regeneration of dye molecules and the charge transportation. Although the DSCs based on the liquid electrolyte can present much better photovoltaic performance, the disadvantages of the liquid electrolytes (i. e. volatility and easy leakage) are supposed to reduce the long-term stability. Therefore, the development of (quasi) solid-state electrolytes is necessary and imperative. In this paper, the recent progress on the solid-state electrolytes and the prospects are given.

Nickel sulfides have been, for the first time, electrodeposited on transparent conductive glass by a facile periodic potential reversal (PR) technique to supersede Pt counter electrodes (CEs) of dye-sensitized solar cells (DSCs). The composition and electrochemical catalytic activity of the nickel sulfide films prepared by PR technique are different from those of the ones deposited by the commonly used potentiostatic (PS) technique. PR technique produces transparent single-component NiS, while co-deposition of Ni and NiS is found in the opaque films prepared by PS method. The nickel sulfide deposited by PR technique shows high catalytic activity for the reduction of I(3)(-) to I(-) in a DSC. DSC with the CE deposited by PR technique performs much better (6.82%) than that by PS method (3.22%), and is comparable to the device with conventional Pt coated CE (7.00%).

A novel freestanding poly (beta-hydroxyethyl methacrylate), PHEMA-based organogel electrolyte is developed simply by optimization of the solution polymerization in the same solvent as the organic electrolyte for dye-sensitized solar cells (DSCs). The room temperature ionic conductivity of the gel electrolyte is 4.54 x 10(-3) S cm(-1), and the conduction behavior can be well described by the free volume model. The quasi-solid-state dye-sensitized solar cell fabricated with this PHEMA-based polymer gel electrolyte can present high energy conversion efficiency up to 7.5%. Preliminary long-term stability test further reveals that this quasi-solid-state electrolyte exhibits good stability after 1000 h thermal test in comparison with the DSCs based on corresponding liquid electrolyte.

On the basis of the introduction of the structure and working principle of dye-sensitized solar cells(DSCs),this paper pre-sents the recent developments on the fundamental material and device studies of DSCs(e.g.photoanode,sensitizer,electrolyte and counter electrode) from the angles of cell efficiency improvement and cost reduction.Progresses of the device integration and indus-trialization of the DSCs are also reviewed as well as the existing challengers and future prospects.

We fabricated a front-side illuminated CdS/CdSe quantum dots co-sensitized solar cell based on TiO2 nanotube arrays. The freestanding TiO2 nanotube arrays were first detached from anodic oxidized Ti foils and then transferred to the fluorine-doped tin oxide to form photoanodes. An opaque Cu2S with high electrochemical activity was used as the counter electrode. A photovoltaic conversion efficiency as high as 3.01% under one sun illumination has been achieved after optimizing the deposition time of CdSe quantum dots and the length of the TiO2 nanotube arrays. It is observed that the power conversion efficiency of quantum dots sensitized solar cells from the front-side illumination mode (3.01%) is much higher than that of the back-side illumination mode (1.32%) owing to the poor catalytic activity of Pt to polysulfide electrolytes and light absorption by the electrolytes for the latter.

A flexible composite electrode, which is composed of conducting polyaniline (PANI) as electroactive material and flexible graphite (FG) as conducting substrate, has been fabricated by in situ chemical polymerization to substitute for the expensive Pt counter electrode (CE) used in dye-sensitized solar cells (DSCs). The photovoltaic parameters of DSCs are strongly dependent on the oxidation state and the thickness of the PANI film. Higher photocurrent density and efficiency have been obtained by using emeraldine PANI compared to pernigraniline. The fabrication conditions, such as reaction time and initial monomer concentration, have been investigated to control the thickness of the PANI film. With initial monomer concentration of 0.3 M and reaction time of 60 min, an optimized PANI/FG composite CE with a PANI film thickness of 330 nm has been obtained. A DSC with the composite CE shows an overall conversion efficiency of 7.36%, which is comparable to 7.45% of that with Pt electrode under the same test condition. Facile charge-transfer and low sheet resistance of the composite electrode are suggested to be responsible for high performance of the DSC using such CE.

An overview of the progress in research of dye-sensitized solar cells(DSCs),including their key materials,e.g.photoanode,dye,electrolyte and counter electrode,is presented.Meanwhile,recent development and breakthroughs concerning up-sizing technology and integration of DSCs have been reviewed.

We have successfully obtained a new figure of merit for qualifying fluorine-doped tin oxide (FTO) glass in dye-sensitized solar cells (DSCs) through two equivalent testing methods. These methods are demonstrated and applied to change the equivalent transmittance and sheet resistance of FTO glass even after the glass is assembled in DSCs. By recording the I-V characteristic of a DSC with changed equivalent transmittance and sheet resistance of FTO glass, the dependent relations between the DSC performance (short circuit current density, open circuit voltage, and fill factor) and FTO properties (transmittance and sheet resistance) are found. With these relations, the new figure of merit MTC for FTO glass is successfully defined to be in linearly increasing dependence on the efficiency of DSCs. A series of DSCs with different FTO glasses is prepared to test the effectiveness of MTC and Haacke’s figure of merit ΦTC, which has been widely used for more than 30 years. The result shows that MTC is proportional to the efficiency of DSCs, while ΦTC is not. MTC could be very useful as a guideline to greatly simplify the process of optimizing the FTO glass to improve the efficiency of DSCs.