Next Generation Organic Photovoltaics as ^|^ldquo;Artificial Membrane for Photo-energy Conversion^|^rdquo;

Next-generation solar cells based on new concepts and/or novel materials are currently attracting wide interests. The solar cell is recognized as “Artificial Membrane for Photo-energy Conversion”. Among new types of solar cells, dye-sensitized solar cell (DSSC) have received much attention as the low-cost solar cell. In our study, panchromatic photoelectric conversion up to around 1000 nm has been accomplished by the use of new sensitizer. We prepared the mechanical stack tandem solar cell showing a high overall power conversion efficiency (η) of about 12%. On the other hand, polymer-sensitized solar cell (PSSC) were constructed as hybrid organic solar cell by the use of novel soluble polythiophene derivatives with hydrophilic anchoring units. The PSSC sensitized with two types of the polymers yielded higher IPCE values in the visible region because of dual-sensitization. As for the other hybrid organic photovoltaics, surface complexes formed of TiO2 with dicyanomethylene compounds (TCNX) were used for the solar cells where the charge separation occurs directly by the charge-transfer transitions. At the last part, a three-electrode solar rechargeable battery, namely “energy-storable dye-sensitized solar cell (ES-DSSC)” was described.