Electrodeposition of ZnO/dye hybrid thin films for dye-sensitized solar cells

Upon cathodizing a conducting substrate in 02 saturated aqueous mixed solution of ZnCl2 and eosinY, ZnO/eosinY nano-hybrid films with high crystallinity, high transparency and grain boundary-free nano-porous structure are deposited. By soaking the films in soft alkaline solution, eosinY is completely removed without any change in film thickness. By re-loading various dyes onto the surface of these films, highly transparent ZnO films with various colors are easily obtained. The ZnO films thus loaded with various dyes are effectively applied to flexible and colorful dye-sensitized solar cells. Owing to superior properties of the films obtained under optimized conditions, the incident photon to current conversion efficiencies of the solar cells re-loaded with some kinds of organic dyes amount to 90%. Solar-to-electrical energy conversion efficiency of the DSSC employing D149 dye (Mitsubishi Paper Mills Limited) amount to 5.6% under illumination of AM1.5 simulated sun light (100 mW cm(-2)). Efficient flexible colorful solar cells by using ITO-coated PET film substrates have been fabricated. Novel application of our plastic solar cells such as wearable solar cells and the solar powered functional traffic signs has been proposed.