Organic dye-doped thin films for wavelength conversion and their effects on the photovoltaic characteristics of CdS/CdTe solar cell

For the improvement of the conversion efficiency of CdS/CdTe solar cells by applying the wavelength conversion properties, the spectroscopic studies of the fluorescent laser dye Rhodamine 6G (Rh6G)-doped into polyvinylbutyral (PVB) and polymethylmethacrylate (PMMA) were carried out. It was found that all the photoluminescence excitation (PLE) spectra below 540 nm were effectively converted to photoluminescence (PL) spectra in the wavelength region above 550 nm where the solar cell possessed a high spectral quantum efficiency. The external quantum efficiencies of PVB:Rh6G and PMMA:Rh6G films were estimated to be 0.9 +/- 0.05 and 0.4 +/- 0.1, respectively. When the PVB:Rh6G film was placed on the top of the CdS/CdTe solar cell. both short-circuit current and conversion efficiency increased by 11% compared with the cell with no film.