Improvement of the conversion efficiency of solar cell by rare earth ion

For the purpose of improvement of the conversion efficiency of solar cells by applying the effect of the wavelength conversion of a rare earth (RE) ion, photoluminescence (PL) and photoluminescence excitation (PLE) spectra of the Sm-doped KMgF3 crystal were investigated. It was found that all the PLE spectra below 500 nm were effective to convert to PL spectra above 540 nm and that the solar cell possessed high spectral response. When a thin disc crystal of KMgF3:Sm was placed on the top of CdS/CdTe solar cell as a precursor for wavelength conversion, both the maximum output power and the conversion efficiency increased by 5% as compared with the case of a pure KMgF3 crystal. The present results are compared with the experimental results of wavelength conversion solar cells performed until now, and some features are discussed.