Study on the efficient PV/TE characteristics of the self-assembled thin films based on bismuth telluride/cadmium telluride

Abstract

Solar radiation has a spectral distribution ranging from short wavelengths (200–800 nm, visible part) to long wavelengths (800–3000 nm, heat part). Cadmium telluride and bismuth telluride are well known photovoltaic (PV) and thermoelectric (TE) materials, respectively. CdTe converts light energy into electricity and Bi₂Te₃ converts heat into electricity. To effectively use the entire solar spectrum for energy conversion, a new type of solar cell based on a Bi₂Te₃/CdTe composite in a core/shell structure was designed and prepared using a wet chemical method. X-ray diffraction and high-resolution transmission electron microscopy confirmed the formation of Bi₂Te₃/CdTe in a core/shell structure with high crystallinity. Bi₂Te₃ nanoparticles function as built-in nanoscale electron generators to convert heat into electricity and CdTe functions as a photovoltaic cell. The efficiency of the thin film solar cell device was found to be 2.5% at room temperature and 4.8% when exposed to sunlight. The combined PV and TE modules resulted in an overall power conversion efficiency of 4.8%.