Design of a high efficiency ultrathin CdS/CdTe solar cell using back surface field and backside distributed Bragg reflector

Abstract

A high efficiency CdS/CdTe solar cell was designed with a reduced CdTe absorber-layer thickness and a distributed Bragg reflector (DBR) as an optical reflector and a ZnTe layer as back surface field (BSF) layer. Simulation results showed that with combination of DBR and BSF layers and 0.3 µm thick CdTe, the conversion efficiency was increased about 3.2% as compared with a reference cell (with 4 µm thick CdTe layer). It was also shown that the efficiency can be increased up to 6.02% by using a long carrier lifetime in the absorber layer. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.062 V, a short-circuit current density of 24.64 mA/cm², and a fill factor of 81.3%, corresponding to a total area conversion efficiency of 21.02%.

Photocurrent application of Zn-doped CdS nanostructures grown by thermal evaporation method

“…Therefore, it is a suitable material for visible light absorption and it is one of the best candidates as window material for heterojunction solar cells to avoid the recombination of photogenerated carriers, which improves the solar cells efficiency [2][3]. In addition, it can be used as lightemitting diodes (LEDs), optoelectronic devices, photocatalytic and so on [4][5][6][7][8].…”

Design of a high efficiency CdS/CdTe solar cell with optimized step doping, film thickness, and carrier lifetime of the absorption layer

“…Polycrystalline CdTe films have high optical absorption coefficient and are normally used in a CdS/CdTe heterojunction configuration. The most important parameter that affects photon absorption is thickness of the CdTe layer [1]. A ZnTe layer is usually used as a back surface barrier to repel the electrons at the CdTe/ZnTe heterojunction and thus decrease the loss of carriers at the back contact (due to presence of a higher band-gap layer at the back) [2].…”

Ultrathin Crystalline Silicon Heterojunction Solar Cell Integrated on Silicon-on-Insulator Substrate

“…The BSF structure has been widely used to reduce the carrier recombination at the rear surface and improve the efficiency in other solar cells [6], [7]. In our SHJ solar cell, the thickness of p-type c-Si layer is only 10 μm, which is much smaller than that needed to absorb all the light in c-Si.…”