Zn(Ox,S1-x) 버퍼층 적용을 통한 Cu2ZnSnS4 태양전지 특성 향상

Abstract

This experiment investigated characteristic changes in a Cu2ZnSnS4 (CZTS) solar cell by applying a Zn (O-x, S1-x) butter layer with various compositions on the upper side of the absorber layer. Among the four single layers such as Zn(O-0.76, S-0.24), Zn(O-0.56, S-0.44), Zn(O-0.33, S-0.67), and Zn(O-0.17, S-0.83), the Zn(O-0.76, S-0.24) buffer layer was applied to the device due to its bandgap structure for suppressing electron-hole recombination. In the application of the Zn(O-0.76, S-0.24) buffer layer to the device, the buffer layer in the device showed the composition of Zn(O-0.7, S-0.3) because S diffused into the buffer layer from the absorber layer. The Zn(O-0.7, S-0.3) buffer layer, having a lower energy level (E-V) than a CdS buffer layer, improved the J(SC) and V-OC characteristics of the CZTS solar cell because the Zn(O-0.7, S-0.3) buffer layer effectively suppressed electron-hole recombination. A substitution of the CdS buffer layer by the Zn(O-0.7, S-0.3) buffer layer improved the efficiency of the CZTS solar cell from 2.75% to 4.86%.