Beneficial effect of alloy disorder on the conversion efficiency of ZnO/ZnxCd1−xSe coaxial nanowire solar cells

Abstract

Ternary Zn_xCd_1−xSe alloys are potential materials for sensitized photovoltaic devices because of their tunable bandgaps and band structures. In this work, random deposition of Cd and Zn was realized by the co-evaporated chemical vapor deposition method to tune the distribution of the lattice constant and the mixing of the structural phase to the utmost, and thus release the misfit stress by the self-adaption mechanism. As a result, the coaxial nanowire with an approximate composition x of 0.5 exhibited the high crystal quality and the long nonequilibrium carrier lifetime because of the alloy disorder effect. The corresponding photo-electrochemical cell acquired a power conversion efficiency of 3.68%. This work paves the way for the design and development of high-efficiency coaxial solar cells based on ternary or multi-component alloys.