High-Efficiency Solar Cells from Extremely Low Minority Carrier Lifetime Substrates Using Radial Junction Nanowire Architecture

Abstract

Currently, a significant amount of photovoltaic device cost is related to its requirement of high quality absorber materials, especially in the case of III−V solar cells. Therefore, a technology that can transform a low-cost, low minority carrier lifetime material into an efficient solar cell can be beneficial for future applications. Here, we transform an inefficient p-type InP substrate with a minority carrier lifetime less than 100 ps into an efficient solar cell by utilizing a radial p−n junction nanowire architecture. We fabricate a p-InP/n-ZnO/AZO radial hetero junction nanowire solar cell to achieve a photovoltaic conversion efficiency of 17.1%, the best reported value for radial junction nanowire solar cells. The quantum efficiency of ∼95% (between 550 and 750 nm) and the short-circuit current density of 31.3 mA/cm2 are among the best for InP solar cells. In addition, we also perform an advanced loss analysis of the proposed solar cell to assess different loss mechanisms in the solar cell.