ZnO/CdS/CuInSe2 thin-film solar cells with improved performance

TLDR

A 15% conversion efficiency milestone marks a key achievement in thin‑film photovoltaic development. Co‑evaporation with controlled rate and substrate temperature produces large‑grained, strongly 〈112〉‑oriented CuInSe2 with low porosity. The authors achieve a record 14.8% efficient single‑junction ZnO/CdS/CuInSe2 cell, the highest reported, by enhancing CuInSe2 and heterojunction properties to lower recombination and raise Voc and fill factor.

Abstract

An important milestone in the development of photovoltaic thin-film solar cells is the achievement of 15% conversion efficiency. This letter describes the highest efficiency single junction thin-film cell reported to date. An active area efficiency of 14.8% is obtained with the cell structure n-ZnO/n-CdS/p-CuInSe2 deposited on a soda-lime glass substrate. The current achievements are due to improved properties of the CuInSe2 layer and the heterojunctions compared to previously reported results. The rate and substrate temperature profiles used during the coevaporation process yield a relatively large-grained material with very strong 〈112〉 orientation and low porosity. This results in reduced recombination rates, hence higher open circuit voltage and fill factor.