Ultrafine Cu2ZnSnS4 quantum dots functionalized TiO2 nanotube arrays for potential optoelectronic applications

Abstract

Tremendous progress has been made in power conversion efficiency (PCE) of thin-film photovoltaics over the past few years, yet most current high-efficient photoactive layer usually contains rare or toxic elements accompanied by expensive and complicated vacuum processes, which increases the cost and limits the scope of the applications in the long run. Here we present a synergistic effect of quantum effect of an earth-abundant and low toxic ultrafine Cu2ZnSnS4 (CZTS) quantum dots (QDs) and low charge recombination in one dimensional TiO2 nanotube arrays for optoelectronic devices. By ligands exchange, the as-obtained ultrafine CZTS QDs have been robustly anchored to a highly ordered TiO2 nanotube arrays (TNAs) to be served as a function layer in a simple QDs sensitized solar cells. Such ultrafine CZTS QDs based solar cells exhibit significant enhancement up to 457% in PCE compared to that of CZTS QDs with larger size. The CZTS QDs functionalized TNAs has also shown excellent charge transport capability with lower recombination rate than QDs sensitized TiO2 nanoparticles and it is expected to be used as a low-cost environment-friendly function layer for various potential optoelectronic applications.