Counter-Doping Effect by Trivalent Cations in tin-based Perovskite Solar Cells.

Sn-based perovskite solar cells normally show low open circuit voltage due to serious carrier recombination in the devices, which can be attributed to the oxidation and the resultant high p-type doping of the perovskite active layers. Considering the grand challenge to completely prohibit the oxidation of Sn-based perovskites, a feasible way to improve the device performance is to counter-dope the oxidized Sn-based perovskites by replacing Sn 2+ with trivalent cations in the crystal lattice, which however has been rarely reported. Here, we present the introduction of Sb 3+ , which can effectively counter-dope the oxidized perovskite layer and improve the carrier lifetime. Meanwhile, Sb 3+ can passivate deep-level defects and improve carrier mobility of the perovskite layer, which are all favourable for the photovoltaic performance of the devices. Consequently, the target devices yield a relative enhancement of the power conversion efficiency (PCE) of 31.4% as well as excellent shelf-storage stability. This work provides a novel strategy to improve the performance of Sn-based perovskite solar cells, which can be developed as a universal way to compensate for the oxidation of Sn-based perovskites in optoelectronic devices. This article is protected by copyright. All rights reserved.