Cu+-doped lead-free double perovskite quantum dots for enhancing the photovoltaic performance of carbon-based Cs2AgInCl6 perovskite solar cells.

Abstract

Lead-free double perovskite solar cells (PSCs) have received widespread attention because of their non-toxic nature and three-dimensional structure. However, their photovoltaic efficiency is limited by their large bandgap, including indirect or direct forbidden. Herein, Cu+ ions are incorporated into Cs2AgInCl6 double perovskite quantum dots, following which the bandgap is effectively decreased from 3.6 to 2.9 eV. Meanwhile, a facile method of drop-coating is employed to fabricate Cs2AgInCl6 films and carbon electrodes. A carbon electrode derived from a by-product of the cane sugar industry (molasses) is used to replace the expensive hole-transport materials and metal electrodes. A 0.5% Cu+-doped Cs2AgInCl6, device fabricated using carbon-based PSCs with a stacked-architecture achieves a power conversion efficiency of 1.77%, which is 2.9 times higher than that of the original device, and displays a better stability compared with that of the control one. This study provides guidance for preparing PSCs using a low-cost, facile strategy.