Understanding the Role of Crown Ether Functionalization in Inverted Perovskite Solar Cells

Inverted p-i-n structure perovskite solar cells (PSCs) have attracted considerable attention in consideration of high-efficiency, long-term stability, and cost reduction, which represent the key challenges in advancing the commercialization of PSCs. In order to address the issue of defect-related nonradiative recombination, we enhanced the interfacial passivation between the perovskite layer and electron transfer layer with crown ether derivatives in p-i-n PSCs. By a combination of first-principles calculations, photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra, and grazing-incidence wide-angle X-ray scattering (GIWAXS) characterization, we provided an understanding of the passivation mechanism and obtained an efficiency of 23.3% in NiOx-based p-i-n PSCs, which lowered the nonradiative recombination with 25% of the voltage losses. Furthermore, the unencapsulated PSCs kept 92% of the initial efficiency following 1224 h of aging, which demonstrated remarkable long-term stability. The inverted structure with interfacial passivation could provide great potential for high-efficiency and stable PSC designs and promote the commercialization of PSCs.