Highly stable and Efficient Perovskite Solar Cells Based on FAMA‐Perovskite‐Cu:NiO Composites with 20.7% Efficiency and 80.5% Fill Factor
Yousheng Wang, Tahmineh Mahmoudi, Yoon‐Bong Hahn
Abstract
Abstract To solve critical issues related to device stability and performance of perovskite solar cells (PSCs), FA 0.026 MA 0.974 PbI 3− y Cl y ‐Cu:NiO (formamidinium methylammonium (FAMA)‐perovskite‐Cu:NiO) and Al 2 O 3 /Cu:NiO composites are developed and utilized for fabrication of highly stable and efficient PSCs through fully‐ambient‐air processes. The FAMA‐perovskite‐Cu:NiO composite crystals prepared without using any antisolvents not only improve the perovskite film quality with large‐size crystals and less grain boundaries but also tailor optical and electronic properties and suppress charge recombination with reduction of trap density. A champion device based on the composites as light absorber and Al 2 O 3 /Cu:NiO interfacial layer between electron transport layer and active layer yields power conversion efficiency (PCE) of 20.67% with V OC of 1.047 V, J SC of 24.51 mA cm −2 , and fill factor of 80.54%. More importantly, such composite‐based PSCs without encapsulation show significant enhancement in long‐term air‐stability, thermal‐ and photostability with retaining 97% of PCE over 240 d under ambient conditions (25–30 °C, 45–55% humidity).