Enhancing Internal and External Stability of Perovskite Solar Cells through Polystyrene‐Modification of the Perovskite and Rapid Open‐Air Deposition of ZnO/AlOx Nanolaminate Encapsulation

Abstract

In this study, both the internal and external stability of a p‐i‐n methylammonium lead iodide perovskite solar cell (PSC) is improved. Polystyrene (PS) is introduced into the perovskite layer to form a cross‐linked polymer‐perovskite network, which enhances the nucleation and growth of the perovskite grains. Moreover, for the first time, 60‐nm‐thick ZnO/AlOx nanolaminate thin‐film encapsulation (TFE) is deposited directly on the PSC using an atmospheric‐pressure spatial atomic layer deposition (AP‐SALD) system operated in atmospheric‐pressure spatial chemical vapor deposition (AP‐SCVD) mode. The rapid nature of AP‐SCVD enables encapsulation of the PSCs in open air at 130°C without damaging the perovskite. The PS additive improves the performance and internal stability of the PSCs by reducing ion migration. Both the PS additive and the ZnO/AlOx nanolaminate TFEs improve the external stability under standard test conditions (dark, 65°C, 85% relative humidity) by preventing water ingress. The number and thickness of the ZnO/AlOx nanolaminate layers is optimized, resulting in a water‐vapor transmission rate as low as 5.1×10‐5 g/m2/day at 65°C and 85% relative humidity. A fourteen‐fold increase in PSC lifetime is demonstrated; notably, this is achieved using polystyrene, a commodity‐scale polymer, and AP‐SCVD, a scalable, open‐air encapsulation method.This article is protected by copyright. All rights reserved.