Probing encapsulation-induced changes in 2D/3D perovskite heterostructures for perovskite solar cells

Abstract

Two-dimensional/three-dimensional (2D/3D) perovskite heterostructures have been extensively employed for effective interfacial defect passivation, enabling highly efficient perovskite solar cells (PSCs). At the same time, encapsulation plays a vital role in ensuring the long-term stability of PSCs toward commercialization. However, conventional lamination-based encapsulation processes involve elevated temperatures and mechanical pressure, and the resulting thermal and mechanical stress on the 2D/3D heterostructure within the device remains largely underexplored. Herein, we investigated how encapsulation affects 2D/3D perovskite heterostructures by probing the photoluminescence properties of films before and after encapsulation. In particular, we compare encapsulation effects for (100)- and (111)-oriented perovskites using various 2D passivants to form 2D/3D heterostructures. The results suggest that encapsulation-induced degradation in 2D/3D heterostructures based on conventional mixed-oriented perovskites primarily originates from those formed on (100)-oriented perovskites, whereas those on (111)-oriented perovskites are more tolerant to the thermal lamination conditions used during encapsulation. This work provides critical insights into perovskite structural evolution during the encapsulation process, advancing their path toward stable commercial applications.