Improving the photovoltaic performance and stability of perovskite solar cells through PEG-modified hole transport layers

Perovskite solar cells (PSCs) have developed rapidly, however, the high cost of materials, inadequate device stability, and stringent manufacturing conditions still hinder their large-scale commercialization. In this study, we demonstrate that polyethylene glycol (PEG) modification of the hole transport layer enhances the efficiency (with power conversion efficiency (PCE) increasing from 8.41 to 9.01%) and stability. After continuous illumination for 16 days under unencapsulated conditions, the device maintains 89% of its initial efficiency. The incorporation of PEG reduces defects in the hole transport layer, decreases the non-radiative recombination rate of charge carriers, and minimizes the damage caused by moisture to the perovskite light-absorbing layer, thereby improving the overall performance of the PSCs. The materials used are inexpensive and easy to fabricate, and the entire process is conducted in an ambient atmosphere.