Removing Metallic Lead Defects in the Surface Layer of Lead Halide Perovskite Films Using a Pulsed UV Laser for Enhancing the Performance of Perovskite Solar Cells
Mengyu Fu, Xueyan Shan, Shimao Wang, Xiao Zhao, Ruhua Tao, Libing You, Zanhong Deng, Xiaodong Fang, Gang Meng
Abstract
Metallic lead (Pb 0 ) defects, commonly formed during the deposition process of lead halide perovskite films, are one of the important factors affecting the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). Therefore, eliminating or passivating the Pb 0 defects in the perovskite light-absorbing layers is imperative and effective for enhancing PSC performance. Here, a simple, rapid, and noncontact approach based on a pulsed UV laser utilizing its advantages of high photon energy and shallow penetration depth has been proposed for removing Pb 0 defects on the surface of perovskite films. The X-ray photoelectron spectroscopy spectrum indicated that the peaks of Pb 0 disappeared completely after UV laser irradiation with a laser energy density of 2.26 mJ cm –2, suggesting that the Pb 0 defects on the surface layer of perovskite films have been effectively removed by fine-tuning the energy density of the UV laser. Furthermore, the average PCE of PSCs increases from 18.65 to 20.72%.