Enhanced performance in perovskites films by defect engineering and charge carrier transportation via pulsed laser doping of 2D MoS2

Abstract

High-performance perovskite-based optoelectronic devices require low defect density and efficient charge carrier extraction. In this paper, pulsed laser annealing was combined with two-dimensional MoS2 doping to develop an efficient strategy for the extraction of charge carriers from perovskite films with low defect density. In pulse laser annealing of perovskite films with 2D MoS2 dopant, due to their localized temperature gradients caused by fast laser annealing, the grains are much larger, and the film quality is much better than that of traditional thermal annealing perovskite films. As a result, the films absorb light better. After doping of 2D MoS2, the carrier transport in perovskite films can be increased significantly by passivating Pb-related defects through PbS coordination bonds. Additionally, the shift of the conduction band minimum (CBM) from the perovskite layer to the Au layer provides a well-matched alignment in energy levels between the perovskite and Au layers, which encourages charge carrier extraction. Moreover, the interfacial perovskite lattice moves freely during the annealing and chilling processes due to laser-induced thermomechanical momentum and weak interactions between 2D MoS2 and, thereby reducing the tensile strain in perovskite films. In addition, by improving surface hydrophobicity and relieving residual stresses, perovskite films are more humidity and thermal stable.