New low-temperature approach for forming high performance CH3NH3PbI3 solar cells with good productivity and stability (Conference Presentation)

Abstract

Recently, researchers have focused more to design highly efficient flexible perovskite solar cells (PVSCs), which enables the implementation of portable and roll-to-roll fabrication in large scale. Here, we demonstrated that vacuum-assisted thermal annealing can be used to control the composition, morphology, and thus the quality of the perovskite films formed from the precursors of PbCl2 and CH3NH3I. Using our vacuum-assisted thermal annealing approach to completely remove the chlorine byproduct, pure, pore-free planar CH3NH3PbI3 films with enhanced morphology can be readily formed for high efficiency PVSCs with high stability and reproducibility. In addition, we will report new room temperature approaches for forming PVSCs. Regarding the hole transport layer (HTL), NiOx is a promising material for candidate for fabricating efficient PVSCs. Here, we demonstrate the flawless and surface-nanostructured NiOx film from a simple and controllable room-temperature solution process. Meanwhile, we will propose a new room temperature scheme formation of perovskite films with the features of PbI2 residue-free, large grain-sizes, and highly crystalline. We further layout the design rules for the broad, rational extension of our scheme to form high-quality perovskite films. Using our approach, a room-temperature processed PVSC is obtained with no hysteresis, high power conversion efficiency of about 18%, which is the best of the PVSCs fabricated by low-temperature techniques to date. Additionally, the device is very stable with performance maintance of 95% after 1000 hours. This work contributes to the large-sale and low-cost production of PVSCs with high device performances.