Achieving highly efficient antisolvent- and annealing-free NIR perovskite light-emitting diodes by optimizing the gradient of preheating

The antisolvent approach is widely used to make high-quality and uniform perovskite films, as well as to improve the performance of perovskite light-emitting diodes (PeLEDs) and other optoelectronic perovskite devices like solar cells and photodetectors. However, the use of antisolvents necessitates very careful control and introduces toxicity into the fabrication methods, limiting their large-scale commercial application. In this article, we propose an approach that simply replaces the traditional antisolvent method while also shortening the fabrication process by utilizing the substrate preheating method in which the preheating gradient is adjusted and N,N-dimethylacetamide (C4H9NO) is incorporated as the sole solvent in BA2MAn-1PbnI3n+1 perovskite precursor solution to obtain antisolvent-free perovskite films. Fine-tuning the suitable preheating gradient resulted in the formation of high quality antisolvent-free perovskite films with enhanced optoelectronic properties. As a consequence, antisolvent-free PeLEDs with an optimal preheating gradient demonstrates the highest external quantum efficiency of 15.89% and a brightness of 400.16 W sr-1 m-2, considerably outperforming the reference devices, which only exhibit a maximum efficiency of 8.01% with a brightness of 111.74 W sr-1 m-2. Therefore, the proposed approach to fabricate antisolvent-free PeLEDs would not only facilitate the process but also reduce their manufacturing cost for industrial applications as well as academic research. Johan and colleagues demonstrated antisolvent- and annealing-free PeLEDs by modulating the substrate preheating gradient. The strategy is a viable alternative to the traditional antisolvent method for promoting high-quality perovskite films.