Optimization on Low-Dimensional Components of Quasi-2D Perovskite Films for Deep Blue Light-Emitting Diodes
Shuai Yuan1, Zhao-Kui Wang1*, Lei-Xin Xiao2, Chun-Feng Zhang2, Sheng-Yi Yang1, Bing-Bing Chen3, Hui-Ting Ge1,Qi-Sheng Tian1, Yan Jin1, Liang-Sheng Liao1*
1Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123, China.
2 National Laboratory of Solid State Microstructures，School of Physics and Collaborative Innovation Center of Advanced Microstructures Nanjing University, Nanjing, Jiangsu 210093, China
3Department of Energy Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, China
Compared to efficient green and near-infrared light-emitting diodes (LEDs), less progress has been made on deep-blue perovskite LEDs. They suffer from inefficient domain [various number of PbX6- layers (n)] control, resulting in a series of unfavorableissues such as unstable color, multi-peak profile and poor fluorescence yield. Here, we report a strategy involving a delicate spacer modulation for 2D perovskite films via an introduction of aromatic polyamine molecules into the perovskite precursor. With low-dimensional components engineering, the n1 domain, which shows non-radiative recombination and retarded exciton transfer, is significantly suppressed. Also, the n3 domain, which representsthe population of emission species, is remarkably increased. The optimized quasi-2D perovskite film presentsblue emission from n3 domain (peak at 465 nm) with aphotoluminescence quantum yield (PLQY) as high as 77 %. It enables the corresponding perovskite LEDs to deliver stable deep blue emission (CIE (0.145, 0.05)) with an external quantum efficiency (EQE) of 2.6 %. The findings in this work provide further understanding on the structural and emission properties of quasi-2D perovskites, which pave a new route to design deep-blue emissive perovskite materials.