In recent years, solution-processed metal halide perovskite-type light-emitting diodes have made significant progress in the near-infrared, red and green three colors, and their external quantum efficiency (EQEs) exceeds 20%. However, the perovskite-type LED has poor blue emission performance, which limits its application in full-color display and white light illumination. Although the EQEs of blue perovskite LEDs have also reached 10%, these works are mainly concentrated in the sky blue area and cannot meet the standards of the National Television Standards Committee (NTSC). The application of perovskite-type light-emitting diodes (LEDs) in the field of lighting and display requires high-efficiency and stable deep blue light-emitting characteristics. However, due to the phase segregation of mixed halide perovskites and the difficulty of synthesizing high-quality monohalide dark blue perovskite nanocrystals with traditional methods, this is difficult to achieve. Researchers from Nanjing University of Technology and other units demonstrated that an anti-solvent treatment can promote the in-situ preparation of perovskite nanocrystals. The LED device has a stable electroluminescence (EL) peak at 465 nm, and the peak external quantum efficiency and peak current efficiency are 2.4% and 2.5cdA−1, respectively. This work provides a simple and feasible method for changing the size of perovskite nanocrystals. Literature link: In Situ-Fabricated Perovskite Nanocrystals for Deep-Blue Light Emitting Diodes, J. Phys. Chem. Lett., 2020 https://pubs.acs.org/doi/10.1021/acs.jpclett.0c03120 Original link: https://www.toutiao.com/i6910555707532132877/