Fabrication of highly transparent CsPbBr₃ quantum-dot thin film via bath coating for light emission applications

Metal halide perovskite is not easy to form a film due to its high crystallinity, which makes it unfavourable for its application in self-luminous LED. Herein, we propose a film synthesis process for perovskite quantum dots (PeQDs) based on bath coating. The proposed method is low in cost, can be performed in an atmospheric environment at room temperature, and is suitable for the rapid mass production of closely stacked PeQDs on the deposition substrate with excellent luminous characteristics. By controlling the deposit time and rotation speed, the monolayer QD film can be achieved. The deposited monolayer QD film shows a high transmittance of up to 86% and a narrow FWHM of 18 nm. The device fabricated by monolayer QD film shows a low threshold voltage of 3 V, the maximum luminance of 150 cd/m², the maximum current efficiency of 0.085 cd/A, the maximum EQE of 0.027%, and the high color purity of 87%. Due to the above properties, monolayer QD film elements have potential in smart home appliances and wearable devices, especially AR glasses.