Continuous-flow synthesis of doped all-inorganic perovskite nanocrystals enabled by a microfluidic reactor for light-emitting diode application

Abstract

All-inorganic perovskite nanocrystals (AIPNCs) possess the advantages of narrow emission spectrum, high quantum efficiency of luminescence and tunable luminescence position, which show a broad application prospect in the fields of optoelectronic materials and devices. Ion doping can tune their pristine crystal structures and luminescent properties or endow the AIPNCs with additional functionalities. Herein, a microfluidic reactor is designed to produce the Ce3+-doped AIPNCs based on the continuous-flow reaction. The mechanism of the flow synthesis of Ce3+-doped AIPNCs is the efficient physical mixing of the precursor ions in the confined micro-channel, the reaction nucleation of crystal seeds in the poor solvent and the crystal growth of the doped AIPNCs along the flow direction. The synthesis process can be on-line monitored by an optical fiber absorption spectrometer and an optical fiber fluorescence spectrometer. The doping concentration of Ce3+ can be facilely controlled by changing the flow parameters in the microfluidic reactor, and the highest value reaches 1%. The Ce3+ doping can improve the photoluminescence efficiency and the stability of the AIPNCs. The Ce3+-doped CsPbBr3 AIPNCs can be used to manufacture green light-emitting diodes (LEDs) with a high color purity of 93.3% and white LEDs with correlated color temperature (CCT) of 10,436 K, CIE color coordinates of (0.261, 0.317) and color-rendering index (CRI) of 72.1. The continuous and controllable synthesis of AIPNCs by microfluidic reactor opens up new avenues for the application of the high-performance optoelectronic materials and devices.