Yunhao Ning, Chuantong Cheng, Shuo Guan, Bao Zhang, Tuanning Liu, Di Shi, Wenqiang Liu, Beiju Huang
All inorganic CsPbBr3 perovskite nanocrystals (NCs) exhibit outstanding luminescence for optoelectronics, yet poor environmental stability severely restricts their practical deployment. As a stable derivative phase, Cs4PbBr6 can effectively improve structural stability. Nevertheless, the rational fabrication of high-quality Cs4PbBr6/CsPbBr3 hybrid NCs remains challenging owing to the lack of straightforward and scalable synthetic strategies. To overcome these hurdles, we synthesize well-defined Cs4PbBr6/CsPbBr3 hybrid NCs via a temperature-controllable continuous-flow microfluidic route. This platform precisely modulates phase composition via systematic temperature tuning across a range of 110-170 °C, producing distinct compositions from Cs4PbBr6-dominant to high-purity CsPbBr3. A direct correlation was elucidated between temperature-induced phase transformation and optical properties. The NCs synthesized at 130 °C exhibited a high photoluminescence quantum yield of 96.24% and bright 521 nm green emission. These NCs were successfully integrated into white light-emitting diodes incorporating a 478 nm blue excitation chip and K2SiF6:Mn4+ red phosphor, which demonstrated excellent color performance with a luminous efficiency of 86.3 lm W-1 and Commission Internationale de l'Éclairage coordinates of (0.2991, 0.3784). This work highlights the potential of continuous-flow microfluidics for precise phase modulation and scalable production of high-quality perovskite NCs, offering a viable route for advanced optoelectronic applications.