Quantum Dot Enabled Perovskite Thin Film with Enhanced Crystallization, Stability, and Carrier Diffusion via Pulsed Laser Nanoengineering

Abstract The temperature control at the material interface, such as grain boundaries, is critical for defect density, and phases, which are important for high‐performance perovskite‐based optoelectronic devices. However, it is challenging to fine‐tune the microstructures in perovskite films with well‐controlled grain structure, interface defects, porosity, phase structure, and strains, simultaneously. Here, pulsed laser technology is combined with carbon quantum dots (CQDs) into perovskite absorbers with pore‐free, less defect, high crystallinity, enhanced absorption, low stress, and phase‐stabilized microstructures. Due to laser–CQD interaction‐induced grain boundary microstructure changes, perovskite films can be fabricated with much larger grains (>10 times) than those after thermal annealing. As CQDs are embedded to passivate grain, this leads to reduced grain boundary barrier at the interface, which significantly improve the carrier transportation in perovskite films. The shift of perovskite band to vacuum energy level leads to remarkable improvement of carrier extraction efficiency and lifetime, leading to much higher mobility of photogenerated carriers and diffusion length (>1 μm). The laser‐induced thermomechanical momentum significantly enhances crystal interface with hydrophobic perovskite film, resulting in much less residual tensile stress by 20 times and excellent stability. Pulsed‐laser‐assisted QD additive engineering has great potential for perovskites films under harsh conditions.