High-performance optoelectronics enabled by solution-based sintering of perovskite nanocrystals†

Perovskite nanocrystals have emerged as promising constituents for optoelectronic applications due to their exceptional and tunable properties and their scalable synthesis. However, their integration into devices faces challenges such as defects, poor carrier transport, and ligand interference. We present a liquid-in-liquid impingement process that achieves the mechanical coalescence of lead–bromide perovskite nanocrystals into large, free-standing flakes under ambient conditions. This approach leverages localized shear forces generated during impingement to achieve nanocrystal sintering, ligand removal, and solvent exchange. Microscopic analysis reveals the formation of large surface-sintered domains that overcome previous issues of defectiveness and environmental stability. This process results in significant improvements of the sintered nanocrystal properties compared to random perovskite assemblies. We demonstrate a significant decrease in trap density leading to enhanced chemical stability, charge transport and radiative charge recombination. Enhancements in carrier mobility enable the fabrication of photodetectors with exceptional response speed and sensitivity, surpassing conventional methods. These findings highlight the potential of liquid impingement processing for advancing perovskite-based optoelectronics through scalable and efficient nanocrystal assembly.