Surface Modification of All-Inorganic Perovskite Nanocrystals for Light-Emitting Diode Applications: Fine-Tuning the Composition During Mechanosynthesis

Abstract

Perovskite nanocrystals (PNCs) have emerged as promising alternatives to traditional quantum dots like indium phosphide (InP) and cadmium selenide (CdSe) due to their facile synthesis and compatibility with scalable methods such as mechanosynthesis. Unlike conventional solution-based techniques, mechanosynthesis uses mechanical force to drive reactions, enabling temperature-independent, eco-friendly, and large-scale production. However, controlling nucleation and crystal growth in this method remains a challenge, often resulting in poor optical properties, limiting its use in light-emitting diodes (LEDs). In this study, we present a compositional tuning strategy during mechanosynthesis to enhance the surface quality and optoelectronic properties of CsPbBr3 PNCs. By varying the feed ratios of cesium, lead, and bromide precursors, we synthesized Pb-excess (LE) and Cs-excess (CE) PNCs with distinct surface characteristics. While the LE PNCs showed a higher photoluminescence quantum yield (PLQY) (88.39%) than CE PNCs (43.27%), the CE-based devices exhibited superior electroluminescence, achieving a maximum external quantum efficiency (EQE) of 1.12% (vs. 0.26% for LE) and luminance of 4029 cd m−2 (vs. 584 cd m−2 for LE). These results demonstrate that ligand density on the nanocrystal surface can be modulated via precursor composition, offering a simple yet effective route to fabricate high-performance LEDs via mechanochemical synthesis. © 2026 Wiley-VCH GmbH.