Short Chain Dicarboxylic Acid Mediated Synthesis of CsPbX3 (X = Cl, Br, or I) Perovskite Nanocrystals for Light-Emitting Application

The use of long-chain ligands in lead halide perovskite (LHP) nanocrystal (NC) synthesis impedes its charge transfer efficacy due to its insulating ligand environment. This report presents the first-ever in situ introduction of short-chain dicarboxylic acids instead of long-chain oleic acid for LHP NC synthesis to minimize the conductivity hindrance. As a template of a dicarboxylic acid, three-carbon-based malonic acid (MA) and ten-carbon-based sebacic acid (SA) have been used in the open-air hot injection process to synthesize highly luminescent LHP NCs covering the entire visible spectrum. MA's strong six-membered chelate passivation and superior surface coverage resulted in higher NC quality and higher PLQY for green-emitting CsPbBr3 NCs compared to the SA. In addition to NC synthesis, the formation of 2D layered perovskite nanoplates through the sebacate spacer anion as a side product of NCs has been discussed, which is unique and unprecedented. As a proof of concept, green down-converted LEDs have been fabricated by drop-casting short-chain acid-mediated CsPbBr3 NCs onto blue LEDs. The clear electroluminescence spectrum demonstrates its potential in display and lighting technologies, highlighting the promise of this synthetic approach for future device applications.