Enhancement of luminous properties and stability of CH3NH3PbBr3 perovskite quantum dots using a low-cost, environmentally friendly and multisite passivation strategy

CH3NH3PbBr3 perovskite quantum dots (PeQDs) have demonstrated excellent performance and are promising for optoelectronic applications. However, poor stability caused by surface defects severely limits their further development. In this work, cheap, green Tartaric acid (Ta) was introduced as a multisite passivator for the synthesis of CH3NH3PbBr3 PeQDs by ligand-assisted reprecipitation at room temperature, and the effect of Ta on the luminous properties and stability of CH3NH3PbBr3 PeQDs was investigated. The hydroxyl group of Ta can anchor Br- of PbBr64- octahedra, reducing the Br vacancy by reducing surface Br loss, and the carboxyl group can form a coordination bond with Pb2+, all contributing to reducing surface defects, inhibit heavy metal leakage, reduce toxicity and improve luminous properties and stability. The results showed that the FWHM (full width at half maxima) of the Ta-modified PeQDs was 19 nm, PLQY reached 88.24 % and showed bright fluorescence for 100 days at room temperature. Ta-modified PeQDs-based white LED (WLED) emitted cold white light, with ultrahigh luminous efficiency of 121.57 lm/W, color gamut of 127 % of the National Television System Committee (NTSC) standard and high operate stability. Our work provides new ideas for low-cost preparation of perovskite devices with high optoelectronic performance.