Tunable Emission Peak Position and Enhanced Thermal Stability of CsPbBr₃ Quantum Dots via TMCS Ligand Exchange

All-inorganic lead halide perovskite quantum dots (QDs), featuring high photoluminescence quantum yield, narrow full width at half maximum, and solution processability, show great promise for high-color-purity displays and optoelectronic devices. Their emission peak position and stability are highly dependent on the surface coordination environment, and achieving controllable color tuning while maintaining stability without altering the primary synthetic route remains a critical challenge. Herein, we propose a facile solution-phase post-treatment strategy using TMCS, which can react with the oleate ligands on the CsPbBr₃ QD surface while providing abundant Cl^- ions, thereby leading to partial halide exchange, achieving continuous tuning of the emission wavelength from 499 nm to 473 nm. The appearance of new absorption peaks in the FTIR spectra indicated the successful introduction of TMCS and the in situ generation of HCl, which led to surface etching and passivation. After being heated at 40 °C for 6 h, the TMCS-50 sample retained 39% of its initial photoluminescence intensity, while the pristine CsPbBr₃ QD sample retained only 8%, demonstrating that TMCS treatment significantly improves the thermal stability of the CsPbBr₃ QDs.