Chalcogenide quantum dots (QDs) are established as promising materials for white-light-emitting applications because of their wide surface defect emission. However, the limited understanding about the origin of defect emission poses challenges in attaining efficient white-light emission. Herein, high pressure is introduced to strengthen the interaction between the different types of ligands and QDs, as well as enables in situ observation of surface traps passivation that contributes in emission control. Under pressure, both defect emission and band-edge emission in the CdS QDs can be selectively enhanced by more than an order of magnitude through treatment with X-type and Z-type ligands, respectively. Our findings identify that surface hole traps predominantly contribute to defect emission, whereas non-radiative recombination is primarily associated with surface electron traps. Aiming at the goal of servicing ambient science through high-pressure research, based on this proposed mechanism, an energysaving ‘neutral’ white light with human-eye friendly color rendering index of 86 is achieved by tuning the defect emission through further eliminating surface Cd sites. This study endows high pressure as an efficient tool to elucidate the defect origin of chalcogenide QDs under ambient conditions, and pays the way for precise control over white-light emission through materials design applied in solid-state lighting.
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