Synergistic size refinement and surface defect healing in CsPbBr3 quantum dots via pulsed electric current for enhanced optoelectronic performance

Realizing highly efficient, ultrasmall all-inorganic perovskite quantum dots (QDs) is pivotal for next-generation optoelectronics; however, severe surface defects that typically accompany size reduction remain a significant challenge. Herein, we achieve the synergistic regulation of particle size and surface integrity in CsPbBr 3 QDs via a rapid Pulsed Electric Current (PEC) post-treatment method. Driven by the interplay between the electric-field driving force and transient localized Joule heating, the PEC process enables precise size refinement. Concurrently, this process is hypothesized to trigger highly selective ligand desorption and a thermodynamic rearrangement of bromide ions, effectively filling the exposed surface vacancies. Through quantitative modeling, we established that the size refinement follows a logistic evolution, reaching a saturation theoretical limit of 3.73 nm, while the carrier lifetime exhibits a Gaussian response with a theoretical optimum at ∼361 V. Under optimized conditions (400 V, 60 s, 3 Hz), the mean particle size was reduced from 4.82 nm to 3.76 nm. XPS analysis confirmed an increase in the Br/Pb ratio from 2.3 to 2.5, demonstrating the effective filling of vacancies and compositional optimization. Our synergistic power-law model further reveals that the 4.4-fold enhancement in photoluminescence (PL) intensity is a collective outcome of maximized oscillator strength and defect suppression. This structure-property relationship is validated by carrier dynamics: the suppression of non-radiative channels resulted in a significantly extended average lifetime of 32.92 ns. Ultimately, these fundamental physical and optical improvements reliably translate into exceptional long-term stability under ambient conditions. This study demonstrates that the PEC-guided strategy is a simple and effective physical-field technique for modulating the structure and fundamentally enhancing the optoelectronic performance of perovskite QDs. Download: Download high-res image (209KB) Download: Download full-size image