Postsynthetic Size Focusing via Digestive Ripening in HgTe Quantum Dots

Size uniformity in colloidal quantum dots (CQDs) critically influences their electronic properties. However, achieving precise size control remains challenging for mercury chalcogenide systems. We demonstrate that a postsynthetic reheating treatment with the addition of dodecanethiol (DDT) ligands, consistent with a digestive ripening mechanism, effectively narrows the size distribution of HgTe CQDs from 12% to 6%, accompanied by enhanced crystallinity and sharper absorption features. Significantly, this improved structural uniformity leads to a 10-fold reduction in intrinsic carrier density from 2.3 × 10¹⁸ to 1.8 × 10¹⁷ cm^-3. Our theoretical analysis reveals that such carrier density reduction, combined with band-edge engineering, could enable quantum dot operation at significantly elevated temperatures up to 230 K with simple thermoelectric cooling. This work establishes a straightforward postsynthetic approach to refine mercury telluride CQDs, providing a valuable quality control strategy that could potentially enhance the yield and reliability in commercial IR CQD mass production.