Postsynthetic\nSize Focusing via Digestive Ripening\nin HgTe Quantum Dots

Size uniformity in colloidal quantum dots (CQDs) critically\ninfluences\ntheir electronic properties. However, achieving precise size control\nremains challenging for mercury chalcogenide systems. We demonstrate\nthat a postsynthetic reheating treatment with the addition of dodecanethiol\n(DDT) ligands, consistent with a digestive ripening mechanism, effectively\nnarrows the size distribution of HgTe CQDs from 12% to 6%, accompanied\nby enhanced crystallinity and sharper absorption features. Significantly,\nthis improved structural uniformity leads to a 10-fold reduction in\nintrinsic carrier density from 2.3 × 10<sup>18</sup> to 1.8 ×\n10<sup>17</sup> cm<sup>–3</sup>. Our theoretical analysis reveals\nthat such carrier density reduction, combined with band-edge engineering,\ncould enable quantum dot operation at significantly elevated temperatures\nup to 230 K with simple thermoelectric cooling. This work establishes\na straightforward postsynthetic approach to refine mercury telluride\nCQDs, providing a valuable quality control strategy that could potentially\nenhance the yield and reliability in commercial IR CQD mass production.