Amidation-Mediated Growth of Low-Defect Colloidal ZnO Quantum Dots and Their Ultraviolet Photodetector Applications

Colloidal zinc oxide quantum dots (ZnO CQDs) are key material for solution-processed optoelectronics, but their performance is severely limited by high intrinsic defect densities. Here, we report a low-temperature organometallic synthesis approach that achieves layer-by-layer growth of low-defect ZnO CQDs through cyclic amidation reactions. This method enables precise control over growth kinetics, yielding ZnO and ZnO: Al CQDs with strong excitonic UV emission and near-complete suppression of deep-level defect emission. When implemented in UV photodetectors, these low-defect CQDs deliver devices with ultralow dark current, responsivity of 5 A·W –1, subsecond response times, and a high detectivity of 2.6 × 10 13 Jones, outperforming conventional ZnO CQD-based devices. This work provides critical insights into the design and synthesis of low-defect, size-controlled ZnO CQDs, paving the way for their application in optoelectronic devices.