Gold Doping of HgTe Colloidal Quantum Dots for High-Performance Infrared Photodetectors

HgTe colloidal quantum dots (CQDs) have gained significant interest due to their extremely wide spectral response and excellent solution processability, making them promising candidates for the next-generation infrared photodetectors. However, the limited availability of p -type HgTe CQDs poses a significant challenge to device construction. In this study, a room-temperature process is identified – one based on a cation exchange process – for the preparation of p -type Au-doped HgTe CQDs. The resultant Au-doped HgTe CQDs exhibit tunable p -type doping, enhanced defect passivation, and improved doping homogeneity than conventional Ag-doped HgTe CQDs. By using Au-doped HgTe CQDs as the hole transport layer, high-performance p -on- n photodiodes are demonstrated, where a record external quantum efficiency (EQE) of 58.8% at ≈1.6 µm and a specific detectivity above 10 12 Jones are successfully demonstrated. This work shows the promise of heterovalent doping in CQDs for advancing infrared optoelectronic devices and is poised to pave the way for further exploration of innovative doping strategies in nanomaterials.