Impact of Oxidative Aging on the Performance of Colloidal Quantum Dot-Sintered PbSe Infrared Detectors

Semiconductor inks based on colloidal quantum dots (QDs) enable low-cost, scalable fabrication of thin-film devices through solution-based techniques such as inkjet and screen printing. While these approaches have been widely demonstrated for light-emitting pixel arrays in display technologies, they also offer significant potential for the fabrication of sensor arrays for imaging. This capability is particularly attractive for detectors operating at longer infrared wavelengths, a spectral region currently dominated by expensive epitaxially grown semiconductors. Here, we demonstrate this approach using solution-processed quantum dots to fabricate photoconductive films of polycrystalline lead selenide, an important semiconductor material that enables uncooled mid-infrared photodetection. We investigate the impact of oxidative aging of QDs, a previously overlooked process that significantly enhances the sensitivity of QD-sintered polycrystalline films. An optimal QD aging window is identified that maximizes device performance, yielding a room-temperature specific detectivity of 6.75 × 109 Jones at a peak wavelength of 3.5 μm and a modulation frequency of 1 kHz, comparable to those of commercial detectors.