High-Performance Solution-Processed Quantum Dot Infrared Photodetectors via Interface Engineering with MXenes

Infrared (IR) photodetectors are crucial for a range of applications, including night vision, optical communication, and environmental monitoring. However, their effectiveness is often hindered by low charge transport and interfacial losses in colloidal quantum dot (CQD)-based designs. MXenes, known for their high metallic conductivity, adjustable surface terminations, and excellent optical transparency, present a unique opportunity to improve interfaces for better optoelectronic performance. In this work, Ti3C2Tx MXene via interface engineering for PbS CQD IR photodetectors, in which it functions as an electrode, transport layer, and interfacial modifier is systematically investigated. As a result, an ultrahigh responsivity of 1032.37 A/W with a specific detectivity of 1.12 × 1013 Jones and an external quantum efficiency of 1.311 × 105 % are obtained from photodetector ITO/ZnO/Ti3C2Tx/PbS/MoO3/Ti3C2Tx under 1 μW/cm2 980 nm illumination. Our finite difference time domain (FDTD) simulations further support and provide a physical basis for our experimental results, indicating that dual MXene incorporation significantly enhances optical field confinement and absorption within the PbS CQD layer. Thus, it illustrates that MXene-enabled interface engineering and optical coupling can establish an effective design paradigm for high-performance, solution-processed infrared photodetectors, effectively bridging the gap between quantum materials and practical optoelectronics.