High Performance Self Powered Infrared Photodetectors Based on PbSe Quantum Dots With Enhanced Charge Transport Through Hybrid Bulk Heterojunction Engineering

Nanocomposite engineering offers an effective strategy to overcome charge recombination and transport limitations in colloidal quantum dot photodetectors. In this work, high-performance self-powered near-infrared photodetectors were fabricated using PbSe QDs integrated into hybrid bulk-heterojunction architectures with poly(3-hexylthiophene) (P3HT) and polyvinylcarbazole (PVK) as polymer matrices. Colloidal PbSe QDs with high crystallinity and strong NIR absorption were synthesized via a controlled solution process. While pristine PbSe devices suffer from trap-assisted recombination and limited carrier transport, incorporation of polymer-assisted HBJ structures significantly enhances charge separation, carrier mobility, and interfacial coupling. Among the fabricated devices, the PbSe:PVK photodetector exhibits superior performance, achieving a maximum responsivity of 17.89 A/W, an ON/OFF ratio of 7.86 × 10², and a detectivity of 2.28 × 10¹⁴ Jones under 980 nm illumination in self-powered mode, along with an extended linear dynamic range of 63.45 dB. Density functional theory (DFT) calculations reveal improved interfacial electronic redistribution and stronger band-edge coupling in the PbSe:PVK system, while TCAD simulations demonstrate enhanced optical generation and carrier extraction across the device architecture. The combined experimental and multiscale simulation results confirm that polymer-mediated interfacial engineering effectively suppresses recombination losses and optimizes carrier dynamics.