A first-principles study of polycyclic aromatic hydrocarbon-mediated PbS QD/2D BP 0D/2D hybrid-dimensional systems

Broadband infrared photodetectors hold great potential for applications such as military, machine vision, industrial processes, and medical imaging. However, the widespread adoption of current high-performance detectors based on epitaxial growth is hindered by their high production costs. The integration of colloidal quantum dots (QDs) with two-dimensional (2D) materials offers a low-cost and efficient alternative for next-generation photodetectors. The excellent light responsiveness of QDs combined with the high carrier mobility of 2D materials is expected to result in superior optoelectronic performance of hybrid-dimensional heterostructures. In this study, we propose a PbS QD/boron phosphide (BP) monolayer-based zero-/two-dimensional (0D/2D) hybrid-dimensional system. Through first-principles calculations, we explored its electronic structure, carrier transport, and optoelectronic properties. The results reveal that BP possesses excellent electron mobility and dynamic stability, showcasing its potential in phototransistor applications. Furthermore, we designed and optimized polycyclic aromatic hydrocarbons (PAHs) as ligands for PbS QDs and found that the introduction of electron-withdrawing groups can significantly modulate the energy-level structure and carrier dynamics of the system. When constructing PbS QD-PAHs/BP heterostructures, the optimal design achieves a continuous type-II band alignment, significantly enhancing electron injection rates while suppressing carrier recombination. Through an in-depth analysis of molecular coupling mechanisms and π-π interactions, we revealed the critical role of PAHs in strengthening the interfacial coupling between PbS QDs and BP. This study provides theoretical guidance for designing high-performance 0D/2D hybrid optoelectronic materials and lays a foundation for the practical application of broadband photodetectors.