Photoluminescence and Energy Transfer in Hybrid PbS Quantum Dots / 2D InSe Heterostructures

Hybrid nanostructures that combine zero-dimensional (0D) colloidal quantum dots (QDs) with two-dimensional (2D) transition metal dichalcogenides (TMDs) are essential for advanced optoelectronics. These systems leverage the excellent, tunable light absorption and emission of QDs, combined with the high carrier mobilities and efficient charge transport of 2D materials, to improve light absorption and photodetection efficiency through strong interfacial energy transfer. This work presents a 0D-2D hybrid system that combines Lead Sulfide (PbS) QDs with Indium Selenide (InSe) layers, a combination not previously studied. InSe stands out for its wide tunability of the band gap, shifting from direct to indirect as its thickness decreases, and for its high electron mobility, which improves device performance. The structures are created using commercially available PbS QDs combined with exfoliated p- and n-type InSe flakes. Their optical properties are examined through steady-state micro-photoluminescence (PL) spectroscopy, exploring how QD size and InSe type affect PL intensity and spectral position. Finally, the underlying energy transfer and exciton dynamics processes are investigated. This new material system is expected to offer valuable insights into carrier and energy transfer in 0D-2D systems, with potential applications in light-emitting diodes and photodetectors.