Broadband Optical Enhancement in Strongly Coupled Perovskite–PbS Nanostructures

Extending the absorbance range of perovskite nanoparticles to the near-infrared (NIR) region is essential for expanding their optoelectronic applications. In this study, PbS nanoparticles (NPs) were conjugated with CsPbBr₃ NPs via a PbSO₄ matrix, forming hybrid nanostructures with optical responses spanning from the visible to the NIR region achieving a total photoluminescence quantum yield (PLQY) of 66%. The PbSO₄ matrix enables the formation of well-organized 1D nanorods, ensuring a consistent and close proximity between the two types of NPs. Temperature-dependent time-resolved photoluminescence measurements revealed efficient charge transfer from the CsPbBr₃ NPs to the PbS NPs. Surface photovoltage spectroscopy and ambient photoemission spectroscopy were used to construct the energy-level diagram of this unique system, confirming the strong coupling between the two semiconductors. This hybrid approach offers a strategy to conjugate dissimilar semiconductors without the need for lattice matching.