Nonradiative Energy Transfer between CsPbBr₃ Nanoplatelets and AgInS₂ Quantum Dots

Nonradiative energy transfer mechanisms, such as Förster resonance energy transfer (FRET), from a donor semiconductor to an acceptor may compete with the detrimental Auger recombination process within the semiconductor, thereby advancing their optoelectronic applications. While the FRET phenomenon has been intensively investigated in numerous perovskite and dye molecule pairs, FRET between thickness-controlled two-dimensional (2D) perovskite nanoplatelets (NPls) and zero-dimensional (0D) quantum dots (QDs) remains elusive. This work reports a thickness-driven FRET between CsPbBr₃ NPls and AgInS₂ QDs in a 2<i>D</i>/0D nanocomposite. The CsPbBr₃/AgInS₂ nanocomposite was fabricated using a simple postsynthetic approach and then characterized using X-ray diffraction and transmission electron microscopy. Using steady-state and time-resolved optical spectroscopic investigations, we show extremely efficient FRET between 2-monolayer (ML) CsPbBr₃ NPls and AgInS₂ QDs, having a FRET efficiency over 90%, while very poor FRET is observed between the 6 ML CsPbBr₃/AgInS₂ pair. We explain such thickness dependency by considering the spectral overlap between the donor (CsPbBr₃) and the acceptor (AgInS₂), which can be precisely controlled by altering the NPl thickness. The thickness-driven FRET efficiency between the CsPbBr₃ NPls/AgInS₂ QDs may lead to the design of a library of 2D perovskite-0D QD donor-acceptor pairs for optoelectronics.