Material Dimensionality Effects on Electron Transfer Rates Between CsPbBr3 and CdSe Nanoparticles

Films containing mixtures of zero- or two-dimensional nanostructures (quantum dots or nanoplatelets) were prepared in order to investigate the impacts of dimensionality on electronic interactions. Electron transfer from CsPbBr3 to CdSe was observed in all of the mixtures, regardless of particle dimensionality, and characterized via both static and transient absorption and photoluminescence spectroscopies. We find that mixtures containing nanoplatelets as the electron acceptor (CdSe) undergo charge transfer more rapidly than those containing quantum dots. We believe the faster charge transfer observed with nanoplatelets may arise from the extended spatial area of the CdSe nanoplatelets and/ or the continuous density of acceptor states that are present in nanoplatelets. These results bolster the use of one- or two-dimensional nanomaterials in the place of zero-dimensional quantum dots in the design of related optoelectronic devices such as solar cells, light-emitting diodes, and photocatalysts and further offer the prospect of fewer required hopping events to transport carriers due to the larger spatial extent of the particles.