Determination of the nature of electronic transitions in the complexes of rhodamine dye and CdS clusters

Abstract

The phenomenon of transfer of excitation energy between quantum dots and organic dyes on their surface was considered by the TD-DFT method. Complexes of [RhB − Cd4S1] 7+ and [RhB − Cd13S4] 19+ were studied. It was shown that in the dye complex [RhB] + with cadmium
sulfide clusters, new bands appear in the long-wave region of the spectrum, with a significant part of them having a low intensity. This circumstance can be explained by a significant increase in the dipole moment of the system in the formation of complexes. It is also shown that it is possible to observe intense charge transfer bands. The increase in the positive charge of the cadmium sulfide
cluster, as a consequence of the increase in the number of cadmium ions Cd2+ , leads to a change in the direction of the transfer of the photoexcited electron. Also, an analysis was made of the nature of molecular orbitals participating in intense transitions. These data indicate the possibility of charge transfer from clusters of cadmium sulfide to cation dye and vice versa.