Charge separation is known to occur in heterostructure nanocrystals with type II alignment. Transfer rates have been inferred from ultrafast measurements, but other elements relevant to this process, such as the role of the solvent and the internal degrees of freedom, are still poorly understood. The present study investigates temperature and solvent effects on the optical properties of the charge-separated state in CdSe/CdTe collinear nanorods. The importance of the surrounding medium in the steady state photoluminescence is suggested both in the solvent and temperature studies. The latter also provides evidence that a charge-separated bound state is formed at the interface of the two materials, while states where electron and hole behave as free carriers are only accessible through an activated process in which the interfacial exciton is dissociated. Finally, using a dipole-dielectric continuum model, we found that the optical properties of the charge-separated state in these nanocrystals change as a function of solvent polarity.
A Hamiltonian based approach using spatially localized projection operators is introduced to give precise meaning to the chemically intuitive idea of the electronic energy on a quantum subsystem. This definition facilitates the study of electronic energy transfer in arbitrarily coupled quantum systems. In particular, the decomposition scheme can be applied to molecular components that are strongly interacting (with significant orbital overlap) as well as to isolated fragments. The result defines a consistent electronic energy at all internuclear distances, including the case of separated fragments, and reduces to the well-known Förster and Dexter results in their respective limits. Numerical calculations of coherent energy and charge transfer dynamics in simple model systems are presented and the effect of collisionally induced decoherence is examined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.