The impact of metal cations on photochemical properties of hybrid heterostructures with infinite alkaline-earth metal oxide clusters
The donor-acceptor (D-A) hybrid heterostructures are an emerging class of hybrid complexes with potential applications in current optoelectronic technologies. To achieve a high photoinduced charge-carrier generation and separation in a heterostructure, a common strategy is the fabrication of continuous or bicontinuous structures by the crystallization of the semiconductive donor and acceptor tectons at the molecular level. So far, only few such heterostructures have been fabricated, and most of which involved in the unstable and narrow-band metal halides. In this paper, we extended these unique hybrid heterostructures into continuous alkaline-earth metal oxide clusters. The combination of naphthalene diimide (NDI) tecton bearing four carboxylates at two extremities with Ca2+ (or Sr2+) cations led to two isomorphous D-A hybrid heterostructures with infinite 1-D carbon-doped alkaline-earth metal oxide clusters and X-aggregated NDI dimers as the electron donors and acceptors. Due to the different metal cation in inorganic clusters, they exhibited diametrically opposite photochromic sensitivities and photocatalytic activities. To better rationalize them, a plausible photoinduced electron transfer process for the D-A hybrid heterostructures with photoactive acceptors has been developed.