Photo-induced interfacial electron transfer between the dye and semiconductor nanocrystalline has important applications in solar cells, quantum dot devices and photocatalytic hydrogen generation. Chemical and electronic properties of the species undergoing photoinduce electron transfer are determined largely by their static and transient structures of the ground and excited states. Directly visualizing these structures is necessary for molecular/material designs for targeted functions, therefore, realizing the rational designs of solar cells. X-ray transient absorption or laser-initiated, time-resolved X-ray absorption spectroscopy (XTA or LITR-XAS) has been used to probe the photo-induced structural changes at dye-nanoparticle interface. Two examples will be presented: Ru(dcbpy)2(NCS)2 and Os(dcbpy)2(CN)2 adsorbed to TiO2 nanoparticle surface. The photoexcited Ru and Os complexes inject electrons into the conduction band of TiO2, leading to an interfacial charge separated state, (TiO2)n-/(dye)+. The electronic configuration as well as the internuclear distance changes of metal complexes in the charge separation state has been observed. These measurements demonstrate a significant potential of using LITR-XAS to study the interfacial phenomena at surface of nonmaterial in solar fuel generation.
ASJC Scopus subject areas
- Chemical Engineering(all)