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Structural Effects on the Incident Photon-to-Current Conversion Efficiency of Zn Porphyrin Dyes on the Low-Index Planes of TiO2
journal contribution
posted on 2017-01-19, 17:20 authored by Ryo Ide, Yamato Fujimori, Yukihiro Tsuji, Tomohiro Higashino, Hiroshi Imahori, Hideki Ishikawa, Akihito Imanishi, Ken-ichi Fukui, Masashi Nakamura, Nagahiro HoshiThe
structural effects of substrates on the incident photon-to-current
conversion efficiency (IPCE) of Zn porphyrin (ZnP) dyes (ZnP-ref,
YD2, and ZnPBAT) have been studied on well-defined single-crystal
surfaces of rutile TiO2 (TiO2(111), TiO2(100), and TiO2(110)). IPCE of ZnP-ref depends
on the structure of the substrates remarkably: TiO2(100)
< TiO2(110) < TiO2(111). IPCE of ZnP-ref/TiO2(111) is 13 times as high as that of ZnP-ref/TiO2(100) at 570 nm. YD2 and ZnPBAT also give the highest IPCE on TiO2(111). The relative coverages of the porphyrin dyes give the
following order: TiO2(111) < TiO2(110) <
TiO2(100). This order is opposite to that of IPCEs. The
orientation of the dyes is predicted using density functional theory
calculations on simplified models of TiO2 surfaces. The
highest IPCE on TiO2(111) is attributed to the high rate
of electron transfer through the space due to the fluctuation of the
tilt angle of the adsorbed dyes.