期刊論文

標題 Density Functional Study of the Interfacial Electron Transfer Pathway for Monolayer-Adsorbed InN on the TiO2 Anatase (101) Surface
學年 95
學期 1
出版(發表)日期 2006/12/01
作品名稱 Density Functional Study of the Interfacial Electron Transfer Pathway for Monolayer-Adsorbed InN on the TiO2 Anatase (101) Surface
作品名稱(其他語言)
著者 林志興
單位 淡江大學化學學系
出版者
著錄名稱、卷期、頁數 J. Phys. Chem. B110, pp.23460-23466
摘要 Density functional theory (DFT) in connection with ultrasoft pseudopotential (USP) and generalized gradient spin-polarized approximations (GGSA) is applied to calculate the adsorption energies and structures of monolayer-adsorbed InN on the TiO2 anatase (101) surface and the corresponding electronic properties, that is, partial density of states (PDOS) for surface and bulk layers of the TiO2 anatase (101) surface and monolayer-adsorbed InN, to shed light on the possible structural modes for initial photoexcitation within the UV/vis adsorption region followed by fast electron injection through the InN/TiO2 interface for an InN/TiO2-based solar cell design. Our calculated adsorption energies found that the two most probable stable structural modes of monolayer-adsorbed InN on the TiO2 anatase (101) surface are (1) an end-on structure with an adsorption energy of 2.52 eV through N binding to surface 2-fold coordinated O (Ocn2), that is, InN−Ocn2, and (2) a side-on structure with an adsorption energy of 3.05 eV through both N binding to surface 5-fold coordinated Ti (Ticn5) and In bridging two surface Ocn2, that is, (Ocn2)2−InN−Ticn5. Our calculated band gaps for both InN−Ocn2 and (Ocn2)2−InN−Ticn5 (including a 1.0-eV correction using a scissor operator) of monolayer-adsorbed InN on the TiO2 anatase (101) surface are red-shifted to 1.7 eV (730 nm) and 2.3 eV (540 nm), respectively, which are within the UV/vis adsorption region similar to Gratzel's black dye solar cell. Our analyses of calculated PDOS for both surface and bulk layers of the TiO2 anatase (101) surface and monolayer-adsorbed InN on the TiO2 anatase (101) surface suggest that the (Ocn2)2−InN−Ticn5 configuration of monolayer-adsorbed InN on the TiO2 anatase (101) surface would provide a more feasible structural mode for the electron injection through the InN/TiO2 interface. This is due to the presence of both occupied and unoccupied electronic states for monolayer-adsorbed InN within the band gap TiO2 anatase (101) surface, which will allow the photoexcitation within the UV/vis adsorption region to take place effectively, and subsequently the photoexcited electronic states will overlap with the unoccupied electronic states around the lowest conduction band of the TiO2 anatase (101) surface, which will ensure the electron injection through the InN/TiO2 interface. Finally, another thing worth our attention is our preliminary study of double-layer-adsorbed InN on the TiO2 anatase (101) surface, that is, (Ocn2)2−(InN)2−Ticn5, with a calculated band gap red-shifted to 2.6 eV (477 nm) and a different overlap of electronic states between double-layer-adsorbed InN and the TiO2 anatase (101) surface qualitatively indicated that there is an effect of the thickness of adsorbed InN on the TiO2 anatase (101) surface on both photoexcitation and electron injection processes involved in the photoinduced interfacial electron transfer through InN/TiO2. A more thorough and comprehensive study of different layers of InN adsorbed in all possible different orientations on the TiO2 anatase (101) surface is presently in progress.
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語言 英文
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期刊性質 國內
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國別 中華民國
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