Interfacial charge-transfer transitions in SnO₂ functionalized with benzoic acid derivatives

Abstract

First observation of interfacial charge-transfer transitions in SnO2.

Linkage Dependence of Interfacial Charge-Transfer Transitions in ZnO: Carboxylate versus Sulfur Linker

“…). − In contrast to the diversity of organic compounds, inorganic semiconductors available for ICTT remain limited to a few kinds of titanium oxide semiconductors (TiO 2 , SrTiO 3 , and BaTiO 3 ). , Accordingly, the exploration of ICTT in other kinds of inorganic semiconductors is a high-priority issue not only for the fundamental research of ICTT but also for the applications. Recently, we have reported ICTTs in ZnO and SnO 2 nanoparticles, which have been widely employed in solar cells and photocatalytic reactions and chemical sensing devices. − In ZnO nanoparticles, ICTT bands appear in the visible region by adsorption of aromatic thiol compounds such as benzenethiol (BT) via the sulfur atom. , In the same paper, we also reported that ZnO nanoparticles show almost no ICTT band in the visible region by adsorption of phenol in contrast to aromatic thiols . This result is consistent with that reported by Li et al, in which they observed negligibly small ICTT bands in ZnO nanoparticles adsorbed with phenol derivatives .…”

Interfacial Charge-Transfer Transitions in Weakly Coupled TiO2 Complexes with Aromatic Monothiols for Visible-Light Photocatalytic Reactions

“…1−17 Because of these features, ICTTs have attracted increasing interest as a new visible-light absorption mechanism and a direct photoinduced charge-separation mechanism for photoenergy conversions such as photovoltaic conversion 9,18−23 and photocatalytic reactions 24−34 and for chemical/biological sensing based on direct visualization, 2,3,35−38 surface enhanced Raman scattering, 39−41 and visible-light circular dichroism 42 of colorless organic compounds. So far, ICTTs have been studied intensively in strongly coupled complexes of inorganic semiconductors (TiO 2 , 1−17 SrTiO 3 , 43 BaTiO 3 , 43,44 ZnO, 45−47 SnO 2 , 48 etc.) with aromatic or π-conjugated organic molecules that possess anchoring groups (−OH, [1][2][3][4][5][6]43,44 −SH, 7,8,45,46 −COOH, [9][10][11][12][13]47,48 −NH−, 14,15,30,31 etc.).…”

“…Particularly, surface coordination complexes of wide band-gap inorganic semiconductors such as TiO 2 with organic compounds possessing anchoring groups characteristically show interfacial charge-transfer transitions (ICTTs), which enable the absorption of visible light for colorless organic molecules and direct photoinduced charge separation at the organic–inorganic interfaces, as shown in Figure . − Because of these features, ICTTs have attracted increasing interest as a new visible-light absorption mechanism and a direct photoinduced charge-separation mechanism for photoenergy conversions such as photovoltaic conversion ,− and photocatalytic reactions − and for chemical/biological sensing based on direct visualization, ,,− surface enhanced Raman scattering, − and visible-light circular dichroism of colorless organic compounds. So far, ICTTs have been studied intensively in strongly coupled complexes of inorganic semiconductors (TiO 2 , − SrTiO 3 , BaTiO 3 , , ZnO, − SnO 2 , etc.) with aromatic or π-conjugated organic molecules that possess anchoring groups (−OH, − ,,…”

“…So far, ICTTs have been studied intensively in strongly coupled complexes of inorganic semiconductors (TiO 2 , − SrTiO 3 , BaTiO 3 , , ZnO, − SnO 2 , etc.) with aromatic or π-conjugated organic molecules that possess anchoring groups (−OH, − ,, −SH, ,,, −COOH, − ,, −NH–, ,,, etc.). Accordingly, the basic and applied research of ICTTs has focused on the strongly coupled complexes, which can be isolated without remarkable desorption of the adsorbed molecules.…”

Interfacial Charge-Transfer Transitions between TiO2 Nanoparticles and Benzoic Acid Derivatives

“…Recently, ICTT has been reported in several kinds of wide band gap oxide semiconductors (TiO 2 , SrTiO 3 , BaTiO 3 , ZnO, SnO 2 , etc.) chemically linked to π-conjugated compounds possessing chemical linkers (−OH, −SH, −COOH, and −NH−), as shown in Figure a. − ,,− Among them, surface coordination complexes of TiO 2 nanoparticles with aromatic compounds linked via a carboxylate group are one of the most important ICTT systems for photoenergy conversions. Recently, we reported that ICTT takes place between TiO 2 nanoparticles and organic dyes bearing a carboxy anchoring group and plays a crucial role in light harvesting in the red to near-IR region in DSSCs .…”