Photosensitization and the Photocurrent Switching Effect in Nanocrystalline Titanium Dioxide Functionalized with Iron(II) Complexes: A Comparative Study

Abstract

Selected iron(II) complexes (ferrocene, ferrocenylboronic acid, hexacyanoferrate(II)) have been used as photosensitizers of titanium dioxide. Various types of electronic interactions between the surface complex and the semiconducting support are reflected in different yields of photocurrent generated upon visible-light irradiation and different efficiencies of the photosensitization effect. The studied systems, showing the photocurrent switching upon changes of electrode potential and energy of photons (the PEPS effect), are good models of simple photoelectrochemical logic devices. The mechanism of photosensitization and photocurrent switching is discussed with respect to the type of surface-complex-support interaction. Quantum-mechanical calculations support the proposed mechanisms.

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2‐Based Nanomaterials

“…Drawing on the fundamental studies on dye sensitization of other wide bandgap semiconductors (ZnO, SnO 2 ) in the 1960s [55][56][57][58][59], attaching visiblelight-absorbing organic dyes to the surface of TiO 2 [60,61] has led to fabrication of regenerative dye-sensitized solar cells with the overall solar conversion efficiencies exceeding 10% [62][63][64]. Other sensitization approaches utilize chromophores like semiconductor quantum dots [65][66][67][68][69][70], plasmonic metal nanocrystals [71][72][73][74][75], simple coordination compounds like chloroplatinate (IV) complexes [29,32,76] or ferrocyanide ions [77][78][79], stable polymeric compounds [38,39,[80][81][82][83], or metal ions (Cu 2+ , Fe 3+ ) grafted onto the TiO 2 surface [84,85]. In contrast to these surfaceconfined sensitization protocols, bulk-doping of TiO 2 has also attracted significant interest.…”

A Simple Unimolecular Multiplexer/Demultiplexer

“…[19] Here we show that the reversible acid/base switching of the absorption and photoluminescence properties of a fluorophore as simple as 8-methoxyquinoline in solution can form the basis for molecular 2:1 multiplexing and 1:2 demultiplexing with a clear-cut digital response. [19] Here we show that the reversible acid/base switching of the absorption and photoluminescence properties of a fluorophore as simple as 8-methoxyquinoline in solution can form the basis for molecular 2:1 multiplexing and 1:2 demultiplexing with a clear-cut digital response.…”

Multifunctional gold nanoparticles as signal transducers for fabrication of 1:2 molecular demultiplexer

“…Molecular computers have much computing performance that may be hard to reach with silicon-based devices. Although the components of molecular computer are different from that of traditional microelectronic circuit, several efforts have been devoted to the development of molecular systems mimicking the operation of electronic logic gates and circuits over the past decade [6][7][8][9][10][11]. Recently, demultiplexer, an important electronic logic device, has been mimicked at the molecular level, providing a new molecular switch.…”