Semiconductor Electrodes: VI . A Photoelectrochemical Solar Cell Employing a Anode and Oxygen Cathode

Abstract

A photoelectrochemical cell for conversion of light to electrical energy based on the photosensitized oxidation of water at a chemically vapor deposited, thin film, n-type TiO2 anade and the reduction of oxygen at a fuel cell-type cathode is described. The effect of load resistance on the current, cell voltage, and power was studied, and quantum and power efficiencies under short-circuit conditions for monochromatic light of about 365 nm was estimated as 26% and 1-2%, respectively. Open-circuit cell voltages of 0.89V were obtained. The cell is simple to construct and is capable oK continuous operation with no apparent deterioration in performance. * Electrochemical Society Active Member.

The Role of Energy Levels in Semiconductor‐Electrolyte Solar Cells

“…In some cases such as SnO2 (15), TiO2 (2,7,15), and WQ (16) the corresponding anodic reaction is oxygen evolution. Light excitation leads to the creation of electronhole pairs.…”

“…The holes are pushed towards the surface by the electrical field across the space-charge region and consumed for an anodic charge transfer process. [2] and [4] one obtains GaP 4-5H~O ~ Ga (OH)3 4-HsPO3 + 8H2 [5] Free energy values of Ga(OH)3 and HsPO3 are tabled in Ref. The semiconductor electrodes such as CdS (17) example this reaction can be described as (18) GaP + 6H~O 4-6P + --> Ga(OH)3 + HsPOs + 6H + [2] In the case of an oxidation of a redox system which also consumes holes the competing process is given by Red 4-P+ --> Ox [3] It seems to be useful to consider these two competing processes in view of thermodynamic data from which a theoretical value of the potential at which anodic dissolution is expected can be calculated.…”

Designing Photoelectrodes for Photocatalytic Fuel Cells and Elucidating the Effects of Organic Substrates

“…According to the Nernste quation,t he differencei np Hv alues between the anode and cathode chambersp rovides additional chemical bias for the cell (59 mV per pH unit). [44] The formic acid significantly decreased the pH value of the electrolytes in the anode chamber (pH 2.3, Ta ble 2), whereas TEOA substantially increasedt he pH value (pH 10.9). Consequently, they generated the lowest and highest V oc values, respectively.T he P max value of 0.09 mW cm À2 with TEOA is higher than most PFC performances reported in the literature.…”

n-Type Si-based photoelectrochemical cell: New liquid junction photocell using a nonaqueous ferricenium/ferrocene electrolyte

“…Conversion of light to electricity with devices called photoelectrochemical cells has been an area of considerable activity in the last 2 years (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Except for one cell that uses a p-type CdTe photocathode (12), the key element of such cells is an n-type semiconducting photoanode.…”

“…Beginning with the stimulating claims of Fujishima and Honda (18), H20 itself has been shown to be oxidized with 100% current efficiency at certain n-type semiconducting metal oxide electrodes including TiO2 (19)(20)(21)(22)(23)(24)(25)(26)(27)(28), SnO2 (29), SrTiO3 (30)(31)(32), KTaO3 (33), BaTiO3 (34), Fe2O3 (35), and W03 (9,36). Other stable oxides will likely be found, but there appear to be no nonoxide n-type semiconductors that can serve as a stable photoanode for H20 oxidation.…”