Chalcogenide photoelectrodes

Cd-chalcogenides (CdS, CdSe, CdTe) are among the most studied materials as photoelectrodes in a photoelectrochemical cell (PEC) (1,2 /3,4). Interest in such PEC s stems from the fact that, in aqueous polysulfide or polyselenide solutions, a drastic decrease in photocorrosion is observed, as compared to other aqueous solutions, while reasonable conversion efficiencies can be attained. 

Nucleophilic adsorbates have also yielded interesting system improvements. Lamellar chalcogenides exhibit a strong sensitivity towards dissolved Lewis bases. For example, the photoelectrochemical behaviour of WSc2 and MoSe2 photoelectrodes dramatically improved after exposure to solutions that contained pyridines or ethylenediaminetetraacetic acid, respectively (Canfield and Parkinson, 1981 Fan... 

For certain purposes, mixed chalcogenides are desirable, for example, Cd(S, Se) for photoconductors sensitive to a range of visible wavelengths of light, and Cd(Se, Te) which has been proposed as photoelectrode material in photoelectro-chemical cells, with an extended spectral response compared with CdSe, and greater stability than CdTe.3... 

The kinetic approach has been to allow another desired redox process to occur at a much faster rate than the photocorrosion reaction [13]. Other attempts to minimize the photocorrosion has been to coat the photoelectrode surface with layers such as Se [24] and protective conductive polymer films [25], and to search for alternate low band gap semiconductors [26]. Extensive reviews on the performance and stability of cadmium chalcogenides include those by Cahen and coworkers, 1980 [27] and Hodes, 1983 [28]. Etching of photoelectrode surface has been recognized and... 

In 1976, the first regenerative PECs with substantial and sustained solar to electrical conversion efficiency were demonstrated. These PECs are based on n-type cadmium chalcogenide (S, Se or Te) electrodes immersed in aqueous polychalcogenide electrolytes. The cells were introduced by Hodes, Cahen, and Manassen (31), Wrighton and coworkers [32], and Heller and Miller [33] and were capable of converting up to 7% of insolation to electrical energy. Most investigations of these systems focused on solid-state and interfacial aspects of these PECs and photodriven oxidation of polysulfide at the photoelectrode was represented ... 

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