flow employed. In no way has the selection of porous structure, cell or flow geometry been optimized; these should be subjects of future investigations.
ConclusionsThis study has demonstrated the feasibility of the electrochemical reduction of EAQ dissolved in an organic solvent from an aqueous-continuous suspension flowing past an electrode. With a sufficiently high degree of turbulence, current densities and current efficiencies of industrial interest can be achieved. Although the present results are insufficient for the design or evaluation of a large-scale application of this process, it would appear that cathodic reduction of EAQ (and other water-insoluble organic compounds) in two-phase systems warrants further evaluation in the laboratory.
High efficiency (12.7%) CdSe0.68Te0.32/cesium polysulfide photoelectrochemical cells are demonstrated in this work. Crystals of the ternary alloy Cd(Se, Te) of type n type were synthesized by the traveling heater method. The nature of the polysulfide electrolyte, based on Cs polysulfide without excess hydroxide and containing small amounts of copper ions, is shown to be of particular importance in determining the cell efficiency. Reasonable output stability of the cell was obtained under accelerated tests.
High-quality Cd(Se,Te) in two compositions were synthesized using the modified Bridgman technique. The Se-rich crystals had the hexagonal structure while the Te-rich phase consisted of crystals with cubic packing. Their quality could be gauged from the high-electron mobility and their low resistivity which suited the purpose of their synthesis, i.e., for high-efficiency photoelectrochemical cells. Photoelectrochemical etching was employed, which resulted in a heavily pitted surface with the density of the etch pits exceeding 109 cm−2. Quantum efficiency of the semiconductor/aqueous polysulfide interface increased considerably after photoetching. Solar to electrical conversion efficiencies in excess of 12% were obtained. Photoluminescence spectrum was measured for the two crystals prior to and after photoetching. The emission maximum is near the calculated band gap. The decline in the luminescence intensity, after photoetching, is attributed to the corrugation of the surface and the reduced density of the donor state near the semiconductor surface, which increases the thickness of the space-charge layer (dead layer model).
It is shown that the performance of photoelectrochemical cells based on the lamellar material InSe can be considerably improved by means of a selective (photo)electrochemical etching. Whereas the cleavage Van de Waals plane (⊥ to c axis) shows little improvement, the photcurrent in the ∥ face (parallel to the c axis) is doubled (30 mA cm−2 under AM1 illumination). For n-type InSe a reverse bias (+1.5 V versus standard calomel electrode SCE) was employed during the photoetching, p-InSe electrodes were electrochemically etched by applying a forward bias (+1.5 V). In both cases, surface holes carry out the selective corrosion of the semiconductor surface which is another manifestation for the asymmetry played by holes and electrons on semiconductor surfaces. It is hoped that this finding will pave the way for the construction of high-efficiency solar cells based on a thin film made of lamellar materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.