The effect of hydroxide ion on Cd-chalcogenide/aqueous polysulfide photoelectrochemical cells
Alkali hydroxide, added to the aqueous polysulfide electrolyte in n-Cd chalcogenide/S /SUB r/ photoelectrochemical solar cells (PEC's), is is shown to be detrimental to cell performance. It is demonstrated that the added hydroxide increases visible light absorption in the polysulfide solution and decreases the solution lifetime. Even after compensation for the decrease in light tranmission by the electrolyte, added hydroxide is shown to decrease the PEC photocurrent, photovoltage, and optical-to-electrical conversion efficiency. In a cell of 1 cm path length, the transmittance at 580 nm, for solutions containing 2m K/sub 2/S, 3m sulfur, and 0, 2, 6, or 12m KOH, was, respectively, 66, 55, 44, and 37.5%. Analysis of the distribution of ionic species reveals a shift from S/sub 4/ to S/sub 3/ with increasing hydroxide. Compared to S/sub 4/, the peak absorbance of S/sub 3/ is shifted 50 nm toward the vible, causing the variation in solution spectra response with hydroxide. K/sup +/ activty measrements were interpreted as indicative of increasing ion pairing with increased added hydroxide which may adversely effect charge-transfer kinetics. A measured negative shift in polysulfide redox potential with increasing hydroxide is evidently not paralleled by a comparable shift in Cd(SeTe) flatband potential resulting in the observed decrease in open-ciruit voltage. Relative conversion efficiency for an electroplated thin film CdSe /SUB 0.65/ Te /SUB 0.35/ electrode was 36% less in polysulfide with 12m KOH compared to the PEC without added KOH. The electrode immersed in 2/2/2, 2/2/3, or 0/1,3/2 (molality KOH/K/sub 2/S/S) exhibited conversion efficiencies of 4.72, 4.80, 5.24, and 5.44, respectively, at 100mW/cm/sup 2/ tungsten-halogen lamp illumination.
- Research Organization:
- Department of Materials Research, The Weizmann Institute of Science, Rehovot
- OSTI ID:
- 5281699
- Journal Information:
- J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 132:5; ISSN JESOA
- Country of Publication:
- United States
- Language:
- English
Similar Records
The high aqueous solubility of K/sub 2/S and its effect on bulk and photoelectrochemical characteristics of Cd(SeTe)/S/sub X/= cells: II. Variation of sulfur/sulfide ratio
Combined solution effects yield stable thin-film Cd(Se,Te)/polysulfide photoelectrochemical solar cells
Related Subjects
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400 -- Electrochemistry
ABSORPTION
ABSORPTIVITY
ADDITIVES
ALKALI METAL COMPOUNDS
AQUEOUS SOLUTIONS
CADMIUM COMPOUNDS
CADMIUM SELENIDES
CADMIUM TELLURIDES
CHALCOGENIDES
CHARGE TRANSPORT
CURRENTS
DISPERSIONS
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROLYTES
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUIPMENT
FILMS
HALOGENS
HYDROGEN COMPOUNDS
HYDROXIDES
ION EXCHANGE
LIGHT BULBS
METALS
MIXTURES
NONMETALS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHOTOCURRENTS
PHOTOELECTROCHEMICAL CELLS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM HYDROXIDES
RADIATIONS
REDOX POTENTIAL
SELENIDES
SELENIUM COMPOUNDS
SOLAR EQUIPMENT
SOLUTIONS
TELLURIDES
TELLURIUM COMPOUNDS
THIN FILMS
TRANSITION ELEMENTS
TUNGSTEN
VISIBLE RADIATION