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), Vol. 132:5
- 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/subX= cells: 1. Polysulfide variation at constant sulfur/sulfide ratio
Combined solution effects yield stable thin-film Cd(Se,Te)/polysulfide photoelectrochemical solar cells
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PHOTOELECTROCHEMICAL CELLS
ADDITIVES
ELECTROLYTES
ABSORPTION
ABSORPTIVITY
AQUEOUS SOLUTIONS
CADMIUM SELENIDES
CADMIUM TELLURIDES
CHARGE TRANSPORT
ELECTRIC POTENTIAL
ELECTRODES
HALOGENS
ION EXCHANGE
LIGHT BULBS
PHOTOCURRENTS
POTASSIUM HYDROXIDES
REDOX POTENTIAL
THIN FILMS
TUNGSTEN
VISIBLE RADIATION
ALKALI METAL COMPOUNDS
CADMIUM COMPOUNDS
CHALCOGENIDES
CURRENTS
DISPERSIONS
ELECTRIC CURRENTS
ELECTROCHEMICAL CELLS
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUIPMENT
FILMS
HYDROGEN COMPOUNDS
HYDROXIDES
METALS
MIXTURES
NONMETALS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
RADIATIONS
SELENIDES
SELENIUM COMPOUNDS
SOLAR EQUIPMENT
SOLUTIONS
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENTS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400400 - Electrochemistry