Photochemical conversion of solar energy. Annual progress report, January 1, 1976--December 31, 1976. [Iron--thiazine]

Technical Report · Tue May 31 04:00:00 EDT 1977

OSTI ID:5359460

Lichtin, N N

Thin-layer, totally-illuminated (TI-TL) iron-thiazine photogalvanic cells were investigated. The energy diagram for the interface between SnO/sub 2/ and iron-thionine solutions was determined. The potentials for TH/sub 4//sup 2 +//TH/sub 2//sup +/ and Fe/sup 3 +//Fe/sup 2 +/ fall in the band gap region of SnO/sub 2/. Output of the iron-thionine TI-TL SnO/sub 2//Pt cell with a number of new binary and ternary solvent systems was investigated. The best was a 10 w/w percent solution of non-ionic surfactant Brij-35 (n-C/sub 12/H/sub 25/(OC/sub 2/H/sub 4/)/sub 23/OH in 25 v percent CH/sub 3/CN-75 v percent H/sub 2/O. V/sub oc/ x I/sub sc/ was approximately 35 percent higher in this solvent than in 50 v/v percent CH/sub 3/CN. Investigation of other dyes and redox quenchers did not reveal any photoredox system as efficient in the TI-TL SnO/sub 2//Pt cell as iron-thionine. Iron-thionine TI-TL SnO/sub 2//Pt cells employing SnO/sub 2/ which had been reduced by flowing hydrogen at 400/sup 0/C gave V/sub oc/ and I/sub sc/ 20 to 30 percent higher than from cells with unreduced V/sub oc/. TiO/sub 2/ reduced by flowing H/sub 2/ at 600/sup 0/C had R/sub s/ approximately 4K..cap omega../sq and was a very promising anode in the TI-TL iron-thionine cell: V/sub oc/ = 246 mV. Currents were approximately 20 percent those obtained with SnO/sub 2/ anodes, possibly because of high electrode resistance. Compound anodes fabricated by sputtering TiO/sub 2/ onto Pt or SnO/sub 2/ onto transparent, conductive (R/sub s/ approximately 1..cap omega../sq) Cd/sub 2/SnO/sub 4/ were promising. Cd/sub 2/SnO/sub 4/ was chemically unstable in direct contact with acid solutions. Substantial sensitization to the blue of iron-thiazine TI-TL SnO/sub 2//Pt cells has been demonstrated. Rhodamine 6G was the most effective sensitizer studied. Sunlight engineering efficiency for power conversion has been increased twofold with thionine and almost sixfold with azure A. Rhodamine 6G substantially increases (TH/sub 4//sup 2 +/)/sub pss/, decreases the lifetime of the photostationary state and accelerates degradation of SnO/sub 2/ electrodes.

• Research Organization: Boston Univ., Mass. (USA). Dept. of Chemistry
• OSTI ID: 5359460
• Report Number(s): NSF/RANN/SE/AER-72-03579/A05/76/4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
AMINES
AZINES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DISPERSIONS
DYES
EFFICIENCY
ELECTROCHEMICAL CELLS
ELECTROCHEMISTRY
ELECTRODES
ELECTRON TRANSFER
ELEMENTS
FABRICATION
HETEROCYCLIC COMPOUNDS
IRON
METALS
MIXTURES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
PHOTOGALVANIC CELLS
PLATINUM
PLATINUM METALS
REAGENTS
REDOX REACTIONS
RESEARCH PROGRAMS
SENSITIZERS
SOLUTIONS
TESTING
THIONINE
TIN COMPOUNDS
TIN OXIDES
TRANSITION ELEMENTS
VOLTAMETRY