Title: N-type molybdenum diselenide-based photoelectrochemical cells: evidence for Fermi level pinning and comparison of the efficiency for conversion of light to electricity with various solvent/halogen/halide combinations. Interim technical report

Abstract

Interfacial energetics for n-type MoSe/sub 2/ (E(g) = 1.4 eV, direct) and photoelectrochemical conversion of light to electrical energy in the presence of X(n)(-)/X(-) (X = Cl, Br, I) have been characterized in CH/sub 3/CN electrolyte solution. Data for MoSe/sub 2/ in H/sub 2/O/I/sub 3/(-)/I(-) are included for comparison, along with a comparison of MoSe''-based cells with MoS/sub 2/- (E(g) = 1.7 eV, direct) based cells. Cyclic voltammetry for a set of reversible (at Pt electrodes) redox couples whose formal potential, E(o), spans a range -0.8 to +1.5 V vs. SCE has been employed to establish the interface energetics of MoSe/sub 2/. For the redox couples having E(o) more negative than approximately -0.1 V. vs. SCE, we find reversible electrochemistry in the dark at n-type MoSe/sub 2/. When E (o) is somewhat positive of -0.1 V vs. SCE we find that oxidation of the reduced form of the redox couple can be effected in an uphill sense by irradiation of the n-type MoSe/sub 2/ with = or > E(g) light; the anodic current peak is at a more negative potential than at Pt for such situations. The extent to which the photoanodic current peak is more negative than at Ptmore » is a measure of the output photovoltage for a given couple. For E(o) more positive than approximately +0.7 V vs. SCE it would appear that this output photovoltage is constant at approximately 0.4 V. For a redox couple such as biferrocene (E(o)(BF(+)/BF = +0.3 V vs. SCE) we find a photoanodic current onset at approximately -0.2 V vs. SCE; a redox couple with E = 1.5 V vs. SCE shows an output photovoltage of 0.43 V under the same conditions.« less

Authors:

Schneemeyer, L F; Wrighton, M S

Publication Date:

1980-07-18

Research Org.:

Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Chemistry

OSTI Identifier:

6890421

Report Number(s):

AD-A-088161

DOE Contract Number:  

N00014-78-C-0630

Resource Type:

Technical Report

Country of Publication:

United States

Language:

English

Subject:

14 SOLAR ENERGY; PHOTOELECTROCHEMICAL CELLS; EFFICIENCY; ELECTROCHEMISTRY; ALKANES; ANODES; CYANIDES; ELECTRICITY; ELECTRODES; HALIDES; HALOGENS; MOLYBDENUM COMPOUNDS; MOLYBDENUM SELENIDES; N-TYPE CONDUCTORS; PHOTOCHEMICAL REACTIONS; REDOX REACTIONS; SELENIDES; SOLVENTS; CHALCOGENIDES; CHEMICAL REACTIONS; CHEMISTRY; ELECTROCHEMICAL CELLS; ELEMENTS; EQUIPMENT; HALOGEN COMPOUNDS; HYDROCARBONS; MATERIALS; NONMETALS; ORGANIC COMPOUNDS; SELENIUM COMPOUNDS; SEMICONDUCTOR MATERIALS; SOLAR EQUIPMENT; TRANSITION ELEMENT COMPOUNDS; 140505* - Solar Energy Conversion- Photochemical, Photobiological, & Thermochemical Conversion- (1980-)