Interfacial charge-transfer and excited-state deactivation processes in doped and undoped cadmium sulfoselenide electrodes

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5763470

Streckert, H H

An introduction to photoelectrochemical cells (PECs) is presented. A brief description of semiconductors is included and a model to explain semiconductor-electrolyte interfacial energetics is developed. Some practical considerations with regard to solar energy conversion are examined. A general description of various characterization techniques is provided. Electroluminescence (EL) of single-crystal, n-type, undoped CdS and Te-doped CdS electrodes is examined in aqueous, alkaline peroxydisulfate electrolyte. Addition of Te to CdS introduces intraband gap states which drastically alter the EL spectral distribution. PL spectra, obtained with 457.9-nm excitation, are generally similar to their EL counterparts and aid in the assignments of the emissive transitions. The potential dependence of the EL spectra was examined between approx.-1.2 and -2.0 V vs. SCE. Lower-limit estimates of EL efficiency under steady-state conditions have been made. Polarization properties of CdSe emission are also reported. Inhomogeneous samples of n-type CdS/sub x/Se/sub 1-x/ containing a graded region were prepared by vapor-phase diffusion of S into a CdSe substrate. Regions from which PL and EL originate can be inferred from their spectral distribution in combination with Auger/depth-profile data. When the sample is used as the photoanode in a PEC, nonuniform quenching of the PL spectrum is observed during the passage of photocurrent. With certain assumptions, the PL quenching properties provide a map relating the efficiency of electron-hole pair separation to distance from the semiconductor-electrolyte interface.

• OSTI ID: 5763470
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
ANODES
CADMIUM COMPOUNDS
CADMIUM SELENIDES
CHALCOGENIDES
CHARGE TRANSPORT
DEACTIVATION
DOPED MATERIALS
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROLYTES
EQUIPMENT
MATERIALS
PHOTOANODES
PHOTOELECTROCHEMICAL CELLS
POLARIZATION
SELENIDES
SELENIUM COMPOUNDS
SOLAR EQUIPMENT