Year: 1983
Type: article
Abstract: As shown in the extensive study by Harris and Wilson (i), TiO2 photoanodes tend to undergo aging effects characterized by changes in the action spectra, quantum efficiency, and surface capacitance.Specifics of the aging effect, as well as photoelectrochemical behavior in general, depend on the method of anode Preparation (2-4) 9 Migration of interstitial Ti +a (5) and hydrogen ions (2, 4) has been proposed as contributing to the effect although the detailed mechanisms remain obscure.The situation with hydrogen-loaded specimens is complicated by the observations that hydrogen in both TiO2 single crystals (6) and sputtered films (7) appears to occupy different sites not all of which are electrochemically active.Reported here are some striking aging effects observed with relatively highly doped TiO~ anodes which have been exposed in the dark to alkaline solutions for somewhat over 100 hr.No detailed explanation for the effects noted is available at this time.Single crystals of TiO2 (National Lead Corporation) oriented in the (110) plane were employed.These were polished with 0.3/~ A120~ abrasive and then converted to n-type material by heating to 700~ in hydrogen for 20 rain.While a number of specimens were so prepared, we report on a sample with a carrier concentration of 4.8 • 1019/cm 3 as determined by the Mott-Schottky method.The reliability of the carrier concentration was checked with resistivity measurements using the Van derPauw technique (8).These gave a calculated mobility of 1.87 cm2/V-sec at room temperature, in agreement ws the value reported in the literature (9).Indium solder and silver-plated copper wires provided ohmic contacts to the samples.The contacts were protected by a coating of silicone rubber and a glass tube.The cell was fabricated of Pyrex and provided with a quartz window to admit illumination.A platinu m counterelectrode and a saturated calomel reference electrode (SCE) were employed 9 The electrolyte used was 0 9 NaOH.9 Electrochemical Society,Active Member.
DOI: 10.1149/1.2119852
Authors: Fu‐Tai Liou, Chiang Y. Yang, Sumner N. Levine
Institutions: Brookhaven National Laboratory, Stony Brook University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: bronze
Funder: U.S. Department of Energy
Awards: G433534989, G666034064, G7212048212, G969889393
OpenAlex ID: W1830626554