Interfacial charge-transfer rates

This means that the PMC signal will, apart from the generation rate of minority carriers and a proportionality constant, be determined by the interfacial charge transfer rate constant kr and the interfacial charge recombination rate sr... 

The interfacial charge-transfer rate constant can be determined when the PMC signal and the photocurrent are measured simultaneously. When the interfacial charge transfer is, on the other hand, very large and Aps negligible, the PMC value becomes... 

Figure 15. Effect of interfacial rate constants on PMC behavior and on the photocurrent (/0 = 1 cm-2), (a) Fast interfacial charge-transferrate, and (b) low interfacial charge-transfer rate.

Experimental evidence with very different semiconductors has shown that at semiconductor interfaces where limited surface recombination and a modest interfacial charge-transfer rate for charge carriers generate a peak... 

As outlined at the beginning of this chapter, combined photocurrent and microwave conductivity measurements supply the information needed to determine three relevant potential-dependent quantities the surface concentration of excess minority carriers (Aps), the interfacial recombination rate (sr), and the interfacial charge-transfer rate ( r). By inserting the... 

With electrochemically studied semiconductor samples, the evaluation of t [relation (39)] would be more straightforward. AU could be increased in a well-defined way, so that the suppression of surface recombination could be expected. Provided the Debye length of the material is known, the interfacial charge-transfer rate and the surface recombination... 

T.W. Hamann, F. Gstrein, B.S. Brunschwig, N.S. Lewis, Measurement of the driving force dependence of interfacial charge transfer rate constants in response to pH changes at n-ZnO/ H20 interfacies, Chem. Phys. 326 (2006) 15-23. 

Forbes M. D. E. and Lewis N. S. (1990), Real-time measnrements of interfacial charge transfer rates at silicon/liquid junctions , J. Am. Chem. Soc. 112, 3682-3683. 

Pomykal K. E. and Eewis N. S. (1997), Measurement of interfacial charge-transfer rate constants at M-type lnP/CH30H junctions , J. Phys. Chem. B 101, 2476-2482. 

The following simple relation between photocurrent and the interfacial charge-transfer rate can be obtained for larger band bending AE is the energy band bending) ... 

The interfacial charge-transfer rate can therefore be determined to a first approximation via the relation... 

Recent experimental studies have confirmed these theoretical expectations for several exemplary semiconductor/liquid interfaces. Detailed rate measurements on n-Si/CHaOH-viologen +/+ g d u-InP/CHaOH interfaces have validated the dependence of on driving force, as predicted by equation (20), and have indicated that the value of at optimal exoergicity is approximately 10 cm s T Scanning electrochemical microscopy measurements of the kinetics at / -WSe2/H2 0-Ru(NHa) +/ + interfaces have yielded an interfacial charge-transfer rate constant of 5.7 x 10 ernes , and estimates of the nuclear terms for this reaction result in a rate constant at optimal exoergicity of 2 x 10 cm s T... 

Hamann TW, Gstrein F, Brunschwig BS, Lewis NS (2005) Measurement of the dependence of interfacial charge-transfer rate constants on the reorganization energy of redox species at n-Zn0/H20 interfaces. J Am Chem Soc 127 13949-13954... 

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