Semiconductors electrochemistry

Nazeeruddin, M. K. Graetzel, M. Dyes for Semiconductor Sensitization. In Encyclopedia of Electrochemistry Semiconductor Electrodes and Photoelectrochemistry, Vol. 6 Licht, S., Ed. Wiley-VCH 2002 Darmstadt, pp 407-431. 

Statistical thermodynamics takes into account the microscopic structure of matter and how it is constituted. According to - Boltzmann the entropy can be correlated with the microscopic disorder of the system. Beside the Boltzmann distribution formula (- Debye-Htickel equation) other statistics (e.g., - Fermi-Dirac statistics) are of importance in electrochemistry (- semiconductors, -> BCS theory). 

The combination of electrochemistry and photochemistry is a fonn of dual-activation process. Evidence for a photochemical effect in addition to an electrochemical one is nonnally seen m the fonn of photocurrent, which is extra current that flows in the presence of light [, 89 and 90]. In photoelectrochemistry, light is absorbed into the electrode (typically a semiconductor) and this can induce changes in the electrode s conduction properties, thus altering its electrochemical activity. Alternatively, the light is absorbed in solution by electroactive molecules or their reduced/oxidized products inducing photochemical reactions or modifications of the electrode reaction. In the latter case electrochemical cells (RDE or chaimel-flow cells) are constmcted to allow irradiation of the electrode area with UV/VIS light to excite species involved in electrochemical processes and thus promote fiirther reactions. 

As outlined above, electron transfer through the passive film can also be cmcial for passivation and thus for the corrosion behaviour of a metal. Therefore, interest has grown in studies of the electronic properties of passive films. Many passive films are of a semiconductive nature [92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102 and 1031 and therefore can be investigated with teclmiques borrowed from semiconductor electrochemistry—most typically photoelectrochemistry and capacitance measurements of the Mott-Schottky type [104]. Generally it is found that many passive films cannot be described as ideal but rather as amorjDhous or highly defective semiconductors which often exlribit doping levels close to degeneracy [105]. 

Sato N 1998 Electrochemistry at Metal and Semiconductor Electrodes (Amsterdam Elsevier)... 

Morrison S R 1980 Electrochemistry at Semiconductor and Oxidized Metal Electrodes (New York Plenum) Dean M FI and Slimming U 1987 J. Electroanal. Chem. 228 135 Boehni FI 1987 Langmuir 3 924... 

For tire purjDoses of tliis review, a nanocrystal is defined as a crystalline solid, witli feature sizes less tlian 50 nm, recovered as a purified powder from a chemical syntliesis and subsequently dissolved as isolated particles in an appropriate solvent. In many ways, tliis definition shares many features witli tliat of colloids , defined broadly as a particle tliat has some linear dimension between 1 and 1000 nm [1] tire study of nanocrystals may be drought of as a new kind of colloid science [2]. Much of die early work on colloidal metal and semiconductor particles stemmed from die photophysics and applications to electrochemistry. (See, for example, die excellent review by Henglein [3].) However, the definition of a colloid does not include any specification of die internal stmcture of die particle. Therein lies die cmcial distinction in nanocrystals, die interior crystalline stmcture is of overwhelming importance. Nanocrystals must tmly be little solids (figure C2.17.1), widi internal stmctures equivalent (or nearly equivalent) to drat of bulk materials. This is a necessary condition if size-dependent studies of nanometre-sized objects are to offer any insight into die behaviour of bulk solids. 

This discussion has shown how useful PMC measurements are for addressing new questions in semiconductor electrochemistry. 

Electrochemistry of Semiconductors New Problems and Prospects Pleskov,Y.V. Gurevich, Y. Y. 16... 

Theoretical Aspects of Semiconductor Electrochemistry Uosaki, K. Kita, H. 18... 

N. Sato, Electrochemistry at metal and semiconductor electrodes, Elsevier, Amsterdam (1998). 

ELECTROCHEMISTRY OF SEMICONDUCTORS AND ELECTRONICS edited by John McHardy and Frank Ludwig... 

Hodes G (1995) Electrodeposition of 11-Vl semiconductors, in Rubinstein I (ed.) Physical Electrochemistry Principles, Methods, and Applications. Marcel Dekker, New York... 

Electrochemistry provides routes to directly prepare nanostructures both delocalized in a random or organized way and localized at predefined surface sites with adjustable aspect ratios. Purity, monodispersity, ligation, and other chemical properties and treatments are definitely important in most cases. By delocalized electrodeposition it is possible to decorate large areas of metal or semiconductor surfaces with structures of a narrow size distribution stable nuclei-clusters can be... 

Hodes G, Rubinstein I (2001) Electrodeposition of semiconductor quantum dot films. In Hodes G (ed) Electrochemistry of Nanostructures, Wiley-VCH, Weinheim... 

Gerischer H (1970) Semiconductor Electrochemistry. In Eyring H (ed) Physical Chemistry - An advanced treatise Vol IXA, Academic Press, New York... 

Frank SN, Bard AJ (1975) Semiconductor Electrodes. 11. Electrochemistry at n-type Ti02 electrodes in acetonitrile solutions. J Am Chem Soc 97 7427-7433... 

Licht S, Khaselev O, Ramakrishnan PA, Soga T, Umeno M (1998) Multiple-bandgap photoelectrochemistry Bipolar semiconductor ohmic regenerative electrochemistry. J Phys Chem B 102 2536-2545... 

Electrogenerated chemiluminescence (ECL) has proved to be useful for analytical applications including organic analysis, ECL-based immunosensors, DNA probe assays, and enzymatic biosensors. In the last few years, the electrochemistry and ECL of compound semiconductor nanocrystallites have attracted much attention due to their potential applications in analytical chemistry (ECL sensors). 

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