摘要:

AbstractThree examples are presented demonstrating the wealth of information steady state absorption and fluorescence studies can yield regarding charge transport in polymeric systems: (i) The determination of the density of intrinsic and extrinsic hopping states in polyvinylcarbazole via site‐selective fluorescence spectroscopy by drawing on the analogy between charge and energy localization in disordered organic media, (ii) the identification of inter‐chain jumps as being rate limiting for charge transport in a polydiacetylene single crystal as an example for conjugated polymers and (iii) the elucidation of polaron formation in phenylenevinylene‐type pol

ISSN:0258-0322    

DOI:10.1002/masy.19900370103

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractTransient absorption, fluorescence and conductivity were measured on phenylated poly(phenylenevinylene)s (P‐PPV) in solution and in film after UV pulse excitation in picosecond region. Transient absorption bands of distinguishable rise and decay kinetics were observed. The fluorescence shows two exponential decay times in ps‐ and ns‐region, resp, Transient photoconductivity also exhibits a ps‐ and a ns‐time component. The mobility of carriers was

ISSN:0258-0322    

DOI:10.1002/masy.19900370104

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractMeasurements were carried out of the change of polarity of photo‐current after a laser flash on poly(N‐vinylcarbazole) with trinitrofluorenone (PVK/TNF). This experimental results could be interpreted by taking into consideration dipol‐relaxations. A model for estimation is pres

ISSN:0258-0322    

DOI:10.1002/masy.19900370105

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe role played by the law of the conservation of momentum in the primary processes of charge carrier generation is considered. External magnetic field is shown to be able to influence the rate constants governing spin dependent processes. Magnetic field effect and Reaction Yield Detected Magnetic Resonance on the photoconductivity of organic solids give important information on the mechanism of primary steps of charge photogeneration.

ISSN:0258-0322    

DOI:10.1002/masy.19900370106

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe dependence of the quantum yield of free charge carriers on the electric field strength in quasi‐one‐dimensional photosemiconductors is rationalized. The occurrence of the trapping and nongeminate recombination in the bulk of the material is shown to be responsible of nonzero yield at zero external field. Currentivs. excitation intensitygplot obeys the lawi∼g2/3for polydiacetylene single crystal as expected from theory pres

ISSN:0258-0322    

DOI:10.1002/masy.19900370107

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractIt is demonstrated that spin dynamics study is useful for what kinds of systems, on what theoretical basis of analysis, with what kinds of techniques and to get what kinds of information, showing a nice example of polyacetylene. Usefulness of electron spin resonance (ESR) study is stressed especially in a wide frequency range from 5 to 24000 MHz.

ISSN:0258-0322    

DOI:10.1002/masy.19900370108

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA considerable amount of information about optical and electronic properties of polyacetylenes has been obtained during the last decade from vibrational spectroscopy. In this lecture several basic points not yet fully understood will be discussed and a new method for evaluating the vibrational density of states for random defects will be presented.

ISSN:0258-0322    

DOI:10.1002/masy.19900370109

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper gives a review on the use of resonance Raman spectroscopy to analyse electronic and molecular structures of π‐conjugated and σ‐conjugated polymers. It starts with a short introduction into the present state of research in the field of conducting polymers and with a very short introduction into the principles of resonance Raman spectroscopy. Then the potentialities of the technique are demonstrated for the examples of the analysis of conjugation length in polyacetylene, for studying the thermochromic phase transition in polysilanes and in polyalkylthiophenes, for a sudy of the doping processes in polyaniline and finally for an analysis of the ground state in the narrow gap system polyisothianaphthene. Advantages and pitfalls for such analyses are out

ISSN:0258-0322    

DOI:10.1002/masy.19900370110

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractResults of conductivity measurements on undoped and iodine or bromine doped poly(tetrathiafulvalenes) are reported. At higher temperatures the temperature dependence of the d.c. conductivity can be best described by σd.c.= °o. exp(T/To)1/4, typical for variable range hopping. The a.c. conductivity follows the general law °(ω) ∼ ω2for frequencies higher than a critical frequency. A description of the frequency dependent conductivity is given by the extended pair approximation (EPA). At lower temperatures a deviation from linearity of the function in σ versus T−1/4is

ISSN:0258-0322    

DOI:10.1002/masy.19900370111

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe frequency and temperature dependence of the complex conductivity σ* is measured for several different conducting polymeric systems: (i) for poly(p‐styrene sulfonate) salts of polypyrrole, (ii) for salts of poly(cycloalkyl[c]pyrroles) and for ion conducting polymers such as ionenes. The results are discussed in terms of a modified Debye‐Hückel‐Falkenhagen

ISSN:0258-0322    

DOI:10.1002/masy.19900370112

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY