Flash Photolysis Time Resolved Microwave

A. Saeki, S. Seki, T. Sunagawa, K. Ushida, S. Tagawa, Charge-carrier dynamics in polythiophene films studied by in situ measurement of flash-photolysis time-resolved microwave conductivity (FP-TRMC) and transient optical spectroscopy (TOS). Philos. Mag. 86, 1261-1276 (2006)... 

Osuka, Anderson, and Warman have investigated the polarizability of two different covalently bridged porphyrin oligomers by flash photolysis time-resolved microwave conductivity measurements. When the bridge forbids electronic interactions, only electrostatic interactions are present and the excitation generates Frenkel-type excitons. Upon photoexcitation, only a slight increase of polarizability is observed (<20 A ). When electronic communication is permitted by... 

BET = Brunauer-Emmett-Teller CMON = covalent metal-organic networks CTF = covalent triazine-based framework DCQNI = A,A -dicyanoquinodiimine DEF = A,A-diethylformamide DMA = A,A-dimethyl-acetamide FP-TRMC = flash-photolysis time-resolved microwave conductivity HHT = 2,3,6,7,10,11-hexa-hydroxytriphenylene M-CAT = metal-catecholate PSM = postsynthesis modifications PXRD = powder X-ray diffraction TCNQ = tetracyanoquinodimethane TOF = time-of-flight TTF = tetrathiafulvalene. 

Besides doping, the hetero-junction formed by semiconductors of different nature can enhance charge transfer. Savenije and his coworkers using the flash-photolysis time-resolved microwave conductivity technique (FP-TRMC) studied... 

The electrical conductivity of the i-stacked polymer was investigated by the flash-photolysis time-resolved microwave conductivity (FP-TRMC) method [57-68]. We could observe the charge mobility in 22e through the stacked r-electron systems in a single polymer chain using this noncontact measurement technique [30], Polymer 22e was dispersed in a polystyrene film without any dopants, and the cast film on quartz was excited by a laser pulse at 355 nm. The kinetic traces of microwave... 

A laser pulse can be used instead of the van der Graff generator to produce the electron-hole pair, which is a technique known as flash photolysis, time-resolved, microwave conductivity or FP-TRMC. The main disadvantage is that the concentration of electron-hole pairs formed in this way is more difficult to estimate. Usually, it can only be used to measure the product of the quantum yield and the sum of the mobilities (oriented films [15,16]. More recently a variation on this method has been introduced in which the transient absorption spectrum is measured simultaneously. This provides structural information on the charge carriers and (provided assumptions are made) allows their concentration to be determined yielding Sp, [17,18]. 

A separate development of the TRMC techniques was their application to the study of dipolar and excitonic species formed on flash-photolysis of dilute solutions and, more recently, to charge transport and charge separation in thin (aligned) solid films. In the present review we restrict ourselves to results that we have obtained on pulse-irradiated materials, for which the method has become known as the pulse-radiolysis time-resolved microwave conductivity or PR-TBAIC technique. 

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