Electric field quenching of recombination fluorescence in photoionized non polar solutions-III. Poole-Frenkel analysis of charge carrier generation

In this paper we use the one dimensional Poole-Frenkel model (PFM) for analyzing photocurrent and electric field fluorescence quenching data obtained with photoionized dilute solutions of TMPD (TMPD= N,N,N′,N′ tetramethylparaphenylenediamine) in non polar liquids. The fluorescence data permit to introduce a sensitive test of PFM applicability called the R-test. In a liquid for which R=1, the behavior of the electron cation pair may be described by the PFM. Several liquids are studied: tetramethylsilane, 2,2-dimethylbutane, 2,2,4-trimethylpentane, cyclopentane and n-hexane. The R-test is better obeyed in tetramethylsilane. It is then suggested that the PFM is a good approximation in liquids in which the electron is quasi-free.