Photoionization of donor-acceptor complex by the internal electric field in blend of poly(vinylidene fluoride) and poly(methyl methacrylate)
Review articleOpen access
1995/01/01 Full-length article DOI: 10.1016/0032-3861(95)93100-Z
AbstractThis paper presents a measurement of the photocurrent of a poled blend of 80 wt% poly(vinylidene fluoride) (PVDF) and 20 wt% poly(methyl methacrylate) (PMMA) containing 5 wt% N-phenylcarbazole (PhCz) and 1 wt% 2,4,7-trinitro-9-fluorenone (TNF) molecules and a discussion of the photoionization of the PhCz-TNF complex by the internal electric field. The high internal electric field, of the order of 106 V cm−1, created by the preferential orientation of polar PVDF β crystallites assists the photoionization of an ion-pair in the polymer matrix, and thus free photocarrier formation by the internal electric field can be expected. The photocurrent illuminated from the positive poled side corresponds to the absorption spectrum of PhCz, while the photocurrent from the negative poled side has maximum current in the absorption edge of PhCz and no photocurrent activity in the strong absorption region of PhCz below 330 nm. No photocurrent was measured for the unpoled sample. These results imply that the internal electric field induced by poling has a significant role in carrier photogeneration. Furthermore, the optical absorbance due to the charge-transfer complex between PhCz and TNF increased non-linearly with increasing poling field.
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