RAMAN SPECTROSCOPY AND PHOTOLUMINESCENCE CHARACTERIZATION OF THE IODINE DOPED PLASMA-POLYMERIZED BIPHENYL THIN FILM

Year 2018, Volume: 60 Issue: 2, 41 - 50, 01.08.2018

Dogan Mansuroglu

Abstract

The
iodine doped plasma-polymerized biphenyl thin film is investigated in this
study. Iodine atoms lead to increase the charge transfer complexes and change
the electronic equilibrium in the polymer structure due to their high
electronegativity. Therefore, the iodine doped films show significant
improvements in the electrical characteristics as compared to the undoped ones.
The results of Raman spectroscopy verify the presence of the iodined groups in
the structure of deposited thin films. The number density of the iodined groups
increases with increasing the radio frequency input power. The I_D/I_G ratio
changes in a range from 0.40 to 072 for the undoped thin films while it
decreases from 0.74 to 0.58 for the iodine doped thin films which can be due to
the rearrangement in the structure. Photoluminescence spectra show a broad red
emission band at about 630 nm as well as unclear bands placed like small
shoulders at 580 nm and 731 nm. These bands become to seem clearly after the
iodine doping process. The conjugation length of the polymer thin films
increases with iodine doping as well as increasing the power values. All
depositions are produced using a capacitively coupled plasma system with 13.56
MHz radio frequency source. During the doping process, the vaporized iodine
material is directly exposed to the plasma discharge and mixed with the
biphenyl polymer material. All results are characterized in detail.

Keywords

plasma polymerization, iodine doping, Raman spectroscopy, photoluminescence

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