Research Article Open Access

Reducing the Bandgap Energy via Doping Process in Lead-Free Thin Film Nanocomposites

Abstract

There are numerous applications for the pyroelectric composite films in the medical field, military field and environmental applications field. The main focus of this research is to fabricate the higher efficiency thin films that are flexible like the polymers. PVDF is ideal when it comes to making detectors as they are flexible; possess high pyroelectric current and resistance, low dielectric constant and density. Pure PVDF and PVDF films doped with CNT and MWCNT, PVDF: LiTaO3, PVDF: LiTaO3 films doped with MWCNT thin films were fabricated using the solution casting technique. Films fabricated were characterized for their electrical, optical and structural properties using FTIR Spectroscopy, UV-Vis Spectroscopy, and Raman Spectrum. From UV-Vis spectroscopy analysis it is calculated that the indirect bandgap energy of pure PVDF is 5.99 eV, 4.85 eV for PVDF+0.5%-CNT, 4.76 eV for PVDF+1%-CNT, 5.22 eV for PVDF+LT, 4.95 eV for PVDF+LT+2%-MWCNT and 4.85 eV PVDF+LT+2.5%-MWCNT. The calculated direct bandgap energy of pure PVDF is 6.25 eV, 5.95 eV for PVDF+0.5%-CNT, 4.85 eV for PVDF+1%- CNT, 5.42 eV for PVDF+LT, 5.12 eV for PVDF+LT+2%-MWCNT and 4.95 eV PVDF+LT+2.5%-MWCNT. The decrease in the bandgap may be attributed to the presence of unstructured bulk defects. Obtained results show that doping of PVDF and its nanocomposite materials with CNT and MWCNT is enhancing the key characteristics of the materials that are beneficial for the optical devices industry.

Guggilla P, Chilvery A and Powell R

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