Electrical and Optical Nonlinearity in Vacuum-Deposited Thin Films of Poly[n-(4-Benzoylphenyl)-2-Methylacrylamide]

Abstract

A new optically nonlinear material, poly[N-(4-benzoylphenyl)-2-methylacrylamide], for conversion of wavelength 1064 nm to 532 nm has been synthesized. The material possesses strong electrical and optical nonlinearity required for second harmonic generation (SHG). The thin films of poly[N-(4-benzoylphenyl)-2-methylacrylamide] were prepared by the vacuum-deposition technique. The optical UV-visible, IR, NMR studies, mass spectrometry, surface topography and nonlinear optical properties of the thin films were studied. The vacuum-deposited thin films of the polymer were subjected to optimized high potential multi-point corona poling at temperatures just below the glass transition temperature (Tg ) to create directional orientation of the side chain groups. The optical UV-visible absorption indicates a complete transparency in the visible and IR regions with an absorption peak at ∼ 350 nm. The energy band gap of the polymer was estimated to be ∼ 2.9 eV, from the optical absorption spectra of the thin films. The electrical current-voltage (IV) and optical nonlinear characteristic indicate the strong potential of these polymeric thin films for nonlinear optical (NLO) applications.