Characterizations of structural and optical properties of 2-(pyranoquinolin-4-yl) malononitrile

Thin films of 2-(pyranoquinolin-4-yl) malononitrile, PQM, are deposited by thermal evaporation technique. X-ray diffraction pattern of the powder and thin films with different thicknesses are investigated. Crystallite size, strain and dislocation are determined. Optical properties of PQM thin films are studied in wavelength range of 200-2500 nm using spectrophotometric measurements of transmittance and reflectance. The optical constants are calculated. Direct and indirect optical energy gaps of PQM thin films are estimated. Dispersion parameters as oscillator energy and dispersion energy are determined using single-oscillator model. The real and imaginary parts of dielectric constant show maxima at 1.24, 1.49, 2.75, 3.54 eV.