Comparable structural and optical properties of 4H-pyrano [3, 2-c] quinoline derivatives thin films

ABSTRACT
The structural and optical properties of 2-Amino-6-ethyl-5-oxo-4-
(3-phenoxyphenyl) - 5, 6- dihydro - 4H-pyrano [3,2-c] quinoline-3-
carbonitrile (Ph-HPQ) and 2-Amino-4-(2-chlorophenyl)-6-ethyl-5-
oxo-5,6-dihydro-4H-pyrano [3,2-c] quinoline-3-carbonitrile (Ch-HPQ)
thin films are studied. The compounds are polycrystalline in assynthesised
powder form; they became nanocrystallites dispersed
in amorphous matrix upon thermal deposition to form thin films.
FTIR spectral measurements showed no change in chemical bonds
of the compounds after being deposited to form thin films. The optical
properties have been determined based on spectrophotometer
measurements of transmittance and reflectance at nearly normal
incidence of light in the spectral range of 200–2500 nm. The absorption
parameters, molar extinction coefficient, oscillator strength and
electric dipole strength, are reported. The type of electron transition
is determined from analysis of absorption coefficient spectra near
the onset and optical absorption edges. The onset and optical energy
gaps for Ph-HPQ and Ch-HPQ thin films are determined. The single
oscillator model is applied to calculate the dispersion parameters of the
investigated thin films. In addition, oscillator and dispersion energies,
the high-frequency dielectric constant, lattice dielectric constant and
ratio of free charge carriers concentrations to their effective masses
are evaluated for the compounds under investigation.