Photovoltaic properties of the 4H-pyrano[3,2-c]quinoline derivatives and their applications in organic–inorganic photodiode fabrication

2-Amino-6-ethyl-5-oxo-4-(3-Ph)-5, 6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitrile (Ph-HPQ) and
2-Amino-4-(2-Cl)-6-ethyl-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitrile (Ch-HPQ)
films
are deposited by using thermal evaporation technique. The absorbance of quinoline derivatives and the
energy band diagrams of Ph-HPQ/p-Si and Ch-HPQ/p-Si devices are illustrated. The electrical properties
of Au/Ph-HPQ/p-Si/Al and Au/Ch-HPQ/p-Si/Al heterojunction diodes are studied in terms of current–
voltage characteristics. The two devices are fabricated with the same specifications. They showed a
rectification behavior and photovoltaic properties in dark and under illumination conditions. The
conduction mechanisms and diode parameters as a function of temperature of these devices are
determined. The Schottky barrier height and the
field lowering coefficients are also determined as a
function of temperature. The photoconductivity sensitivity, short circuit current, open circuit voltage and
the ratio between photocurrent to dark current are found to be a function of illumination intensity. The
two devices satisfy the conditions to be used as photodiodes. The presence of the chlorophenyl as a
substitution group improved the diode parameters.