Morphological, structural, optical, and photovoltaic cell of copolymer P3HT: ICBA and P3HT:PCBM

Abstract

Thin films of P3HT (3-hexylthiophene-2,5-diyl):PCBM(phenyl-C61-Butyric-Acid-Methyl Ester) and P3HT:PCBM and P3HT:ICBA (indene-C60 bisadduct) blends with different volume ratios (1:1, 1:2 and 1:3) were successfully prepared using a spin coating technique. Atomic force microscopy (AFM) along with X-ray diffraction (XRD) were utilized to examine the morphological and the crystal structural characterization of the prepared thin films. The capacitance–voltage (C-V) and conductance-voltage (G-V) characteristics were evaluated at a fixed frequency with rang of applied voltage from (−2 up to 2 V). The Mott-Schottky analysis was applied to C-V measurements of P3HT: PCBM, ICBA bulk heterojunction solar cells. The doping densities and built-in voltages were determined as significant implications to understand the physics of these devices. The potential difference between the Fermi level and the bottom of the HOMO level in the p-type organic semiconductor as well as the barrier height were determined. The capacitance-frequency (C-F) and conductance-frequency (G-F) were measured in the range of 0 Hz to 100 MHz at room temperature and then, the number of the interface states due to the depletion was determined.