Effect of Thickness and Composition Ratio of Poly(3-Hexylthiophene) and [6,6]-Phenyl C60-Butyric Acid Methyl Ester Thin Film on Optical Absorption for Organic Solar Cell Fabrication

Abstract

A Blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C60-butyric acid methyl ester (PCBM), a fullerene derivate based donor-acceptor copolymer, is one of the widely used organic solar cell materials for photon-electron conversion. Thin films were developed, characterized, and optimized for optical absorbance. Absorption spectra were measured using a UV-VIS spectrophotometer. In this work, the effects of composition ratios of P3HT:PC 60 BM and various thicknesses was studied in ambient conditions. The P3HT:PC 61 BM thin film was deposited in two different composition ratio (1:1 and 1:3) and fabricated at seven different thicknesses of 20 nm, 30 nm, 35 nm, 87 nm, 98 nm, 115 nm, and 146 nm corresponding to spin coating speeds of 4000rpm, 3000rpm, 2000rpm, 1500rpm, 1250rpm, 1000rpm, and 750rpm, respectively. P3HT:PC 60 BM thin film composition ratio of 1:1 with thickness of 87nm shows relatively better photon absorption optical parameter than P3HT:PC 60 BM composition ratio of 1:3. P3HT: PC 61 BM solution coated at a spin speed of 1500 rpm shows a better absorption of photon energy. The results showed that the optimum thickness of the thin film is 87 nm at composition ratio of 1:1. Energy band gap values of composition ratio of 1:3 is observed to decreases with increase in spin-speed from 3.9 eV to 3.7 eV. The results can be used as a guideline for improving the design and fabrication of active layer of organic solar cells.

The hydrothermal synthesis of blue-emitting boron-doped CQDs and its application for improving the photovoltaic parameters of organic solar cell

“…As known, the Eg values of P3HT:PCBM film depend on the concentration of P3HT:PCBM film as well as thickness of P3HT:PCBM film. 53,54 Besides, the electrical parameters of OSC are affected by increased Eg values due to the chemical composition of P3HT, good crystallinity, and as a result of the gap states formation. Therefore, it can be stated that there is a correlation between the optical properties and the electrical parameters of OSC.…”