Electrical conductivity of chlorophyll with polythiophene thin film as solar cell

Abstract

Polythiophene (PT) and Chlorophyll (CHLO) were organic materials. Polythiophene was the conducting polymer that can exhibit electronic properties such as organic solar cell which approach to those of some semiconductors. Chlorophyll was organic materials which can react as photo receptor. In this work, materials were deposited in bulk hetero-junction. Spin coating method was a technique that used to deposite the combination of PT and CHLO thin film on the Aurum (Au) layer where Au thin film would be prepared with three different ratio of 1:1, 1:5, 1:10 and reversed. The optical characterization of thin film was measured using UV-Visible Spectrophotometer to study the optical absorption and to calculate the energy gap of CHLO and PT and the combinations of them. Four Point Probe, Pyronometer Sensor with Data Logger were used to determine the film electrical properties. The electrical conductivity of the thin film with different ratio was measured in the dark and under the light. From the optical absorption study, the maximum wavelength of CHLO:PT thin film one peak. The value of energy gap of CHLO was 5 .12 e V whereas PT was 3. 78 e V. The energy band gap for the CHLO:PT thin film in ratio 1:1, 1:5, 1:10, 5:1 and 10:1 was 4.18 eV, 4.08 eV, 3.91 eV, 4.49 eV and 4.54 eV respectively. The conductivity of CHLO:PT/Au in the dark were in the ranges of0.277 sm· 1 1 • While the and 1.389 sm· conductivity of CHLO:PT/Au in different intensities of light were in the ranges of 0 .154 sm · 1 and 2 .218 sm · 1. Therefore, 1 : 1 thin film was chosen because of the electrical conductivity exceeded the optimum rate value.