Influence of Thickness and Annealing Temperature on the Optical Properties of Spin-Coated Photoactive P3HT:PCBM Blend

Md. Shahinul Islam, Md. Earul Islam, Abu Bakar Md. Ismail, Hartmut Baerwolff

Department of Analog & Optoelectronics, Cologne University of Applied Sciences, Cologne, Germany.
Department of Applied Physics & Electronic Engineering, Rajshahi University, Rajshahi, Bangladesh.
Department of Material Science & Engineering, Rajshahi University, Rajshahi, Bangladesh.

DOI: 10.4236/opj.2013.38A004                

Abstract

Influence of annealing temperature and thickness on the optical characteristics of the blend of poly (3-hexylthiophene) (P3HT) and Phenyl C61 butyric acid methylester (PCBM) layer has been investigated in this report. Photoactive polymer material (P3HT:PCBM) was deposited on indium tin oxide (ITO) substrate by spin-coating. The morphology of P3HT:PCBM composite layer was investigated by Atomic Force Microscope (AFM). The surface roughness was found to reduce after heat treatment. The absorption of the composite layer was found to increase with its number of layer (thickness). On the other hand, the photoluminescence (PL) quenching, which indicates efficient charge separation in the bulk heterojunction, was found higher for the thinner layer. Absorption was also found to increase with the annealing temperature. Therefore, to optimize the thickness of the P3HT:PCBM photoactive layer that will provide best absorption while providing efficient charge separation, annealing at optimized temperature might be an effective tool.

Keywords

Organic Semiconductor; Photoactive Polymer; Bulk Heterojunction; Solar Energy Materials

Conflicts of Interest

The authors declare no conflicts of interest.

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