Effects of Organic Solvents for Composite Active Layer of PCDTBT/PC71BM on Characteristics of Organic Solar Cell Devices

Paik-Kyun Shin,Shizuyasu Ochiai,Palanisamy Kumar,Abhirami Kumar,Santhakumar Kannappan

doi:10.1155/2014/786468

Paik-Kyun Shin, Shizuyasu Ochiai + Show 3 more

Open Access

https://doi.org/10.1155/2014/786468

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Abstract

Bulk heterojunction (BHJ) structure based active layers of PCDTBT/PC71BM were prepared by using different organic solvents for fabrication of organic solar cell (OSC) devices. Mixture of precursor solutions of PCDTBT/PC71BM in three different organic solvents was prepared to fabricate composite active layers by spin-coating process: chloroform; chlorobenzene; o-dichlorobenzene. Four different blend ratios (1 : 3–1 : 6) of PCDTBT: PC71BM were adopted for each organic solvent to clarify the effect on the resulting OSC device characteristics. Surface morphology of the active layers was distinctively affected by the blend ratio of PCDTBT/PC71BM in organic solvents. Influence of the blend ratio of PCDTBT/PC71BM on the OSC device parameters was discussed. Performance parameters of the resulting OSC devices with different composite active layers were comparatively investigated. Appropriate blend ratio and organic solvent to achieve better OSC device performance were proposed. Furthermore, from the UV-Vis spectrum of each active layer prepared using the PCDTBT/PC71BM mixed solution dissolved with different organic solvents, a possibility that the nanophase separation structure inside their active layer could appear was suggested.

Highlights

The 2007 Nobel Prize for peace was awarded to Al Gore and intergovernmental panel on climate change (IPCC)
The thickness of the PCDTBT : phenyl-C71-butyric acid methyl ester (PC71BM) layer gradually decreases while increasing the PC71BM acceptor in the case of chlorobenzene and o-dichlorobenzene, whereas it is random for chloroform
The blended active layers of PCDTBT : PC71BM were prepared by spin-coating technique, with different blend ratios of 1 : 3 to 1 : 6 being adopted for three different organic solvents of chloroform (1 wt%), chlorobenzene (2 wt%), and o-dichlorobenzene (3 wt%), respectively

Summary

Introduction

The 2007 Nobel Prize for peace was awarded to Al Gore and intergovernmental panel on climate change (IPCC). Wang et al reported a PCE of 7.1% for devices prepared by spin-coating 1,2-dichlorobenzene : chlorobenzene solution of PCDTBT : PC70BM (3 : 1) with silver nanoparticles used in the active layer [24]. The precursor mixture solutions were used for spin-coating process to fabricate BHJ structure based OSC devices. To clarify the influence of the organic solvent on the characteristic and/or the OSC device performance, three different organic solvents were utilized to prepare precursor solution mixtures for blended active layer preparation: (1) chloroform of 1 wt%; (2) chlorobenzene of 2 wt%; (3) o-dichlorobenzene of 3 wt%. The prepared precursor solutions of PCDTBT : PC71BM mixture were used in a spin-coating process to prepare bulk heterojunction structure active layer of the organic solar cell devices: rotation speed of 1000 rpm and rotation time of 60 s.

Experimental Procedure

Characterization of Organic Active Layers and Organic

Results and Discussion

Summary and Conclusions