1,3-Bis(thieno[3,4-b]thiophen-6-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione-Based Small-Molecule Donor for Efficient Solution-Processed Solar Cells

Zhongbo Zhang; Zichun Zhou; Qin Hu; Feng Liu; Thomas P Russell; Xiaozhang Zhu

doi:10.1021/acsami.6b14572

1,3-Bis(thieno[3,4-b]thiophen-6-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione-Based Small-Molecule Donor for Efficient Solution-Processed Solar Cells

ACS Appl Mater Interfaces. 2017 Feb 22;9(7):6213-6219. doi: 10.1021/acsami.6b14572. Epub 2017 Feb 8.

Authors

Zhongbo Zhang^{1

2}, Zichun Zhou^{1

2}, Qin Hu³, Feng Liu⁴, Thomas P Russell³, Xiaozhang Zhu^{1

2}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.
² School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences , Beijing 100049, China.
³ Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
⁴ Department of Physics and Astronomy, and Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiaotong University , Shanghai 200240, P. R. China.

PMID: 28125200
DOI: 10.1021/acsami.6b14572

Abstract

A small molecule TBTT-1 with 5-(2-ethylhexyl)-1,3-bis(2-(2-ethylhexyl)thieno[3,4-b]thiophen-6-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TBTT) as the central moiety was designed and synthesized for solution-processed bulk-heterojunction solar cells. TBTT-1 exhibits a broad absorption with a low optical band gap of approximately 1.53 eV in the thin film. An optimized power conversion efficiency (PCE) of 7.47% with a high short-circuit current of 14.95 mA cm^-2 was achieved with diphenyl ether (DPE) as additive, which is the highest PCE for TPD-based small-molecule solar cells. According to the detailed morphology investigations, we found that DPE processing helped to enhance π-π stacking and reduce the scales of phase separation, which led to improved exciton splitting and charge transport in BHJ thin film, and thus enhanced device performance.

Keywords: donor material; power conversion efficiency; small-molecule solar cell; thieno[3,4-b]thiophene; thieno[3,4-c]pyrrole-4,6(5H)-dione.