title: 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.
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-2was 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.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.|School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Zhongbo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.|School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Zichun
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Qin
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Department of Physics and Astronomy, and Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiaotong University , Shanghai 200240, P. R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Thomas P
authors.identifier: http://orcid.org/0000-0001-6384-5826
authors.initials: TP
authors.lastname: Russell
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.|School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xiaozhang
authors.identifier: http://orcid.org/0000-0002-6812-0856
authors.initials: X
authors.lastname: Zhu
keywords: donor material; power conversion efficiency; small-molecule solar cell; thieno[3,4-b]thiophene; thieno[3,4-c]pyrrole-4,6(5H)-dione