D(A-A′)2 architecture: An efficient strategy to improve photovoltaic performance of small molecules for solution-processed organic solar cells. (October 2016)

• Record Type: Journal Article
• Authors: Tao, Qiang; Duan, Linrui; Xiong, Wenjing; Huang, Gongyue; Wang, Pu; Tan, Hua; Wang, Yafei; Yang, Renqiang; Zhu, Weiguo
• Is Part Of: Dyes and pigments. Volume 133(2016)
• Page Start: 153
• Page End: 160
• Publication Date: 2016-10
• Subjects: Small molecules -- Benzodithiophene -- Diketopyrrolopyrrole -- Thieno[3, 4-c]pyrrole-4, 6-dione -- Photovoltaic performance -- Organic solar cells; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2016.05.033
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Two novel small molecules (SMs) of BDT(TPD-DPP)2 and BDTT(TPD-DPP)2 with a D(A-A′)2 framework were designed and synthesized, in which the electron-rich benzodithiophene (BDT) and thiophenyl-substituted benzodithiophene (BDTT) are used as a central donor (D) core, as well as the electron-deficient diketopyrrolopyrrole (DPP) and thieno [3, 4-c]pyrrole-4, 6-dione (TPD) as dual acceptor (A and A′) units, respectively. Their optical, electrochemical, and photovoltaic properties were investigated together with their counterparts, which bearing an accepter-donor-accepter (A-D-A) architecture. Wider and stronger solar photon responses and decreasing the lowest unoccupied orbital (LUMO) levels are observed in the D(A-A′)2 rather than A-D-A type SMs. The significantly increasing power conversion efficiency of 4.25% with a short-circuit current density of 10.08 mA cm −2 were obtained in the BDTT(TPD-DPP)2 based solar cells. This work demonstrates that using D(A-A′)2 architecture with dual acceptor units is an effective method to improve photovoltaic performance of SMs for solution-processed organic solar cells. Graphical abstract: Two novel small molecules (SMs) of BDT(TPD-DPP)2 and BDTT(TPD-DPP)2 with a D(A-A′)2 framework were obtained on the basis of the A-D-A type SMs. Significantly improved photovoltaic properties with a power conversion efficiency of 4.25% and a short-circuit current density of 10.08 mA cm −2 were obtained in the D(A-A′)2 type SMs. Highlights: Two SMs of BDT(TPD-DPP)2 and BDTT(TPD-DPP)2 with a D(A-A′)2 framework are prepared. Both SMs exhibit wider absorption and deeper LUMO energy levels than A-D-A type SMs. The BDTT(TPD-DPP)2 based device presents a significantly increasing PCE of 4.25%.