A Solution‐Processable Molecule using Thieno[3,2‐b]thiophene as Building Block for Efficient Organic Solar Cells

Abstract

A solution-processed acceptor-π-donor-π-acceptor (A-π-D-π-A) type small molecule, namely DCATT, has been designed and synthesized for the application as donor material in organic solar cells. The fused aromatic unit thieno[3,2-b]thiophene (TT) flanked with thiophene is applied as π bridge, while 4,8-bisthienyl substituted benzodithiophene (BDT) and 2-ethylhexyl cyanoacetate are chosen as the central building block and end group, respectively. Introduction of fused ring to the small molecule enhances the conjugation length of the main chain, and gives a strong tendency to form π-π stacking with a large overlapping area which favors to high charge carrier transport. Small-molecule organic solar cells based on blends of DCATT and fullerene acceptor exhibit power conversion efficiencies as high as 5.20 % under the illumination of AM 1.5G, 100 mW cm(-2) .

Roll coated large area ITO- and vacuum-free all organic solar cells from diketopyrrolopyrrole based non-fullerene acceptors with molecular geometry effects

“…A slight mismatch is observed versus the values determined by CV, which is suspected to derive from the lack of spatial considerations in the simulation. Wei et al 50 found that, for a small molecule donor using the same method as this study, the LUMO exhibits the largest error, which is similar to these ndings.…”

Molecular Design of Benzodithiophene-Based Organic Photovoltaic Materials

“…In addition to the end-capped groups, the π-bridges also played critical roles in tuning the photovoltaic performance for small molecules. Yang et al synthesized S58 using thieno­[3,2- b ]­thiophene as the π-bridge . The introduction of thieno­[3,2- b ]­thiophene prolonged the conjugation length of the main chain and enhanced the π–π stacking, which facilitated the charge carrier transport.…”

“…Yang et al synthesized S58 using thieno [3,2b]thiophene as the π-bridge. 366 The introduction of thieno [3,2b]thiophene prolonged the conjugation length of the main chain and enhanced the π−π stacking, which facilitated the charge carrier transport. The S58-based SMSC device achieved a PCE of 5.20%.…”

Research progress and application of high efficiency organic solar cells based on benzodithiophene donor materials

“…Among them, the higher PCE presented in BDT-UF based OSC can be attributed to the more ideal conjugated structure formed by introducing alkyl-thiophene side chain with ortho-substituted "F" atom in end-capping group. In addition, based on the mian-chian engineering OCAR-TR-T-TR-BDT-TR-T-TR-OCAR, DCATT (2015) was designed by innovatively introducing TR-TT-TR as π-bridge unit; [371] SM-BDT (2021) was constructed by further extending the π-π conjugated plane. [372] Moreover, D(CATBTzT)BDT (2013) and CNRBDB (2014) were also synthesized by Chen et al [373] and Zhang et al [374] in turn, which were designed by adjusting the ratio of donor and acceptor units in the main-chain engineering.…”