A Highly Crystalline Fused‐Ring n‐Type Small Molecule for Non‐Fullerene Acceptor Based Organic Solar Cells and Field‐Effect Transistors

A Highly Crystalline Fused‐Ring n‐Type Small Molecule for Non‐Fullerene Acceptor Based Organic Solar Cells and Field‐Effect Transistors

Xin Song  Nicola Gasparini  Masrur Morshed Nahid  Hu Chen  Sky Marie Macphee  Weimin Zhang Victoria Norman  Chenhui Zhu  Daniel Bryant  Harald Ade  Iain McCulloch  Derya Baran."A Highly Crystalline Fused‐Ring n‐Type Small Molecule for Non‐Fullerene Acceptor Based Organic Solar Cells and Field‐Effect Transistors". Advanced Functional Materials 28 (35), 1802895

Xin Song Nicola Gasparini Masrur Morshed Nahid Hu Chen Sky Marie Macphee Weimin Zhang Victoria Norman Chenhui Zhu Daniel Bryant Harald Ade Iain McCulloch Derya Baran
Fused-ring small molecules, non-fullerene acceptors, organic solar cells, field-effect transistors
2018
N‐type organic small molecules (SMs) are attracting attention in the organic electronics field, due to their easy purification procedures with high yield. However, only a few reports show SMs that perform well in both organic field‐effect transistors (OFETs) and organic solar cells (OSCs). Here, the synthesis and characterization of an n‐type small molecule with an indacenodithieno[3,2‐b]thiophene (IDTT) core unit and linear alkylated side chain (C16) (IDTTIC) are reported. Compared to the state‐of‐the‐art n‐type molecule IDTIC, IDTTIC exhibits smaller optical bandgap and higher absorption coefficient, which is due to the enhanced intramolecular effect. After mixing with the polymer donor PBDB‐T, IDTIC‐based solar cells deliver a power conversion efficiency of only 5.67%. In stark contrast, the OSC performance of IDTTIC improves significantly to 11.2%. It is found that the superior photovoltaic properties of PBDB‐T:IDTTIC blends are mainly due to reduced trap‐assisted recombination and enhanced molecular packing coherence length and higher domain purity when compared to IDTIC. Moreover, a significantly higher electron mobility of 0.50 cm2 V−1 s−1 for IDTTIC in OFET devices than for IDTIC (0.15 cm2 V−1 s−1) is obtained. These superior performances in OSCs and OFETs demonstrate that SMs with extended π‐conjugation of the backbone possess a great potential for application in organic electronic devices.