Emissive gold(iii) complexes with liquid-crystalline properties have been prepared, with most complexes showing a columnar hexagonal phase. The emissive response has been characterised in solution and in OLED devices.

It is crucial to maintain both an ordered intermolecular packing and deep highest occupied molecule orbital energy levels (E HOMO ) for cutting-edge organic solar cells (OSCs) with a high open-circuit voltage (V OC ). Although halogen substitution has become the most popular strategy to lower the E HOMO of donor materials, there still remains great room for exploring new approaches to construct wide-band gap small-molecule donors (SMDs) with a deeper E HOMO . For this purpose, in this work, we primarily took a strategy of diester-terthiophene as a π-bridged unit to construct a type of wide-band gap SMDs named BER6 and BECN with an A−π−D−π−A framework using alkyl-thienyl-substituted benzo-dithiophene as a central electron-donating (D) unit and rhodanine or cyanoacetate derivatives as a terminal electron-accepting (A) unit. It is found that both molecules have almost coincident coplanarity and dipole interaction for the diesterterthiophene unit. As a result, an ordered molecular stacking and a deep E HOMO of about −5.40 eV with an optical band gap of 1.85−1.91 eV are presented for both molecules. A high power conversion efficiency of 9.03% with a high V OC of 0.97 eV was obtained in the BER6/IDIC-based all-smallmolecule OSCs (ASM-OSCs). Our results demonstrate that diester-terthiophene is a promising strategy to develop wide-band gap SMDs applied in high-performance ASM-OSCs.

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The fluorine-free simple-structure acceptor presents matched energy levels and higher charge mobilities, thus enhanced photovoltaic properties.