A novel series of conjugated copolymers having oxadiazole, quinoline, quinoxaline, and phenylenecyanovinylene moieties in the main chain based on fluorene were synthesized in good yields by palladium-catalyzed Suzuki coupling reaction, a new approach different from the traditional polyhydrazide precursor route (oxadiazole-containing polymers), acid-catalyzed Friedla ¨nder condensation reaction (polyquinolines), and Knoevenagel condensation polymerization (poly(phenylenecyanovinylene)). The thermal, electrochemical, and optical properties of these copolymers were examined. All these polymers possess excellent thermal stability with glass transition temperatures of 114-208 °C and onset decomposition temperatures of 387-415 °C. Cyclic voltammetry studies reveal that these copolymers possess low-lying LUMO energy levels ranging from -3.01 to -3.37 eV and low-lying HOMO energy levels ranging from -6.13 to -6.38 eV and may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes. The polymers in thin films emit strong blue luminance around 414-476 nm with narrow bandwidth upon photoexcitation. Photoluminescence spectra of the polymers in the films are only red-shifted by 7-11 nm compared to those in the solution, indicating that the aggregation and the excimer fluorescence are suppressed.

Significant progress has been made in nonfullerene small molecule acceptors (NF‐SMAs) that leads to a consistent increase of power conversion efficiency (PCE) of nonfullerene organic solar cells (NF‐OSCs). To achieve better compatibility with high‐performance NF‐SMAs, the direction of molecular design for donor polymers is toward wide bandgap (WBG), tailored properties, and preferentially ecofriendly processability for device fabrication. Here, a weak acceptor unit, methyl 2,5‐dibromo‐4‐fluorothiophene‐3‐carboxylate (FE‐T), is synthesized and copolymerized with benzo[1,2‐b:4,5‐b′]dithiophene (BDT) to afford a series of nonhalogenated solvent processable WBG polymers P1‐P3 with a distinct side chain on FE‐T. The incorporation of FE‐T leads to polymers with a deep highest occupied molecular orbital (HOMO) level of −5.60−5.70 eV, a complementary absorption to NF‐SMAs, and a planar molecular conformation. When combined with the narrow bandgap acceptor ITIC‐Th, the solar cell based on P1 with the shortest methyl chain on FE‐T achieves a PCE of 11.39% with a large V oc of 1.01 V and a J sc of 17.89 mA cm−2. Moreover, a PCE of 12.11% is attained for ternary cells based on WBG P1, narrow bandgap PTB7‐Th, and acceptor IEICO‐4F. These results demonstrate that the new FE‐T is a highly promising acceptor unit to construct WBG polymers for efficient NF‐OSCs.

Soluble rare-earth complexes LiEu(TTA) 4 , NaEu(TTA) 4 , and KEu(TTA) 4 [TTA ) 2-thenoyltrifluoroacetonato] were synthesized, and their luminescence properties doped in poly(Nvinylcarbazole) (PVK) thin films and in different solvents were observed. The results indicate that the emission comes from the Eu 3+ ion. The photoluminescence spectra of NaEu(TTA) 4 are independent of the solvent, with the exception of the luminescence intensity. When NaEu-(TTA) 4 is doped into PVK films, the luminescence intensity of the Eu 3+ ion is enhanced with increasing NaEu(TTA) 4 concentration in the PVK film. The nature of the cations in the Eu 3+ complexes does not affect the luminescence performance and processability of the complexes. Single-, double-, and three-layer light-emitting diodes based on PVK doped with LiEu(TTA) 4 , NaEu(TTA) 4 , and KEu(TTA) 4 as an active layer were fabricated and investigated.

The precise control of monomer sequence and stereochemistry in copolymerization is of much interest and importance for the synthesis of functional polymers, but studies toward this goal have met with only limited success to date. Now, the co‐syndiospecific alternating copolymerization of methoxyphenyl‐ and N,N‐dimethylaminophenyl‐functionalized propylenes with styrene by half‐sandwich rare‐earth catalysts is reported. This reaction efficiently afforded the corresponding functionalized propylene‐alt‐styrene copolymers with a perfect alternating sequence and excellent co‐syndiotacticity (rrrr >99 %), thus constituting the first example of co‐stereospecific alternating copolymerization of polar and non‐polar olefins.