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Two new oligothiophene derivatives with the acceptor–donor–acceptor structure incorporating fluorinated alkyl cyanoacetate units as the terminal acceptor groups, DCAE7T-F1 and DCAO7T-F7, have been designed and synthesized for solution-processable BHJ solar cells. The impacts of these fluorinated end groups on the optical absorption, solubility, electrochemical properties, morphology, surface energy, film forming ability, mobility and solar cell performance were studied. We found that as the fluorinated alkyl length increased, the surface energy decreased and the lipophobicity increased. Due to its high lipophobic property and a problem with its wettability, DCAO7T-F7 was not able to produce a uniform film by spin coating. A power conversion efficiency (PCE) of 2.26% was achieved with an open-circuit voltage (Voc) of 0.83 V, short circuit current (Jsc) of 5.55 mA cm−2 and fill factor (FF) of 0.50 for DCAE7T-F1 based solar cells. The low Jsc suggests that controlling the film morphology and molecular assembly is essential for the performance of these fluorinated small molecules. [ABSTRACT FROM AUTHOR]

Two similar dithiafulvalene-fused conjugated polymers, with different donor–acceptor (D–A) structures, were synthesised. The polymers have different band gaps and stacking structures, as proven by the experimental results and computational studies. [ABSTRACT FROM AUTHOR]

A simplified triple-layered pure red organic light-emitting diode with high efficiency and a slow efficiency roll-off was fabricated by using Eu(DBM)3(sbf) (DBM = dibenzoylmethane, sbf = 4,5-diaza-9,9′-spirobifluorene) as emitter. In particular, an impressive current efficiency of 3.31 cd A−1and an external quantum efficiency of 1.8% were maintained at a high luminance of 100 cd m−2. [ABSTRACT FROM AUTHOR]

With N-(5-phenyl-1,3,4-oxadiazol-2-yl)-benzamide (HL1) as the first ligand, three new luminescent europium complexes Eu2Na2(L1)6(OH)(2).2C2H5OH.2CHCl3 (1), Eu(L1)3(phen) (phen = 1,10-phenanthroline) (2) and Eu2Na2(L1)6(L2)2(OH)(2).8CHCl3 [L2 = 2,5-bis(2-pyridyl)-1,3,4-oxadiazole] (3) have been prepared and structurally characterized. Each ligand L1 coordinates with a Eu3+ ion through a carbonyl oxygen atom and oxadiazol nitrogen atom, the coordination geometry at europium is a distorted square antiprism. Complexes 1 and 3 have centrosymmetric dimeric structural features with OH- as the bridging ligand, while 2 is mononuclear with phen as the neutral ligand. All these complexes show efficient red emissions typical of Eu3+ ions at room temperature, the overall quantum yields of complexes 1, 2 and 3 were 0.15, 0.37 and 0.23, respectively. Using Eu(L1)3(phen) as the emitting material, an electroluminescent device with the structure ITO/TPD (30 nm)/Eu(L1)3(phen): TPD (1 : 3, 50 nm)/AlQ (30 nm)/Mg(0.9)Ag(0.1)/Ag was fabricated. The device emits sharp red light originating from europium complex, demonstrating that Eu(L1)3(phen) is a promising red emitter with good electron-transporting property.