Yanhui Hou

A highly pure red luminescent europium(III) complex with a Schiff base zinc(II) complex as a neutral ligand

A highly pure red luminescent heterobimetallic complex [EuZnL(tta)2(μ-tfa)] (L = N,N′-bis(salicylidene)-2,3-propanediamine, tta = 2-thenoyltrifluoroacetonate, tfa = trifluoroacetate) was synthesized. The EL device with this complex exhibits an inspiring current efficiency of 3.7 cd A−1 at a brightness of 300 cd m−2 and gives a maximum Eu(III)-based pure red emitting luminance of 1982.5 cd m−2 at 13.8 V.

Impact of fluorinated end groups on the properties of acceptor–donor–acceptor type oligothiophenes for solution-processed photovoltaic cells

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.