A hemicurcuminoid boron difluoride complex is used as an emitter in organic light-emitting diodes, showing far red/near-infrared electroluminescence with an external quantum efficiency as high as 2.1%. This dye blended in CBP thin films shows amplified spontaneous emission with a threshold of 22 μJ cm at 750 nm, making this compound attractive for organic semiconductor lasers operating in the near-infrared region.

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International audienceWe report on the near infrared electroluminescence properties of a Nd3+ complex with thenoyltrifluoroacetone and 1,10-phenantroline ligands in solution-processed organic light-emitting diodes. Spin-coated blends containing a 1,3-bis(9-carbazolyl)benzene host doped with the Nd3+ complex were found to exhibit a photoluminescence quantum yield of about 0.5%, regardless of the doping concentration level. Electroluminescent devices based on these small molecule blends showed the characteristic emission of Nd3+ at 890, 1060 and 1330 nm with an external quantum efficiency as high as 0.022%. These improved performances were mainly attributed to direct charge trapping and exciton formation on the near infrared emitter. Importantly, the efficiency roll-off at high current densities due to triplet-triplet exciton annihilation in the device containing 20 wt% of the complex was lower than what is typically observed in lanthanide complex-based electroluminescent devices. This is presumably due to the high triplet energy of the host material, which prevents guest-to-host energy-back transfer and thus host-guest triplet-triplet exciton annihilation

1. A 3-week feeding trial with 96 sexed d-old broiler chickens was conducted to examine the effects of microbial phytase supplementation (Natuphos 5000) at 2 dietary energy concentrations on their performance, and the utilisation of nitrogen (N), phosphorus (P), calcium (Ca) and zinc (Zn) and on tibiae ash, Ca, P and Zn concentrations. Four replicate pens (6 birds per pen) of a completely randomised design were used in a 2x2 factorial arrangement of treatments with 2 contents of metabolisable energy (11.72 and 12.55 MJ ME/kg) and 2 additions of phytase (0 and 500 U of microbial phytase/kg). 2. Phytase supplementation significantly improved the utilisation of N, P, Ca and Zn (as a percentage of intake) and increased the concentration of Ca and Zn in the tibiae (P<0.05) because of higher intakes of dry matter, N, P, Ca and Zn. Phytase also significantly reduced the amount of P in the excreta (P<0.05). 3. The AME content of the diet influenced significantly (P<0.05) the excretion of N, P, Ca and Zn and the concentration of P and Ca in tibiae with the birds fed on the high AME diet excreting more minerals and having a smaller percentage of these minerals in their tibiae. However, there were strong interactions between phytase addition and AME in tibia ash and P, with the phytase supplementation producing a higher ash content at the higher AME a and a lower P content at the lower AME.

International audienceHorizontal orientation of light-emitting chromophores plays a critical role in the light outcoupling efficiency and the overall performances of organic light-emitting diodes. Here, we demonstrate that such a horizontal orientation of light-emitting molecules can be achieved in solution-processed blends containing highly fluorescent oligofluorenes dispersed into various small molecule host materials. The influences of the host material, the solvent used for the spin-coating, the doping concentration of the oligofluorenes and the oligofluorene chemical structure on these orientational processes are investigated using variable angle spectroscopic ellipsometry and angle-dependent photoluminescence measurements. By clarifying the roles played by these parameters in the horizontal orientation of the emitters, the results provide crucial insights into these molecular orientational processes in spin-coated glassy organic thin films, which should be relevant for the development of high-efficiency solution-processed organic light-emitting diodes in the near future