Efficient and almost pure white‐light emission is obtained by combining singlet and triplet emission in a single‐polymer device. The polymers used in this work include a benzothiadiazole group attached to a fluorene backbone and an iridium complex attached to the side chain (see figure). White‐light emission with CIE color coordinates of (0.32, 0.44) and a luminance efficiency of 6.1 cd A–1 is obtained.
Phosphorus-doped graphitic carbon nitrides (P-g-CN) have recently emerged as promising visible-light photocatalysts for both hydrogen generation and clean environment applications because of fast charge carrier transfer and increased light absorption. However, their photocatalytic performances on CO reduction have gained little attention. In this work, phosphorus-doped g-CN nanotubes are synthesized through the one-step thermal reaction of melamine and sodium hypophosphite monohydrate (NaHPO·HO). The phosphine gas generated from the thermal decomposition of NaHPO·HO induces the formation of P-g-CN nanotubes from g-CN nanosheets, leads to an enlarged BET surface area and a unique mesoporous structure, and creates an amino-rich surface. The interstitial doping phosphorus also down shifts the conduction and valence band positions and narrows the band gap of g-CN. The photocatalytic activities are dramatically enhanced in the reduction both of CO to produce CO and CH and of water to produce H because of the efficient suppression of the recombination of electrons and holes. The CO adsorption capacity is improved to 3.14 times, and the production of CO and CH from CO increases to 3.10 and 13.92 times that on g-CN, respectively. The total evolution ratio of CO/CH dramatically decreases to 1.30 from 6.02 for g-CN, indicating a higher selectivity of CH product on P-g-CN, which is likely ascribed to the unique nanotubes structure and amino-rich surface.
Monodisperse polymethacrylate beads of varied size and crosslink density are prepared by emulsion copolymerization of methacrylate and divinyl monomers in the absence of emulsifiers. The sizes of polybutyl and polyethyl methacrylate beads decreased with increasing polymerization temperature, while polymethyl methacrylate beads were largely unchanged in size. The molar mass of polymer in polymethyl metnacrylate beads markedly exceeded that in polystyrene beads. The rate of polymerization increased, and bead size decreased, with increasing initiator concentration or decreasing monomer concentration. The polymethacrylate beads are used as filler particles in polymer composites.
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