excitation beam still remained after the second scan. Demonstrations of effi cient persistent RTP in pure organic host-guest fi lms showing other phosphorescence colors are shown in Supporting Information Movies S1 to S4. In addition to long RTP lifetimes (a few seconds), these materials have RTP quantum effi ciencies of > 10% for RGB RTP in air.www.afm-journal.de www.MaterialsViews.com wileyonlinelibrary.com

Efficient organic light-emitting diodes have been developed using emitters containing rare metals, such as platinum and iridium complexes. However, there is an urgent need to develop emitters composed of more abundant materials. Here we show a thermally activated delayed fluorescence material for organic light-emitting diodes, which realizes both approximately 100% photoluminescence quantum yield and approximately 100% up-conversion of the triplet to singlet excited state. The material contains electron-donating diphenylaminocarbazole and electron-accepting triphenyltriazine moieties. The typical trade-off between effective emission and triplet-to-singlet up-conversion is overcome by fine-tuning the highest occupied molecular orbital and lowest unoccupied molecular orbital distributions. The nearly zero singlet–triplet energy gap, smaller than the thermal energy at room temperature, results in an organic light-emitting diode with external quantum efficiency of 29.6%. An external quantum efficiency of 41.5% is obtained when using an out-coupling sheet. The external quantum efficiency is 30.7% even at a high luminance of 3,000 cd m−2.

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A new method of producing carbon-centered radicals was discovered through the reaction of an alkyl iodide (R-I) with organic salts to reversibly generate the corresponding alkyl radical (R(•)). Via this new reaction, the organic salts were used as new and highly efficient organic catalysts in living radical polymerization. The catalysts included common and inexpensive compounds such as tetrabutylammonium iodide and methyltributylphosphonium iodide. Notably, the catalysts were highly reactive. They enabled the synthesis of high-molecular-weight polymers (up to Mn = 140,000) and the control of acrylate polymerization, which had been difficult with other organic catalysts. The organic salt catalysts were highly versatile, reacting with methacrylate, acrylate, styrene, acrylonitrile, and functional methacrylate monomers. Well-defined block copolymers were also prepared by using this method. A kinetic study quantitatively confirmed the high reactivity of these catalysts. Attractive features of this system include its low cost, its ease of operation, and its ability to access a wide range of polymer designs.

Photocontrolled organocatalyzed living radical polymerization was conducted over a wide range of irradiation wavelengths (350-750 nm). The polymerization was induced and controlled at the desired wavelengths by exploiting suitable organic catalysts. This system was finely responsive to the irradiation wavelength; the polymerization was instantly switched on and off, and the polymerization rate was sensitively modulated by altering the irradiation wavelength. The polymer molecular weight and its distribution (M(w)/M(n) = 1.1-1.4) were well controlled for methacrylate monomers up to fairly high conversions in many cases. The monomer scope encompassed various functional methacrylates, and their block copolymers were obtained. The feasibility of such a wide range of wavelengths and the fine response to the wavelength are unprecedented features. As a unique application of the wavelength-responsive nature of this system, we demonstrated "one-pot" selective regulation of living radical polymerization and another type of polymerization (ring opening polymerization), where the regulation was achieved by simply altering the irradiation wavelength. Facile operation and applicability to a wide range of polymer designs are advantages of this polymerization.

The separation of oil and water is an important pursuit for saving endangered environments. In 2010, the Gulf of Mexico oil spill widely and seriously damaged the ocean and coast near the oilfield. The number of similar accidents is increasing with the development of industry, and materials that can reduce environmental pollution are in high demanded. At the same time, in the area of analytical chemistry, the efficient separation of molecules is a key technique, which determines the efficiency and accuracy of chemical analysis and detection. For these purposes, hydrophobic porous materials are in common use, because hydrophobic surfaces effectively adsorb/absorb oily target compounds that are mixed with an aqueous phase. Therefore, many researchers have been studying hydrophobic porous materials and their application as oil/water separation media. [1] Various chemical compositions have been investigated, such as carbon-based materials, [2] metal oxide nanowires (such as manganese [3,4] ), biomass nanofibers (such as cellulose [5,6] ), organic polymers (such as polyester, [7] polydivinylbenzene, and polythiophene [8] ) and hydrophobic macroporous aerogels. [9,10] Other materials based on polydimethylsiloxane (PDMS) or fluorocarboncoated materials, [3,7,10, 11] and the design of a biomimetic rough surface, through the use of etching techniques, to enhance hydrophobicity [6,12] are also widely reported. However, these methods have problems such as complicated and lengthy processes and high costs for reagents and devices, which prevents the use of these materials in practical and commercial applications.We have investigated hydrophobic porous polymethylsilsesquioxane (PMSQ, CH 3 SiO 1.5 ) materials, derived from methyltrimethoxysilane (MTMS), consisting of transparent aerogels and xerogels with mesoporous to macroporous monoliths that are created by controlling phase separation in the sol-gel process. [13] Polymethylsilsesquioxane gels have a superhydrophobic surface owing to methyl groups that are directly bonded to silicon atoms; this flexible network structure allows the material to spring back after compression. This mechanical feature allows the preparation of aerogel-like xerogels by ambient-pressure drying. Last year, we first reported bendable, marshmallow-like porous gels derived from a co-precursor system of MTMS and dimethyldimethoxysilane (DMDMS) in almost the same way as PMSQ gels. [14] Marshmallow-like gels not only show compression/ reexpansion properties similar to that of PMSQ gels, but also very soft and bendable mechanical features. A high sound absorption property has also been previously reported, owing to the soft networks. The flexiblity and intrinsic hydrophobicity indicate that these materials can be used like a sponge as an adsorption/absorption media for the quick removal of unwanted organic liquids. Herein, we report the outstanding capability of these materials for absorbing organic liquids over a wide temperature range, and discuss the possibility for their application as separation me...

Aerogels have many attractive properties but are usually costly and mechanically brittle, which always limit their practical applications. While many efforts have been made to reinforce the aerogels, most of the reinforcement efforts sacrifice the transparency or superinsulating properties. Here we report superflexible polyvinylpolymethylsiloxane, (CHCH(Si(CH)O)), aerogels that are facilely prepared from a single precursor vinylmethyldimethoxysilane or vinylmethyldiethoxysilane without organic cross-linkers. The method is based on consecutive processes involving radical polymerization and hydrolytic polycondensation, followed by ultralow-cost, highly scalable, ambient-pressure drying directly from alcohol as a drying medium without any modification or additional solvent exchange. The resulting aerogels and xerogels show a homogeneous, tunable, highly porous, doubly cross-linked nanostructure with the elastic polymethylsiloxane network cross-linked with flexible hydrocarbon chains. An outstanding combination of ultralow cost, high scalability, uniform pore size, high surface area, high transparency, high hydrophobicity, excellent machinability, superflexibility in compression, superflexibility in bending, and superinsulating properties has been achieved in a single aerogel or xerogel. This study represents a significant progress of porous materials and makes the practical applications of transparent flexible aerogel-based superinsulators realistic.

Triarylboron compounds have attracted much attention, and found wide use as functional materials because of their electron-accepting properties arising from the vacant p orbitals on the boron atoms. In this study, we design and synthesize new donor-acceptor triarylboron emitters that show thermally activated delayed fluorescence. These emitters display sky-blue to green emission and high photoluminescence quantum yields of 87-100 % in host matrices. Organic light-emitting diodes using these emitting molecules as dopants exhibit high external quantum efficiencies of 14.0-22.8 %, which originate from efficient up-conversion from triplet to singlet states and subsequent efficient radiative decay from singlet to ground states.