Wang, Y.‐L., Liu, B., Yang, J.‐L., Cao, X.‐H., Yang, Y.‐Z., Yang, Q., Greiner, A., Xu, J.‐T., Zhang, X.‐H.
Hyperbranched Fractal Nanocarbons for Bright Photoluminescence in Solid State. Advanced Optical Materials 2019, 1900659.
Nanocarbons with diverse structures have great potential applications in biomedicine, energy conversion, and catalysis owing to their unique photoelectric properties. This work describes bottom‐up synthesis of hyperbranched fractal nanocarbons (HFNs), using trimethylolpropane tri(cyclic carbonate) ether and ethylenediamine as the precursors. HFNs are formed by self‐assembly of in situ generated carbonized polymer dots (CPDs), driven by their low surface ζ‐potentials. Of significance, both CPDs and HFNs possess graphitized carbon core and functionalized shell with core edge layer, thus emit bright solid‐state luminescence with an absolute quantum yield of 11.7% at room temperature and strong phosphorescence at 77 K. The carbonyl cluster of these nanocarbons is mainly responsible for the strong photoluminescence emission. The application of HFNs is demonstrated for energy conversion, using them as single phosphor for fabricating multicolor light‐emitting diodes. This work outlines a fundamental principle to prepare HFNs with bright photoluminescence in solid state.
New Review by S. Agarwal, S. Jiang, Y. Chen published in Macromol. Mater.
S. Agarwal, S. Jiang, Y. Chen
Macromol. Mater. Eng., 2018, 1800548
Welcome to Macromolecular Chemistry II
Spruch der Woche
Perfektion ist erreicht, nicht, wenn sich nichts mehr hinzufügen lässt, sondern, wenn man nichts mehr wegnehmen kann. (Antoine de Saint-Exupery) (Perfection is achieved, not when nothing more can be added, but when nothing more can be taken away (Antoine de Saint-Exupery))
"Die reinste Form des Wahnsinns ist es, alles beim Alten zu lassen und gleichzeitig zu hoffen, dass sich etwas ändert. (The sheerest madness is to leave everything the way it is and to simultaneously hope that something will change)" Albert Einstein
"The fate of genius is to be misunderstood, but not everything is a misunderstood genius" Ralp Waldo Emmerson (1803-1882)
"Facts do not cease to exist because they are ignored” (Aldous Huxley, author of Brave New World)
"Die Ablehnung Unwichtiges zu tun, ist eine entscheidende Voraussetzung für den Erfolg“ Sir Alexander MacKenzie
"An idea that is not dangerous is unworthy of being called an idea at all“ von Oscar Wilde (Eine Idee, die nicht gewagt ist, verdient es nicht, überhaupt eine Idee genannt zu werden)
M. O. Pretscher, T. Chen, G. Sitaru, S. Gekle, J. Ji, S. Agarwal
Precise 2D‐patterned Incompatible Catalysts for Reactions in One‐pot, Chem., 2019.
We show precise and direct two‐dimensional (2D) printing of the incompatible polymer acid‐base catalysts and their utility in one‐pot two‐step reactions. Multi‐step catalytic reactions using incompatible catalysts in a one‐pot reaction cascade require special methods and materials for isolation of catalysts from each other. This, in general is a tedious process requiring special polymer architectures as catalysts’ carrier for preserving the activity of otherwise incompatible catalysts. We propose the immobilization of incompatible polymer catalysts, such as polymer acid and base catalysts, on a substrate in variable sizes and amounts by precise 2D printing. The copolymers with a basic (4‐vinylpyridine) and acidic (styrene sulfonic acid) functionality and methacryloyl benzophenone as a UV cross‐linking unit were used for 2D printing. The printed meshes were immersed together in a reaction solution containing (dimethoxy methyl)‐benzene and ethyl cyanoformate, resulting in a two‐step acid‐base catalyzed cascade reaction, i.e. deacetalization followed by carbon‐building reaction. The time‐dependent consumption of (dimethoxymethyl)‐benzene to the intermediate benzaldehyde and the product was monitored, and a kinetic model was developed to investigate the underlying reaction dynamics. The complexity of multi‐step Wolf‐Lamb‐type reactions was generally significantly decreased using our approach due to the easy polymerization and immobilization procedure.