Chongqing University of Technology

About: Chongqing University of Technology is a education organization based out in Chongqing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 5199 authors who have published 4205 publications receiving 35954 citations. The organization is also known as: Chongqing Institute of Technology.

Large-Area, Flexible, Transparent, and Long-Lived Polymer-Based Phosphorescence Films.

Abstract: Polymer-based room-temperature phosphorescence (RTP) materials with high flexibility and large-area producibility are highly promising for applications in organic electronics. However, achieving such photophysical materials is challenging because of difficulties in populating and stabilizing susceptible triplet excited states at room temperature. Herein large-area, flexible, transparent, and long-lived RTP systems prepared by doping rationally selected organic chromophores in a poly(vinyl alcohol) (PVA) matrix were realized through a hydrogen-bonding and coassembly strategy. In particular, the 3,6-diphenyl-9H-carbazole (DPCz)-doped PVA film shows long-lived phosphorescence emission (up to 2044.86 ms) and a remarkable duration of afterglow (over 20 s) under ambient conditions. Meanwhile, the 7H-dibenzo[c,g]carbazole (DBCz)-doped PVA film exhibits high absolute luminance of 158.4 mcd m2 after the ultraviolet excitation source is removed. The RTP results not only from suppressing the nonradiative decay by abundant hydrogen-bonding interactions in the PVA matrix but also from minimizing the energy gap (ΔEST) between the singlet state and the triplet state through the coassembly effect. On account of the outstanding mechanical properties and the afterglow performance of these RTP materials, they were applied in the fabrication of flexible 3D objects with repeatable folding and curling properties. Importantly, the multichannel afterglow light-emitting diode arrays were established under ambient conditions. The present long-lived phosphorescent systems demonstrate a bright opportunity for the production of large-area, flexible, and transparent emitting materials.

Ultraviolet irradiation-responsive dynamic ultralong organic phosphorescence in polymeric systems.

Abstract: Room temperature phosphorescence (RTP) has drawn extensive attention in recent years. Efficient stimulus-responsive phosphorescent organic materials are attractive, but are extremely rare because of unclear design principles and intrinsically spin-forbidden intersystem crossing. Herein, we present a feasible and facile strategy to achieve ultraviolet irradiation-responsive ultralong RTP (IRRTP) of some simple organic phosphors by doping into amorphous poly(vinyl alcohol) matrix. In addition to the observed green and yellow afterglow emission with distinct irradiation-enhanced phosphorescence, the phosphorescence lifetime can be tuned by varying the irradiation period of 254 nm light. Significantly, the dynamic phosphorescence lifetime could be increased 14.3 folds from 58.03 ms to 828.81 ms in one of the obtained hybrid films after irradiation for 45 min under ambient conditions. As such, the application in polychromatic screen printing and multilevel information encryption is demonstrated. The extraordinary IRRTP in the amorphous state endows these systems with a highly promising potential for smart flexible luminescent materials and sensors with dynamically controlled phosphorescence. Efficient stimulus-responsive phosphorescence organic materials are attractive, but are extremely rare because of unclear design principles and intrinsically spin-forbidden intersystem crossing. Here, the authors present a facile strategy to achieve ultraviolet irradiation-responsive ultralong room-temperature phosphorescence in several simple amorphous polymer materials.

Self-Assembled Asymmetric Block Copolymer Membranes: Bridging the Gap from Ultra- to Nanofiltration

Abstract: The self-assembly of block copolymers is an emerging strategy to produce isoporous ultrafiltration membranes However, thus far, it has not been possible to bridge the gap from ultra- to nanofiltration and decrease the pore size of self-assembled block copolymer membranes to below 5 nm without post-treatment It is now reported that the self-assembly of blends of two chemically interacting copolymers can lead to highly porous membranes with pore diameters as small as 15 nm The membrane containing an ultraporous, 60 nm thin separation layer can fully reject solutes with molecular weights of 600 g mol(-1) in aqueous solutions with a water flux that is more than one order of magnitude higher than the permeance of commercial nanofiltration membranes Simulations of the membrane formation process by dissipative particle dynamics (DPD) were used to explain the dramatic observed pore size reduction combined with an increase in water flux