Wang Ping, Ge Min, Luo Xiongfei, Zhai Yingxiang, Meckbach Nicolai, Strehmel Veronika, Li Shujun, Chen Zhijun, Strehmel Bernd
Northeast Forestry University, Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, Hexing Road 26, 150040, Harbin, China.
Niederrhein University of Applied Sciences, Department of Chemistry, Institute for Coatings and Surface Chemistry, Adlerstr. 1, D-47798, Krefeld, Germany.
Angew Chem Int Ed Engl. 2024 Sep 23;63(39):e202402915. doi: 10.1002/anie.202402915. Epub 2024 May 15.
Sustainable carbon dots based on cellulose, particularly carboxymethyl cellulose carbon dots (CMCCDs), were confined in an inorganic network resulting in CMCCDs@SiO. This resulted in a material exhibiting long afterglow covering a time frame of several seconds also under air. Temperature-dependent emission spectra gave information on thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) while photocurrent experiments provided a deeper understanding of charge availability in the dark period, and therefore, its availability on the photocatalyst surface. The photo-ATRP initiator, ethyl α-bromophenylacetate (EBPA), quenched the emission from the millisecond to the nanosecond time frame indicating participation of the triplet state in photoinduced electron transfer (PET). Both free radical and controlled radical polymerization based on photo-ATRP protocol worked successfully. Metal-free photo-ATRP resulted in chain extendable macroinitiators based on a reductive mechanism with either MMA or in combination with styrene. Addition of 9 ppm Cu resulted in M/M of 1.4 while an increase to 72 ppm improved uniformity of the polymers; that is M/M=1.03. Complementary experiments with kerria laca carbon dots confined materials, namely KCDs@SiO, provided similar results. Deposition of Cu (9 ppm) on the photocatalyst surface explains better uniformity of the polymers formed in the ATRP protocol.
基于纤维素的可持续碳点，特别是羧甲基纤维素碳点（CMCCD），被限制在无机网络中，形成了CMCCD@SiO。这产生了一种在空气中也能表现出长达几秒余辉的材料。温度依赖发射光谱提供了关于热激活延迟荧光（TADF）和室温磷光（RTP）的信息，而光电流实验则更深入地了解了暗期电荷的可用性，进而了解其在光催化剂表面的可用性。光引发原子转移自由基聚合（photo-ATRP）引发剂α-溴苯乙酸乙酯（EBPA）将发射从毫秒级淬灭到纳秒级，表明三重态参与了光诱导电子转移（PET）。基于photo-ATRP方案的自由基聚合和可控自由基聚合均成功进行。无金属photo-ATRP通过还原机制生成了基于甲基丙烯酸甲酯（MMA）或与苯乙烯组合的可扩链大分子引发剂。添加9 ppm的铜导致多分散指数（M/M）为1.4，而增加到72 ppm则提高了聚合物的均匀性，即M/M = 1.03。对虫胶碳点受限材料（即KCDs@SiO）进行的补充实验提供了类似的结果。在光催化剂表面沉积9 ppm的铜解释了在ATRP方案中形成的聚合物具有更好的均匀性。
