Kumari Rinki, Kumar Ashok, Mishra Neeraj Kumar, Sahu Sumanta Kumar
Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand, India.
Optical Materials and Bioimaging Research Laboratory, Department of Physics, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand, India.
Langmuir. 2022 Aug 2;38(30):9389-9399. doi: 10.1021/acs.langmuir.2c01351. Epub 2022 Jul 19.
Exploration of many strategies has continuously contributed to producing aggregation-induced red-emissive carbon dots (CDs). In this work, we designed fluorine-embedded (F-embedded) CDs from 1,2,4-triaminobenzene, thiourea, and ammonium fluoride (NHF) exhibiting polymer-induced emission (PIE). The PIE phenomenon of fluorescent CDs is obtained in poly(vinyl alcohol) (PVA), showing emissions at 611 and 617 nm in the dispersed and solid states, respectively. The CDs exhibited a red shift of 28 nm in the PVA solution because PVA hydroxyl groups formed a robust bridge-like H-bonding network between CDs. The fluorine embedded in CDs enhanced the H-bond affinity toward PVA. It showed that this H-bond restricted the coupling of CDs' surface states and inhibited the nonirradiation transfer. For the solid state, surface PVA chains eliminated the π-π interaction of the conjugated core and constructed a self-quenching resistance polymeric system around CDs. As a result, CDs showed an unexpected red shift of fluorescence emission in PVA. Furthermore, white light-emitting diodes (WLEDs) have a correlated color temperature (CCT) of 5232 K, and a high color rendering index of 95 has been fabricated by integrating the red- and green-emissive films over the UV LEDs. Interestingly, the as-synthesized CDs showed room temperature phosphorescence (RTP), which enabled us to employ the CDs in double-security protection. Simultaneously, CDs have been used in fingerprint detection.
对多种策略的探索不断推动了聚集诱导发红光碳点（CDs）的制备。在这项工作中，我们以1,2,4 - 三氨基苯、硫脲和氟化铵（NH₄F）为原料设计了氟嵌入（F - 嵌入）的CDs，其表现出聚合物诱导发光（PIE）。荧光CDs的PIE现象在聚乙烯醇（PVA）中得以实现，在分散态和固态下分别在611 nm和617 nm处发光。CDs在PVA溶液中出现了28 nm的红移，这是因为PVA羟基在CDs之间形成了坚固的桥状氢键网络。嵌入CDs中的氟增强了对PVA的氢键亲和力。这表明这种氢键限制了CDs表面态的耦合并抑制了非辐射转移。对于固态，表面的PVA链消除了共轭核心的π - π相互作用，并在CDs周围构建了一个抗自猝灭的聚合物体系。结果，CDs在PVA中呈现出意想不到的荧光发射红移。此外，通过在紫外发光二极管上集成红色和绿色发光膜，制备出了相关色温（CCT）为5232 K且显色指数高达95的白色发光二极管（WLEDs）。有趣的是，合成的CDs表现出室温磷光（RTP），这使我们能够将CDs用于双重安全保护。同时，CDs已被用于指纹检测。
