Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a fac...Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots(CDs) through in situ embedding o-CDs(being prepared from o-phenylenediamine) into cyanuric acid(CA) matrix(named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) of o-CDs,respectively. In addition,the formation of covalent bonds between o-CDs and CA,and the presence of multiple fixation and rigid e ects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA,it is completely covered by the green TADF during directly observing. The NIR RTP signal,however,can be readily captured if an optical filter(cut-o wavelength of 600 nm) being used. By utilizing these unique features,the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally,the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.展开更多
Materials with controllable luminescence colors are highly desirable for numerous promising applications, however, the preparation of such materials, particularly with color-controllable room-temperature phosphorescen...Materials with controllable luminescence colors are highly desirable for numerous promising applications, however, the preparation of such materials, particularly with color-controllable room-temperature phosphorescence(RTP), remains a formidable challenge. In this work, we reported on a facile strategy to prepare color-controllable RTP materials via the pyrolysis of a mixture containing 1-(2-hydroxyethyl)-urea(H-urea) and boric acid(BA). By controlling the pyrolysis temperatures, the as-prepared materials exhibited ultralong RTP with emission colors ranging from cyan, green, to yellow. Further studies revealed that multiple luminescent centers formed from H-urea, which were in-situ embedded in the B2O3matrix(produced from BA) during the pyrolysis process. The contents of the different luminescent centers could be regulated by the pyrolysis temperatures, resulting in color-tunable RTP. Significantly, the luminescent center engineering and in-situ immobilization strategy not only provided a facile method for conveniently preparing color-controllable RTP materials, but also endowed the materials prepared at relatively lower temperatures with color-changeable RTP features under thermal stimulus. Considering their unique properties, the potential applications of the as-obtained materials for advanced anti-counterfeiting and information encryption were preliminarily demonstrated.展开更多
The first carbon dot(CD)-based organic long persistent luminescence(OLPL)system exhibiting more than 1 h of duration was developed.In contrast to the established OLPL systems,herein,the reported CDs-based system(named...The first carbon dot(CD)-based organic long persistent luminescence(OLPL)system exhibiting more than 1 h of duration was developed.In contrast to the established OLPL systems,herein,the reported CDs-based system(named m-CDs@CA)can be facilely and effectively fabricated using a household microwave oven,and more impressively,its LPL can be observed under ambient conditions and even in aqueous media.XRD and TEM characterizations,afterglow decay,time-resolved spectroscopy,and ESR analysis were performed,showing the successful composition of CDs and.CA,the formation of exciplexes and long-lived charged-separated states.Further studies suggest that the production of covalent bonds between CA and CDs plays pivotal roles in activating LPL and preventing its quenching from oxygen and water.To the best of our knowledge,this is a very rare example of an OLPL system that exhibits hourlevel afterglow under ambient conditions.Finally,applications of m-CDs@C.A in glow-in-the-dark paints for emergency signs and multicolored luminous pearls were preliminarily demonstrated.This work may provide new insights for the development of rare earth-free and robust OLPL materials.展开更多
基金the National Natural Science Foundation of China (52003284,51872300 and U1832110)the China Postdoctoral Science Foundation (BX20190338)S&T Innovation 2025 Major Special Program of Ningbo (2018B10054) for financially supporting this work。
文摘Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots(CDs) through in situ embedding o-CDs(being prepared from o-phenylenediamine) into cyanuric acid(CA) matrix(named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) of o-CDs,respectively. In addition,the formation of covalent bonds between o-CDs and CA,and the presence of multiple fixation and rigid e ects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA,it is completely covered by the green TADF during directly observing. The NIR RTP signal,however,can be readily captured if an optical filter(cut-o wavelength of 600 nm) being used. By utilizing these unique features,the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally,the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.
基金the National Natural Science Foundation of China (Nos. 51872300 and 52003284)the Natural Science Foundation of Jiangsu Province (No. BK20210481)the Fundamental Research Fund of Jiangnan University (No. JUSRP122015) for financially supporting this work。
文摘Materials with controllable luminescence colors are highly desirable for numerous promising applications, however, the preparation of such materials, particularly with color-controllable room-temperature phosphorescence(RTP), remains a formidable challenge. In this work, we reported on a facile strategy to prepare color-controllable RTP materials via the pyrolysis of a mixture containing 1-(2-hydroxyethyl)-urea(H-urea) and boric acid(BA). By controlling the pyrolysis temperatures, the as-prepared materials exhibited ultralong RTP with emission colors ranging from cyan, green, to yellow. Further studies revealed that multiple luminescent centers formed from H-urea, which were in-situ embedded in the B2O3matrix(produced from BA) during the pyrolysis process. The contents of the different luminescent centers could be regulated by the pyrolysis temperatures, resulting in color-tunable RTP. Significantly, the luminescent center engineering and in-situ immobilization strategy not only provided a facile method for conveniently preparing color-controllable RTP materials, but also endowed the materials prepared at relatively lower temperatures with color-changeable RTP features under thermal stimulus. Considering their unique properties, the potential applications of the as-obtained materials for advanced anti-counterfeiting and information encryption were preliminarily demonstrated.
基金the National Natural Science Foundation of China(52003284,51872300,and U1832110)the China Postdoctoral Science Foundation(BX20190338)the S&T Innovation 2025 Major Special Programme of Ningbo(2018B10054)for financially supporting this work.
文摘The first carbon dot(CD)-based organic long persistent luminescence(OLPL)system exhibiting more than 1 h of duration was developed.In contrast to the established OLPL systems,herein,the reported CDs-based system(named m-CDs@CA)can be facilely and effectively fabricated using a household microwave oven,and more impressively,its LPL can be observed under ambient conditions and even in aqueous media.XRD and TEM characterizations,afterglow decay,time-resolved spectroscopy,and ESR analysis were performed,showing the successful composition of CDs and.CA,the formation of exciplexes and long-lived charged-separated states.Further studies suggest that the production of covalent bonds between CA and CDs plays pivotal roles in activating LPL and preventing its quenching from oxygen and water.To the best of our knowledge,this is a very rare example of an OLPL system that exhibits hourlevel afterglow under ambient conditions.Finally,applications of m-CDs@C.A in glow-in-the-dark paints for emergency signs and multicolored luminous pearls were preliminarily demonstrated.This work may provide new insights for the development of rare earth-free and robust OLPL materials.
