Achieving color-tunable room-temperature phosphorescence(RTP),especially including blue RTP from a single-component polymer still faces a formidable challenge.Herein,we wisely choose conformation-dependent phenothiazi...Achieving color-tunable room-temperature phosphorescence(RTP),especially including blue RTP from a single-component polymer still faces a formidable challenge.Herein,we wisely choose conformation-dependent phenothiazine with trifluoromethyl substituent as the side group of the phosphor monomer(Cz PT)and then copolymerize it with N-isopropylacrylamide(NIPAM)through photopolymerization to obtain polymers PPCz PTs.Time-dependent color-tunable phosphorescence from unusual quasi-equatorial(eq)to quasi-axial(ax)conformers are obtained,and the RTP color changes from orange(550 nm)to blue(470 nm)with phosphorescence lifetime up to 0.96 s.The theoretical calculations confirm that the quasi-axial conformer is the preferred structure that facilitates the formation of intramolecular hydrogen bonds on the trifluoromethyl group.The EPR spectra illustrate that the persistent UV irradiation generates radical cations to induce the conformational transitions first,followed by photopolymerization immobilizing the ax conformation in PPCz PTs.Applications of data encryption and anti-counterfeiting are fabricated to show prompt and delayed multicolor information.This work affords a simple and feasible avenue for two-dimensional color tunable room temperature phosphorescence from a single-component polymer.展开更多
Efficient polymeric room-temperature phosphorescence(PRTP)with excellent processability and flexibility is highly desirable but still faces formidable challenge.Herein,a general strategy is developed for efficient PRT...Efficient polymeric room-temperature phosphorescence(PRTP)with excellent processability and flexibility is highly desirable but still faces formidable challenge.Herein,a general strategy is developed for efficient PRTP through photo-polymerization of phosphor monomers and N-isopropylacrylamide(NIPAM)spontaneously without a crosslinker.Remarkably ultralong lifetime of 3.54 s with afterglow duration time of 25 s and decent phosphorescent quantum efficiency of 13%are achieved.This efficient PRTP has been demonstrated to be derived from the synergistic effect of the covalent and hydrogen bonds networks formed through photo-polymerization of NIPAM.The electron paramagnetic resonance(EPR)spectra confirmed that methyl radicals are generated under the irradiation of ultraviolet light and promote the formation of covalent cross-linking networks.This strategy has also been proved to be generalizable to several other phosphor monomers.Interestingly,the polymer films display ultrahigh temperature resistance with long afterglows even at 140℃ and unexampled ultralong lifetime of 2.45 s in aqueous solutions.This work provides a simple and feasible avenue to obtain efficient PRTP.展开更多
基金supported by the National Natural Science Foundation of China (22175149)the Natural Science Foundation of Hunan Province (NSFH 2021JJ30661)。
文摘Achieving color-tunable room-temperature phosphorescence(RTP),especially including blue RTP from a single-component polymer still faces a formidable challenge.Herein,we wisely choose conformation-dependent phenothiazine with trifluoromethyl substituent as the side group of the phosphor monomer(Cz PT)and then copolymerize it with N-isopropylacrylamide(NIPAM)through photopolymerization to obtain polymers PPCz PTs.Time-dependent color-tunable phosphorescence from unusual quasi-equatorial(eq)to quasi-axial(ax)conformers are obtained,and the RTP color changes from orange(550 nm)to blue(470 nm)with phosphorescence lifetime up to 0.96 s.The theoretical calculations confirm that the quasi-axial conformer is the preferred structure that facilitates the formation of intramolecular hydrogen bonds on the trifluoromethyl group.The EPR spectra illustrate that the persistent UV irradiation generates radical cations to induce the conformational transitions first,followed by photopolymerization immobilizing the ax conformation in PPCz PTs.Applications of data encryption and anti-counterfeiting are fabricated to show prompt and delayed multicolor information.This work affords a simple and feasible avenue for two-dimensional color tunable room temperature phosphorescence from a single-component polymer.
基金supported by the National Natural Science Foundation of China(22175149,21975215)the Natural Science Foundation of Hunan Province(2021JJ30661)the Scientific Research Foundation of Hunan Provincial Education Department(19A486)。
文摘Efficient polymeric room-temperature phosphorescence(PRTP)with excellent processability and flexibility is highly desirable but still faces formidable challenge.Herein,a general strategy is developed for efficient PRTP through photo-polymerization of phosphor monomers and N-isopropylacrylamide(NIPAM)spontaneously without a crosslinker.Remarkably ultralong lifetime of 3.54 s with afterglow duration time of 25 s and decent phosphorescent quantum efficiency of 13%are achieved.This efficient PRTP has been demonstrated to be derived from the synergistic effect of the covalent and hydrogen bonds networks formed through photo-polymerization of NIPAM.The electron paramagnetic resonance(EPR)spectra confirmed that methyl radicals are generated under the irradiation of ultraviolet light and promote the formation of covalent cross-linking networks.This strategy has also been proved to be generalizable to several other phosphor monomers.Interestingly,the polymer films display ultrahigh temperature resistance with long afterglows even at 140℃ and unexampled ultralong lifetime of 2.45 s in aqueous solutions.This work provides a simple and feasible avenue to obtain efficient PRTP.
