CsPbI_(3)perovskite quantum dots(QDs)have great potential in optoelectronic devices due to their suitable band-gaps,but low photoluminescence quantum yields(PLQYs)and poor phase stability seriously impede their practi...CsPbI_(3)perovskite quantum dots(QDs)have great potential in optoelectronic devices due to their suitable band-gaps,but low photoluminescence quantum yields(PLQYs)and poor phase stability seriously impede their practical application.This paper reports the synthesis of Ce^(3+)-doped CsPbI_(3)QDs by a hot injection method.In the presence of the dopant(Ce^(3+)),the highest PLQY of CsPbI_(3)QDs reached 99%,i.e.,near-unity PLQY,and the photoluminescence(PL)emission of CsPbI_(3)QDs could be well maintained compared to that of the undoped ones.The photoluminescence kinetics of Ce^(3+)-doped CsPbI_(3)QDs was investigated by the ultrafast transient absorption technologies,which exhibited that the Ce^(3+)not only increased the density of excitonic states close to the high energy excitonic states(HES),but also provided more emissive channels.Moreover,the radiative recombination rates calculated by the combination of PL lifetime and PLQY further illustrated the Pb2+vacancies were filled with Ce^(3+)ions so that the PL quenching of the CsPbI_(3)QDs could be effectively prevented.The theoretic analysis uncovered the mechanism of the high PLQY and stable PL emission of the Ce^(3+)-doped CsPbI_(3)QDs.展开更多
Luminescent open-shell organic radicals have recently been regarded as one of the most potential materials in organic light-emitting diodes(OLEDs).Herein,we have synthesized two new organic radicals,namely tris{4-[4-(...Luminescent open-shell organic radicals have recently been regarded as one of the most potential materials in organic light-emitting diodes(OLEDs).Herein,we have synthesized two new organic radicals,namely tris{4-[4-(tert-butyl)phenoxy]-2,6-dichlorophenyl}methane radical(TTM-O)and tris(4-{[4-(tert-butyl)-phenyl]thio}-2,6-dichlorophenyl)methane radical(TTM-S),by the substitution of chalcogen atom elements at the para position of conventional tris(2,4,6-trichlorophenyl)methyl(TTM)radical moiety.Interestingly,both TTM-O and TTM-S exhibited significantly enhanced photostability compared with the unsubstituted TTM radical parent.Moreover,the chalcogen atom also had a crucial impact on the photoluminescence quantum yield(PLQY)of the radicals,i.e.,the PLQY of TTM-S was greatly enhanced compared to TTM radical while TTM-O was nearly non-emissive.Particularly,TTM-S showed intense PLQY of 37.54%and 185-fold longer photostability than that in cyclohexane solution of TTM.展开更多
Electrogenerated chemiluminescence(ECL)has been extensively used in ultrasensitive electroanalysis because it can be generated electrochemically without using expensive optics and light sources.Visible ECL emission ca...Electrogenerated chemiluminescence(ECL)has been extensively used in ultrasensitive electroanalysis because it can be generated electrochemically without using expensive optics and light sources.Visible ECL emission can be obtained with a reasonable quantum yield and stability.Blue ECL is rare and often suffers from stability and poor quantum efficiency.Blue ECL emission at 473 nm from organometallic halide perovskite nanocrystals(PNCs),CH_(3)NH_(3)PbCl_(1.08)Br_(1.92),is reported here for the first time using tripropylamine(TPrA)as co-reactant.The blue ECL emission peak resembles its photoluminescence peak position.In addition to this blue emission peak,the ECL spectra of CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs also showed a broad ECL peak at 745 nm.Generation of the second ECL peak at 745 nm from CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs was can be explained by the existence of surface trap states on as-synthesized PNC due to incomplete surface passivation.Halide anion tunability of ECL emission from CH3NH3PbX3(X:Cl,Br,I)PNCs is also demonstrated.The fluorescence microscopy image of single PNC and stability of selected single PNCs are presented in this with simultaneous acquisition of fluorescence spectra using 405-nm laser excitation.The photoluminescence(PL)decay was described by PL lifetime(τ)of 1.2 ns.The effect of the addition of surfactants(oleic acid and n-octylamine)on the fluorescence intensity and stability of CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs is also discussed.展开更多
基金This work was finanicially supported by the Key Research and Development Project of Anhui Province of China(No.1704a0902023)the Open Research Fund of State Key Laboratory of Plused Power Laser Technology(No.SKL2019KF09)。
文摘CsPbI_(3)perovskite quantum dots(QDs)have great potential in optoelectronic devices due to their suitable band-gaps,but low photoluminescence quantum yields(PLQYs)and poor phase stability seriously impede their practical application.This paper reports the synthesis of Ce^(3+)-doped CsPbI_(3)QDs by a hot injection method.In the presence of the dopant(Ce^(3+)),the highest PLQY of CsPbI_(3)QDs reached 99%,i.e.,near-unity PLQY,and the photoluminescence(PL)emission of CsPbI_(3)QDs could be well maintained compared to that of the undoped ones.The photoluminescence kinetics of Ce^(3+)-doped CsPbI_(3)QDs was investigated by the ultrafast transient absorption technologies,which exhibited that the Ce^(3+)not only increased the density of excitonic states close to the high energy excitonic states(HES),but also provided more emissive channels.Moreover,the radiative recombination rates calculated by the combination of PL lifetime and PLQY further illustrated the Pb2+vacancies were filled with Ce^(3+)ions so that the PL quenching of the CsPbI_(3)QDs could be effectively prevented.The theoretic analysis uncovered the mechanism of the high PLQY and stable PL emission of the Ce^(3+)-doped CsPbI_(3)QDs.
基金National Natural Science Foundation of China(No.52003081)Shanghai Natural Science Foundation,China(No.22ZR1420600).
文摘Luminescent open-shell organic radicals have recently been regarded as one of the most potential materials in organic light-emitting diodes(OLEDs).Herein,we have synthesized two new organic radicals,namely tris{4-[4-(tert-butyl)phenoxy]-2,6-dichlorophenyl}methane radical(TTM-O)and tris(4-{[4-(tert-butyl)-phenyl]thio}-2,6-dichlorophenyl)methane radical(TTM-S),by the substitution of chalcogen atom elements at the para position of conventional tris(2,4,6-trichlorophenyl)methyl(TTM)radical moiety.Interestingly,both TTM-O and TTM-S exhibited significantly enhanced photostability compared with the unsubstituted TTM radical parent.Moreover,the chalcogen atom also had a crucial impact on the photoluminescence quantum yield(PLQY)of the radicals,i.e.,the PLQY of TTM-S was greatly enhanced compared to TTM radical while TTM-O was nearly non-emissive.Particularly,TTM-S showed intense PLQY of 37.54%and 185-fold longer photostability than that in cyclohexane solution of TTM.
基金We would like to thank the financial support from the National Science Foundation(NSF award CHE 1508192 and OIA-1539035).
文摘Electrogenerated chemiluminescence(ECL)has been extensively used in ultrasensitive electroanalysis because it can be generated electrochemically without using expensive optics and light sources.Visible ECL emission can be obtained with a reasonable quantum yield and stability.Blue ECL is rare and often suffers from stability and poor quantum efficiency.Blue ECL emission at 473 nm from organometallic halide perovskite nanocrystals(PNCs),CH_(3)NH_(3)PbCl_(1.08)Br_(1.92),is reported here for the first time using tripropylamine(TPrA)as co-reactant.The blue ECL emission peak resembles its photoluminescence peak position.In addition to this blue emission peak,the ECL spectra of CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs also showed a broad ECL peak at 745 nm.Generation of the second ECL peak at 745 nm from CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs was can be explained by the existence of surface trap states on as-synthesized PNC due to incomplete surface passivation.Halide anion tunability of ECL emission from CH3NH3PbX3(X:Cl,Br,I)PNCs is also demonstrated.The fluorescence microscopy image of single PNC and stability of selected single PNCs are presented in this with simultaneous acquisition of fluorescence spectra using 405-nm laser excitation.The photoluminescence(PL)decay was described by PL lifetime(τ)of 1.2 ns.The effect of the addition of surfactants(oleic acid and n-octylamine)on the fluorescence intensity and stability of CH_(3)NH_(3)PbCl_(1.08)Br_(1.92) PNCs is also discussed.
