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
Single materials that exhibit efficient and stable white-light emission are highly desirable for lighting applications.This paper reports a novel zero-dimensional perovskite,Rb_(4)CdCl_(6):Sn^(2+),Mn^(2+),which demons...Single materials that exhibit efficient and stable white-light emission are highly desirable for lighting applications.This paper reports a novel zero-dimensional perovskite,Rb_(4)CdCl_(6):Sn^(2+),Mn^(2+),which demonstrates exceptional white-light properties including adjustable correlated color temperature,high color rendering index of up to 85,and near-unity photoluminescence quantum yield of 99%.Using a co-doping strategy involving Sn^(2+)and Mn^(2+),cyan-orange dual-band emission with complementary spectral ranges is activated by the self-trapped excitons and d-d transitions of the Sn^(2+)and Mn^(2+)centers in the Rb_(4)CdCl_(6)host,respectively.Intriguingly,although Mn^(2+)ions doped in Rb_(4)CdCl_(6)are difficult to excite,efficient Mn^(2+)emission can be realized through an ultra-high-efficient energy transfer between Sn^(2+)and Mn^(2+)via the formation of adjacent exchange-coupled Sn–Mn pairs.Benefiting from this efficient Dexter energy transfer process,the dual emission shares the same optimal excitation wavelengths of the Sn^(2+)centers and suppresses the non-radiative vibration relaxation significantly.Moreover,the relative intensities of the dual-emission components can be modulated flexibly by adjusting the fraction of the Sn^(2+)ions to the Sn–Mn pairs.This co-doping approach involving short-range energy transfer represents a promising avenue for achieving high-quality white light within a single material.展开更多
Broadband near-infrared(NIR)phosphors are crucial for assembling portable NIR light sources.However,developing efficient and thermally stable broadband NIR phosphors remains challenging.Here,a novel Cr^(3+)-doped garn...Broadband near-infrared(NIR)phosphors are crucial for assembling portable NIR light sources.However,developing efficient and thermally stable broadband NIR phosphors remains challenging.Here,a novel Cr^(3+)-doped garnet phosphor,Gd_(3)Sc_(1.5)In_(0.5)Ga_(3)O_(12):Cr^(3+),is developed by modulating the six-coordinate polyhedral structure.Under 460 nm blue light excitation,it exhibits broadband NIR emission centered at 775 nm with a full width at half maximum(FWHM)exceeding 135 nm,which is attributed to the increased distortion of the B-sites via cation substitution.Specifically,substituting Sc^(3+)with In^(3+)in the designed samples reduces the local site symmetry,overcomes the parity selection rule,and results in greater oscillator strength for electronic transitions,thereby improving optical properties.This leads to an impressive internal quantum efficiency(IQE)of 98.29%,along with excellent thermal stability performance(I_(423 K)=85.50%),which is conducive to practical applications in NIR light sources.The NIR phosphor-converted light-emitting diode(pc-LED)fabricated with the optimized phosphor and a 460 nm blue LED chip demonstrates an outstanding NIR power conversion efficiency(PCE)of 19.75%at 30 mA and an NIR output power of 276.01 mW at 1200 mA.Potential applications in night vision,non-invasive imaging,and non-destructive testing are explored.These results highlight the enhancement of phosphor performance through cation substitution strategies,achieving a balance between QE and thermal stability.These findings are expected to promote the development of NIR pc-LEDs as high-performance light sources for miniaturized NIR spectrometers.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support from the National Natural Science Foundation of China(Grant No.61874074)Science and Technology Project of Shenzhen(Grant No.JCYJ20220531100815034)+1 种基金H.L.acknowledges the support from Technology and Innovation Commission of Shenzhen(20200810164814001)Guangdong Basic and Applied Basic Research Foundation(General Program,Grant No.2022A1515012055).
文摘Single materials that exhibit efficient and stable white-light emission are highly desirable for lighting applications.This paper reports a novel zero-dimensional perovskite,Rb_(4)CdCl_(6):Sn^(2+),Mn^(2+),which demonstrates exceptional white-light properties including adjustable correlated color temperature,high color rendering index of up to 85,and near-unity photoluminescence quantum yield of 99%.Using a co-doping strategy involving Sn^(2+)and Mn^(2+),cyan-orange dual-band emission with complementary spectral ranges is activated by the self-trapped excitons and d-d transitions of the Sn^(2+)and Mn^(2+)centers in the Rb_(4)CdCl_(6)host,respectively.Intriguingly,although Mn^(2+)ions doped in Rb_(4)CdCl_(6)are difficult to excite,efficient Mn^(2+)emission can be realized through an ultra-high-efficient energy transfer between Sn^(2+)and Mn^(2+)via the formation of adjacent exchange-coupled Sn–Mn pairs.Benefiting from this efficient Dexter energy transfer process,the dual emission shares the same optimal excitation wavelengths of the Sn^(2+)centers and suppresses the non-radiative vibration relaxation significantly.Moreover,the relative intensities of the dual-emission components can be modulated flexibly by adjusting the fraction of the Sn^(2+)ions to the Sn–Mn pairs.This co-doping approach involving short-range energy transfer represents a promising avenue for achieving high-quality white light within a single material.
基金supported by the National Natural Science Foundation of China(51972065 and 51802045)Guangzhou Basic and Applied Basic Research Project(202102020871)。
文摘Broadband near-infrared(NIR)phosphors are crucial for assembling portable NIR light sources.However,developing efficient and thermally stable broadband NIR phosphors remains challenging.Here,a novel Cr^(3+)-doped garnet phosphor,Gd_(3)Sc_(1.5)In_(0.5)Ga_(3)O_(12):Cr^(3+),is developed by modulating the six-coordinate polyhedral structure.Under 460 nm blue light excitation,it exhibits broadband NIR emission centered at 775 nm with a full width at half maximum(FWHM)exceeding 135 nm,which is attributed to the increased distortion of the B-sites via cation substitution.Specifically,substituting Sc^(3+)with In^(3+)in the designed samples reduces the local site symmetry,overcomes the parity selection rule,and results in greater oscillator strength for electronic transitions,thereby improving optical properties.This leads to an impressive internal quantum efficiency(IQE)of 98.29%,along with excellent thermal stability performance(I_(423 K)=85.50%),which is conducive to practical applications in NIR light sources.The NIR phosphor-converted light-emitting diode(pc-LED)fabricated with the optimized phosphor and a 460 nm blue LED chip demonstrates an outstanding NIR power conversion efficiency(PCE)of 19.75%at 30 mA and an NIR output power of 276.01 mW at 1200 mA.Potential applications in night vision,non-invasive imaging,and non-destructive testing are explored.These results highlight the enhancement of phosphor performance through cation substitution strategies,achieving a balance between QE and thermal stability.These findings are expected to promote the development of NIR pc-LEDs as high-performance light sources for miniaturized NIR spectrometers.
