Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed...Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed acetone on three SrTiO_(3)morphologies:cubes(for which exclusively{100}facets are exposed),{110}-truncated cubes,and{100}-truncated rhombic dodecahedrons,respectively,all prepared by hydrothermal synthesis.In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy shows that cubic crystals contain a high quantity of surface-OH groups,enabling significant quantities of adsorbed acetone in the form ofη^(1)-enolate when exposed to gas phase acetone.Contrary,{110}facets exhibit fewer surface-OH groups,resulting in relatively small quantities of adsorbedη^(1)-acetone,without observable quantities of enolate.Interestingly,acetate and formate signatures appear in the spectra of cubic,surfaceη^(1)-enolate containing,SrTiO_(3)upon illumination,while besides acetate and formate,the formation of(surface)formaldehyde was observed on truncated cubes,and dodecahedrons,by conversion of adsorbedη^(1)-acetone.Time-Resolved Photoluminescence studies demonstrate that the lifetimes of photogenerated charge carriers vary with crystal morphology.The shortest carrier lifetime(τ_(1)=33±0.1 ps)was observed in{110}-truncated cube SrTiO_(3),likely due to a relatively strong built-in electric field promoting electron transport to{100}facets and hole transport to{110}facets.The second lifetime(τ_(2)=259±1 ps)was also the shortest for this morphology,possibly due to a higher amount of surface trap states.Our results demonstrate that SrTiO_(3)crystal morphology can be tuned to optimize performance in photocatalytic oxidation.展开更多
Luminescence decay and time resolved photoluminescence(TRPL) spectra are used for study on the transient luminescence process of the nominally disordered GaInP alloy. The luminescence decay of GaInP alloy shows the te...Luminescence decay and time resolved photoluminescence(TRPL) spectra are used for study on the transient luminescence process of the nominally disordered GaInP alloy. The luminescence decay of GaInP alloy shows the temperature and excitation intensity dependent characters. At 77 K and under high excitation intensity, the luminescence decay shows single exponential time dependence, while under low excitation intensity or at 300 K, the luminescence decay shows double exponential time dependence. The analysis indicates that this nominally disordered GaInP alloy actually exhibits a very weak degree of order. The blue shift of PL peak is observed in the TRPL spectra at 77 K, which is derived from the transfer of the carriers from the ordered domain to the disordered region of the alloy. At 300 K, due to the thermal quenching, the transfer is too weak to be observed. However, The recombination of the carriers between the ordered domain and the disordered region is still devoted to luminesce.展开更多
As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. T...As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. The perovskite materials with ID and 2D shapes were widely prepared and studied for Fabry-Perot mode and whispering-gallery-mode (WGM) microcavities, but cuboid-shape is rarely reported. In this work, we successfully fabricated single crystal cuboid-shaped MAPbBr3 perovskite w让h different morphologies, named microcuboid-MAPbBr3 (M-MAPbBr3) and multi-step-MAPbBr3 (MSMAPbBr3), via solvothermal method. Furthermore, the as-prepared *crystals excitonic recombination lifetime under different pumping energy density was studied by time-resolved photoiuminescence (TRPL). Based on controllable morphology and remarkable lasing properties, these cuboid shaped single crystal perovskite could be a promising candidate for small laser, and other optoelectronic devices.展开更多
Time-resolved photoluminescence(TRPL)has been extensively used to measure the carrier lifetime in lead halide perovskites.The TRPL curves of perovskite materials are usually fitted with a multi-exponential function,in...Time-resolved photoluminescence(TRPL)has been extensively used to measure the carrier lifetime in lead halide perovskites.The TRPL curves of perovskite materials are usually fitted with a multi-exponential function,instead of a single exponential one.This was considered to be a result of the surface and the bulk recombination or the additional radiative recombination caused by the high excited carrier density.Here,a new model considering the diffusion and the trap-assisted recombination of carriers is proposed to explain the TRPL curves.The expressions of the TRPL curves and the transient absorption(TA)dynamic curves are theoretically derived,demonstrating that the TRPL curve is an infinite exponential series,regardless of the presence of surface recombination or not.Our newly developed highly sensitive nanosecond TA and TRPL were employed to measure the carrier dynamics of the same sample under low illumination in the linear response region of TA,thereby experimentally verifying our model.These results suggest that the decay of the TRPL is not only a consequence of the carrier recombination but also the carrier diffusion.TRPL cannot provide a direct measurement of the carrier lifetime,whereas TA spectroscopy can.Furthermore,the surface and the bulk recombination can be resolved and the average diffusion coefficient(D)can also be correctly obtained by combining TRPL and TA measurements.We also propose an approximate method for calculating the carrier lifetime and diffusion coefficient of high-quality perovskite films.Our model provides not only a new interpretation of the dynamics of the PL decay but also a deep insight into the carrier dynamics in the nanosecond time scale under working condition of perovskites solar cells.展开更多
Nanowires require surface passivation due to their inherent large surface to volume ratio. We investigate the effect of embedding InP nanowires in different oxides with respect to surface passivation by use of electro...Nanowires require surface passivation due to their inherent large surface to volume ratio. We investigate the effect of embedding InP nanowires in different oxides with respect to surface passivation by use of electron beam induced current measurements enabled by a nanoprobe based system inside a scanning electron microscope. The measurements reveal remote doping due to fixed charge carriers in the passivating PO_(x)/Al_(2)O_(3) shell in contrast to results using SiO_(x). We used time-resolved photoluminescence to characterize the lifetime of charge carriers to evaluate the success of surface passivation. In addition, spatially resolved internal quantum efficiency simulations support and correlate the two applied techniques. We find that atomic-layer deposited PO_(x)/Al_(2)O_(3) has the potential to passivate the surface of InP nanowires, but at the cost of inducing a field-effect on the nanowires, altering their electrostatic potential profile. The results show the importance of using complementary techniques to correctly evaluate and interpret processing related effects for optimization of nanowire-based optoelectronic devices.展开更多
Currently,enzyme-responsive nanomaterials have shown great promise in prognosis or diagnosis of disease biomarker.However,the great obstacle for conventional enzyme-responsive nanomaterials frequently lies in autofluo...Currently,enzyme-responsive nanomaterials have shown great promise in prognosis or diagnosis of disease biomarker.However,the great obstacle for conventional enzyme-responsive nanomaterials frequently lies in autofluorescence interference,poor monodispersity,uncontrollable size and morphology,low optical stability,and biotoxicity,which fundamentally impede their practical application in biological systems.To overcome these deficiencies,we proposed a novel strategy for reliable and precise detection of an enzyme disease biomarker,alkaline phosphatase(ALP),through lanthanide(Ln^(3+))nucleotide nanoparticles(LNNPs)with extremely improved monodispersity and uniformity,which were achieved by the coordination self-assembly between ATP and Ln^(3+)inside micellar nanoreactor.Specifically,for ATP-Ce/Tb LNNPs,highly improved photoluminescence(PL)emission of Tb^(3+)can be achieved via efficient Ce^(3+)sensitization.We demonstrated that ALP could specifically cleave the phosphorus–oxygen(P–O)bonds of ATP and result in the collapse of ATP-Ce/Tb scaffold,finally leading to the PL quenching of Tb^(3+).By taking advantage of time-resolved(TR)PL technique,the fabricated ATP-Ce/Tb LNNPs presented superior selectivity and sensitivity for the ALP bioassay in complicated serum samples,thus revealing the great potential of ATP-Ce/Tb LNNPs in the areas of ALP-related disease prognosis and diagnosis.展开更多
The Drosophila visual transduction is the fastest known G protein-coupled signaling cascade and has been served as a model for understanding the molecular mechanisms of other G protein-coupled signaling cascades. Numb...The Drosophila visual transduction is the fastest known G protein-coupled signaling cascade and has been served as a model for understanding the molecular mechanisms of other G protein-coupled signaling cascades. Numbers of components in visual transduction machinery have been identified. Based on the functional characterization of these genes, a model for Drosophila phototransduction has been outlined, including rhodopsin activation, phosphoinoside signaling, and the opening of TRP and TRPL channels. Recently, the characterization of mutants, showing slow termination, revealed the physiological significance and the mechanism of rapid termination of light response.展开更多
基金Advanced Research Center for Chemical Building Blocks,ARC CBBC,which is co-foundedco-financed by the Dutch Research Council(NWO)and the Netherlands Ministry of Economic Affairs and Climate Policy.
文摘Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed acetone on three SrTiO_(3)morphologies:cubes(for which exclusively{100}facets are exposed),{110}-truncated cubes,and{100}-truncated rhombic dodecahedrons,respectively,all prepared by hydrothermal synthesis.In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy shows that cubic crystals contain a high quantity of surface-OH groups,enabling significant quantities of adsorbed acetone in the form ofη^(1)-enolate when exposed to gas phase acetone.Contrary,{110}facets exhibit fewer surface-OH groups,resulting in relatively small quantities of adsorbedη^(1)-acetone,without observable quantities of enolate.Interestingly,acetate and formate signatures appear in the spectra of cubic,surfaceη^(1)-enolate containing,SrTiO_(3)upon illumination,while besides acetate and formate,the formation of(surface)formaldehyde was observed on truncated cubes,and dodecahedrons,by conversion of adsorbedη^(1)-acetone.Time-Resolved Photoluminescence studies demonstrate that the lifetimes of photogenerated charge carriers vary with crystal morphology.The shortest carrier lifetime(τ_(1)=33±0.1 ps)was observed in{110}-truncated cube SrTiO_(3),likely due to a relatively strong built-in electric field promoting electron transport to{100}facets and hole transport to{110}facets.The second lifetime(τ_(2)=259±1 ps)was also the shortest for this morphology,possibly due to a higher amount of surface trap states.Our results demonstrate that SrTiO_(3)crystal morphology can be tuned to optimize performance in photocatalytic oxidation.
文摘Luminescence decay and time resolved photoluminescence(TRPL) spectra are used for study on the transient luminescence process of the nominally disordered GaInP alloy. The luminescence decay of GaInP alloy shows the temperature and excitation intensity dependent characters. At 77 K and under high excitation intensity, the luminescence decay shows single exponential time dependence, while under low excitation intensity or at 300 K, the luminescence decay shows double exponential time dependence. The analysis indicates that this nominally disordered GaInP alloy actually exhibits a very weak degree of order. The blue shift of PL peak is observed in the TRPL spectra at 77 K, which is derived from the transfer of the carriers from the ordered domain to the disordered region of the alloy. At 300 K, due to the thermal quenching, the transfer is too weak to be observed. However, The recombination of the carriers between the ordered domain and the disordered region is still devoted to luminesce.
基金supported by the National Natural Science Foundation of China(11674023,51331002,51622205,61675027,61505010,51502018,51525202 and 51432005)111 Project(B170003)+2 种基金the National Key Research and Development Program of China(2016YFA0202703)Beijing Natural Science Foundation(4181004 and 4182080)the ‘‘Thousand Talents” Program of China for Pioneering Researchers and Innovative Teams(U1404619)
文摘As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. The perovskite materials with ID and 2D shapes were widely prepared and studied for Fabry-Perot mode and whispering-gallery-mode (WGM) microcavities, but cuboid-shape is rarely reported. In this work, we successfully fabricated single crystal cuboid-shaped MAPbBr3 perovskite w让h different morphologies, named microcuboid-MAPbBr3 (M-MAPbBr3) and multi-step-MAPbBr3 (MSMAPbBr3), via solvothermal method. Furthermore, the as-prepared *crystals excitonic recombination lifetime under different pumping energy density was studied by time-resolved photoiuminescence (TRPL). Based on controllable morphology and remarkable lasing properties, these cuboid shaped single crystal perovskite could be a promising candidate for small laser, and other optoelectronic devices.
基金supported by the National Natural Science Foundation of China(Grant No.11888101)National Key Research and Development Program of China(Grant No.2022YFA1403901)+1 种基金Sichuan Science and Technology Program(Grant Nos.2021JDTD0021,and 2022ZYD0015)Innovation Funds from China Academy of Engineering Physics(Grant No.CX20210037)。
文摘Time-resolved photoluminescence(TRPL)has been extensively used to measure the carrier lifetime in lead halide perovskites.The TRPL curves of perovskite materials are usually fitted with a multi-exponential function,instead of a single exponential one.This was considered to be a result of the surface and the bulk recombination or the additional radiative recombination caused by the high excited carrier density.Here,a new model considering the diffusion and the trap-assisted recombination of carriers is proposed to explain the TRPL curves.The expressions of the TRPL curves and the transient absorption(TA)dynamic curves are theoretically derived,demonstrating that the TRPL curve is an infinite exponential series,regardless of the presence of surface recombination or not.Our newly developed highly sensitive nanosecond TA and TRPL were employed to measure the carrier dynamics of the same sample under low illumination in the linear response region of TA,thereby experimentally verifying our model.These results suggest that the decay of the TRPL is not only a consequence of the carrier recombination but also the carrier diffusion.TRPL cannot provide a direct measurement of the carrier lifetime,whereas TA spectroscopy can.Furthermore,the surface and the bulk recombination can be resolved and the average diffusion coefficient(D)can also be correctly obtained by combining TRPL and TA measurements.We also propose an approximate method for calculating the carrier lifetime and diffusion coefficient of high-quality perovskite films.Our model provides not only a new interpretation of the dynamics of the PL decay but also a deep insight into the carrier dynamics in the nanosecond time scale under working condition of perovskites solar cells.
文摘Nanowires require surface passivation due to their inherent large surface to volume ratio. We investigate the effect of embedding InP nanowires in different oxides with respect to surface passivation by use of electron beam induced current measurements enabled by a nanoprobe based system inside a scanning electron microscope. The measurements reveal remote doping due to fixed charge carriers in the passivating PO_(x)/Al_(2)O_(3) shell in contrast to results using SiO_(x). We used time-resolved photoluminescence to characterize the lifetime of charge carriers to evaluate the success of surface passivation. In addition, spatially resolved internal quantum efficiency simulations support and correlate the two applied techniques. We find that atomic-layer deposited PO_(x)/Al_(2)O_(3) has the potential to passivate the surface of InP nanowires, but at the cost of inducing a field-effect on the nanowires, altering their electrostatic potential profile. The results show the importance of using complementary techniques to correctly evaluate and interpret processing related effects for optimization of nanowire-based optoelectronic devices.
基金supported by the National Key R&D Program of China(No.2022YFB3503700)the National Natural Science Foundation of China(NSFC)(Nos.22135008,U22A20398,and 22275190)+1 种基金the Natural Science Foundation of Fujian Province(Nos.2021L3024,2021Y0067)the Open Fund of State Key Laboratory of Structural Chemistry(No.20210023).
文摘Currently,enzyme-responsive nanomaterials have shown great promise in prognosis or diagnosis of disease biomarker.However,the great obstacle for conventional enzyme-responsive nanomaterials frequently lies in autofluorescence interference,poor monodispersity,uncontrollable size and morphology,low optical stability,and biotoxicity,which fundamentally impede their practical application in biological systems.To overcome these deficiencies,we proposed a novel strategy for reliable and precise detection of an enzyme disease biomarker,alkaline phosphatase(ALP),through lanthanide(Ln^(3+))nucleotide nanoparticles(LNNPs)with extremely improved monodispersity and uniformity,which were achieved by the coordination self-assembly between ATP and Ln^(3+)inside micellar nanoreactor.Specifically,for ATP-Ce/Tb LNNPs,highly improved photoluminescence(PL)emission of Tb^(3+)can be achieved via efficient Ce^(3+)sensitization.We demonstrated that ALP could specifically cleave the phosphorus–oxygen(P–O)bonds of ATP and result in the collapse of ATP-Ce/Tb scaffold,finally leading to the PL quenching of Tb^(3+).By taking advantage of time-resolved(TR)PL technique,the fabricated ATP-Ce/Tb LNNPs presented superior selectivity and sensitivity for the ALP bioassay in complicated serum samples,thus revealing the great potential of ATP-Ce/Tb LNNPs in the areas of ALP-related disease prognosis and diagnosis.
基金supported by National Natural Science Foundation of China (Grant Nos. 30970663 and 31070683)New-Century Training Program Foundation for the Talents by the State Education CommissionYouth Foundation of Southeast University to J. H.
文摘The Drosophila visual transduction is the fastest known G protein-coupled signaling cascade and has been served as a model for understanding the molecular mechanisms of other G protein-coupled signaling cascades. Numbers of components in visual transduction machinery have been identified. Based on the functional characterization of these genes, a model for Drosophila phototransduction has been outlined, including rhodopsin activation, phosphoinoside signaling, and the opening of TRP and TRPL channels. Recently, the characterization of mutants, showing slow termination, revealed the physiological significance and the mechanism of rapid termination of light response.
