All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have attracted extensive attention in photoelectric detection for their excellent photoelectric properties and stability.However,the CsPbBr_(3) quantum dot film exh...All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have attracted extensive attention in photoelectric detection for their excellent photoelectric properties and stability.However,the CsPbBr_(3) quantum dot film exhibits a high non-radiative recombination rate,and the mismatch in energy levels with the carbon electrode weakens hole extraction efficiency.These reduces the device's performance.To improve this,a semiconductor photodetector based on fluorine-doped tin oxide(FTO)/dense titanium dioxide(c-TiO_(2))/mesoporous titanium dioxide(m-TiO_(2))/CsPbBr_(3) QDs/CsPbBr_(x)I_(3-x)(x=2,1.5,1)QDs/C struc-ture was studied.By adjusting the Br-:I-ratio,the synthesized CsPbBr_(x)I_(3-x)(x=2,1.5,1)QDs showed an adjustable band gap width of 2.284-2.394 eV.And forming a typeⅡband structure with CsPbBr_(3) QDs,which reduced the valence band offset between the active layer and the carbon electrode,this promoted carrier extraction and reduced non-radiative recombination rate.Compared with the original device(the photosensitive layer is CsPbBr_(3) QDs),the performance of the photodetector based on the CsPbBr_(3) QDs/CsPbBr2I QDs heterostructure is significantly improved,the responsivity(R)increased by 73%,the specific detectivity rate(D^(*))increased from 6.98×10^(12) to 3.19×10^(13) Jones,the on/off ratio reached 106.This study provides a new idea for the development of semiconductor tandem detectors.展开更多
The generation and manipulation of spin-polarized electrons at room temperature are essential for the development of advanced spin-optoelectronic devices.In this work,a one-pot method was used to successfully synthesi...The generation and manipulation of spin-polarized electrons at room temperature are essential for the development of advanced spin-optoelectronic devices.In this work,a one-pot method was used to successfully synthesize homogenous Mn:CsPbBr_(3) perovskite quantum dots in air with particle sizes of 7−8 nm.The effects of Mn doping on the structure,optical and magnetic properties of CsPbBr_(3) quantum dots were investigated.The findings demonstrated proper Mn doping improved the crystallinity and photoluminescence(PL)of quantum dots.The prepared quantum dots have a narrow full width at half maximum emission(FWHM)of about 17−20 nm.The magnetic properties of the doped samples and the effect of the magnetic field on the PL spectra properties were analyzed.The results show that trace Mn doping can improve the room-temperature ferromagnetism of CsPbBr_(3) quantum dots.Doping with magnetic elements makes CsPbBr_(3) quantum dots more responsive to the applied magnetic field.Even at a lower 50 mT magnetic field,the PL peak of Mn:CsPbBr_(3) still declined 5.91%.Mn:CsPbBr_(3) quantum dots are a new type of multifunctional material that is beneficial to spintronics research.This work demonstrates a low-cost synthesis method.It should make all-inorganic perovskite quantum dots a promising material for room-temperature spin optoelectronic devices.展开更多
In this study,egg white peptides(EWP)were prepared using preheat treatment combined with a bienzymatic hydrolysis.Results on peptide yield and molecular weight distribution showed that preheat treatment could obviousl...In this study,egg white peptides(EWP)were prepared using preheat treatment combined with a bienzymatic hydrolysis.Results on peptide yield and molecular weight distribution showed that preheat treatment could obviously promote egg white hydrolysis.The yield of EWP obtained from neutral-alkaline protease treatment was 74.62%±0.23%and 92.69%of EWP was between 200 Da and 500 Da.Supplementation with 750 mg/kg/d EWP significantly alleviated the decrease of immune organ index in immunosuppressed male BLAB/c mice caused by cyclophosphamide.The pathological changes of spleen showed that EWP could also alleviate the damage of spleen tissue.The number of white blood cells in peripheral blood and the levels of serum cytokines(IL-6,IL-2 and TNF-α)in 750 mg/kg/d EWP group were significantly higher than the model group.The immunomodulatory effects of EWP might be related to the presence of abundant branched-chain amino acids,which were important components of immunomodulatory peptides.Eight possible immunomodulatory peptides were identified from EWP by High Performance Liquid Chromatography-Mass Spectrometry in combination with ProteinLynx Global SERVER and mass spectral database.Therefore,EWP may have potential as a natural immunomodulator for the prevention of immune damage caused by external influences.展开更多
文摘All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have attracted extensive attention in photoelectric detection for their excellent photoelectric properties and stability.However,the CsPbBr_(3) quantum dot film exhibits a high non-radiative recombination rate,and the mismatch in energy levels with the carbon electrode weakens hole extraction efficiency.These reduces the device's performance.To improve this,a semiconductor photodetector based on fluorine-doped tin oxide(FTO)/dense titanium dioxide(c-TiO_(2))/mesoporous titanium dioxide(m-TiO_(2))/CsPbBr_(3) QDs/CsPbBr_(x)I_(3-x)(x=2,1.5,1)QDs/C struc-ture was studied.By adjusting the Br-:I-ratio,the synthesized CsPbBr_(x)I_(3-x)(x=2,1.5,1)QDs showed an adjustable band gap width of 2.284-2.394 eV.And forming a typeⅡband structure with CsPbBr_(3) QDs,which reduced the valence band offset between the active layer and the carbon electrode,this promoted carrier extraction and reduced non-radiative recombination rate.Compared with the original device(the photosensitive layer is CsPbBr_(3) QDs),the performance of the photodetector based on the CsPbBr_(3) QDs/CsPbBr2I QDs heterostructure is significantly improved,the responsivity(R)increased by 73%,the specific detectivity rate(D^(*))increased from 6.98×10^(12) to 3.19×10^(13) Jones,the on/off ratio reached 106.This study provides a new idea for the development of semiconductor tandem detectors.
基金supported by the Hubei province Natural Science Fund for Distinguished Young Scholars(No.201CFA077)Hubei province“Chu Tian Talent”scientific and technological innovation team.
文摘The generation and manipulation of spin-polarized electrons at room temperature are essential for the development of advanced spin-optoelectronic devices.In this work,a one-pot method was used to successfully synthesize homogenous Mn:CsPbBr_(3) perovskite quantum dots in air with particle sizes of 7−8 nm.The effects of Mn doping on the structure,optical and magnetic properties of CsPbBr_(3) quantum dots were investigated.The findings demonstrated proper Mn doping improved the crystallinity and photoluminescence(PL)of quantum dots.The prepared quantum dots have a narrow full width at half maximum emission(FWHM)of about 17−20 nm.The magnetic properties of the doped samples and the effect of the magnetic field on the PL spectra properties were analyzed.The results show that trace Mn doping can improve the room-temperature ferromagnetism of CsPbBr_(3) quantum dots.Doping with magnetic elements makes CsPbBr_(3) quantum dots more responsive to the applied magnetic field.Even at a lower 50 mT magnetic field,the PL peak of Mn:CsPbBr_(3) still declined 5.91%.Mn:CsPbBr_(3) quantum dots are a new type of multifunctional material that is beneficial to spintronics research.This work demonstrates a low-cost synthesis method.It should make all-inorganic perovskite quantum dots a promising material for room-temperature spin optoelectronic devices.
基金supported by the National Natural Science Foundation for the Youth of China(No.31901642).
文摘In this study,egg white peptides(EWP)were prepared using preheat treatment combined with a bienzymatic hydrolysis.Results on peptide yield and molecular weight distribution showed that preheat treatment could obviously promote egg white hydrolysis.The yield of EWP obtained from neutral-alkaline protease treatment was 74.62%±0.23%and 92.69%of EWP was between 200 Da and 500 Da.Supplementation with 750 mg/kg/d EWP significantly alleviated the decrease of immune organ index in immunosuppressed male BLAB/c mice caused by cyclophosphamide.The pathological changes of spleen showed that EWP could also alleviate the damage of spleen tissue.The number of white blood cells in peripheral blood and the levels of serum cytokines(IL-6,IL-2 and TNF-α)in 750 mg/kg/d EWP group were significantly higher than the model group.The immunomodulatory effects of EWP might be related to the presence of abundant branched-chain amino acids,which were important components of immunomodulatory peptides.Eight possible immunomodulatory peptides were identified from EWP by High Performance Liquid Chromatography-Mass Spectrometry in combination with ProteinLynx Global SERVER and mass spectral database.Therefore,EWP may have potential as a natural immunomodulator for the prevention of immune damage caused by external influences.
