Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by hig...Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.展开更多
The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic...The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic rate of cherry leaves under weak light was remarkably lower; the activity peroxidase (POD) increased when light intensity decreased; the activity of catalase (CAT) showed an opposite trend, and it was positively correlated with light intensity; the activity of superoxide dismutase (SOD) increased under 366 μmol·m -2 ·s -1 and 533.8 μmol·m -2 ·s -1 light intensity, but decreased under 228.8 μmol·m -2 ·s -1 and 83.9 μmol·m -2 ·s -1 light intensity. A remarkable increase of malondialdehyde (MDA), a product of membrane_lipid peroxidation, was also observed in cherry leaves when treated with weak light, indicating more serious peroxidation in the membrane.展开更多
Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural charact...Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural characteristics of phloem tissues of source leaves were observed and compared in normal and weak light intensities using the transmission electron microscopy. Results showed that the average diameters of companion cells (CC) and sieve elements (SE) of all kinds of veins were bigger in normal than that in weak light intensity, indicating that light could influence the cell development and growth. Dense cytoplasm with abundant mitochondria, endoplasmic reticulums, multivesicular bodies, vesicles and plastids were observed in normal light intensity. On the contrary, CC with small vacuolar structures and few mitochondrias, endoplasmic reticulums were shown in weak light. Misalignment of grana thylakoid margins of nectarine leaves also was seen in weak light. The sieve pores of SEs were obstructed in weak light. Chloroplasts with numerous starch grains and few mitochondrias were noticed in the mesophyll cell (MES) surrounding the bundle sheath in weak light. The storage of starch grains appeared to result from an unbalance between photosynthate production and export of photosynthates. This observation provided a strong support to the point that most leaves export the most of assimilates in the light time. Plasmodesmal densities between SE/CC, CC/PP (phloem parenchyma cell), PP/PP and PP/BSC (bundle_sheath cell) decreased in weak light. Plasmodesmata were observed between CC/SE (NS) (nacreous_walled sieve element), PP/BSC in branch veins in normal light intensity, but not in weak light. Thus apoplasmic pathway may be the main mode of transport of assimilates in weak light, however symplasmic pathway may be the main mode of transport of assimilates in normal light intensity. These results demonstrated that the solar greenhouse nectarine trees could be adapted to the weak light via the ultrastructure variation of phloem tissues of the source leaves.展开更多
Dynamic changes of starch, amylose, sucrose contents and the activities of starch synthesis enzymes under shading treatments alter flowering were studied using two rice varieties IR72 （indica） and Nipponbare （japon...Dynamic changes of starch, amylose, sucrose contents and the activities of starch synthesis enzymes under shading treatments alter flowering were studied using two rice varieties IR72 （indica） and Nipponbare （japonica） as materials. Under shading treatments, the starch, amylose and sucrose contents decreased, while ADP-glucose pyrophosphorylase （ADPGPPase） activity only changed a little, soluble starch synthase activity and granule bound starch synthase activity decreased, soluble starch branching enzyme （SSBE, Q-enzyme） activity and granule bound starch branching enzyme （GBSBE, Q-enzyme） activity increased, and starch debranching enzyme （DBE, R-enzyme） activity varied with varieties. Correlation analyses showed that the changes of starch content were positively and significantly correlated with the changes of sucrose content in the weak light. Both ADPGPPase activity and SSBE activity were positively and significantly correlated with starch accumulation rate. It was implied that the decline of starch synthase activities was related to the decrease of starch content and the increase of the activity of starch branching enzyme played an important role in the decrease of the ratio of amylose to the total starch under the weak light.展开更多
Anthocyanidin in plants, an important pigment, is of great interest to researchers, consumers, and commercial entities due to its physiological functions. Anthocyanin content and mRNA levels of anthocynin biosynthesis...Anthocyanidin in plants, an important pigment, is of great interest to researchers, consumers, and commercial entities due to its physiological functions. Anthocyanin content and mRNA levels of anthocynin biosynthesis genes were investigated in storage root of different purple-fleshed sweet potatoes (PFSP) genotypes to understand the regulation mechanism of anthocyanin under weak light conditions. Anthocyanin content, its amount of accumulation, and the expression of CHS, DFR, F3H, GT, and ANS genes in the PFSP storage root under weak light conditions were studied. The results demonstrated that the anthocyanin content of the treatments was decreased and was obviously lower than that of the control until 30 days after shading in Ayamurasaki, while it was lower than that of the control from the beginning of shading in Jishu 18. Their accumulation rates of both treatmeants were lower than its control before 10-20 d of shading in Jishu 18, while those of Ayamurasaki weren't in their treatments. This indicated that Jishul 8 is more sensitive to light as compared to Ayamuraska. Under the different weak light conditions, mRNA levels for ibCHS, ibF3H, ibDFR, and ibANS were obviously decreased, while the expression of ibGT was increased. These results indicated that anthocyanin content was regulated by light at the mRNA levels and the enzymatic level in sweet potato. Therefore, the development dynamic response to anthocyanin content varied in different genotypes of PFSP, and mRNA levels of anthocyanin biosynthesis were inhibited under the weak light condition.展开更多
The effect of weak light on the photoassimilates distribution and transformation of young Jingyu grape plants ( Vitis vinefera L. cv. Jingyu) were studied by shading. Compared to the grape grown under natural light in...The effect of weak light on the photoassimilates distribution and transformation of young Jingyu grape plants ( Vitis vinefera L. cv. Jingyu) were studied by shading. Compared to the grape grown under natural light intensity environment, the net photosynthetic rate diurnal variation curve of experimental plants grown in weak light intensity environment was remarkably lower. Its leaf and stem biomass ratio increased when light intensity decreased, the root and new shoot biomass ratio showed an opposite trend. The 14 C-photoassimilates was mostly distributed to young leaves and stem, a little was distributed to root. The metabolism of 14C-photoassimilates distributed to the entire grape body were also changed under weak light intensity environment.展开更多
Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribu...Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribution along with multiple reconstruction methods for super-resolution imaging.The proposed technology reduces the point-spread function of an imag-ing system through single-neutron detection and event reconstruction,thereby significantly improving imaging resolution.A single-neutron detection experiment was conducted using a highly practical and efficient^(6)LiF-ZnS scintillation screen of a cold neutron imaging device in the research reactor.In milliseconds of exposure time,a large number of weak light clusters and their distribution in the scintillation screen were recorded frame by frame,to complete single-neutron detection.Several reconstruction algorithms were proposed for the calculations.The location of neutron capture was calculated using several processing methods such as noise removal,filtering,spot segmentation,contour analysis,and local positioning.The proposed algorithm achieved a higher imaging resolution and faster reconstruction speed,and single-neutron super-resolution imaging was realized by combining single-neutron detection experiments and reconstruction calculations.The results show that the resolution of the 100μm thick^(6)LiF-ZnS scintillation screen can be improved from 125 to 40 microns.This indicates that the proposed single-neutron detection and calculation method is effective and can significantly improve imaging resolution.展开更多
In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to t...In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to this problem. Here in this study, a novel organic phototransistor based on a high mobility n-type small molecule as the conducting layer and an isolated bulk heterojunction light-absorbing layer as the floating gate has been demonstrated in this study. With the special designed device structure, the phototransistor shows extremely high sensitivity to broad spectral and weak light irradiation, and the photoresponsivity and photocurrent/dark-current ratio of the device can reach up to 4840 mA/W and 1.8×10~5 respectively.For conclusion, this study suggests a potential way to obtain high-performance phototransistors at room temperature, which will further promote the commercial application of organic phototransistors.展开更多
Potted seedlings of Hedera nepalensis and H. helix were exposed to formaldehyde and low light alone or in combination for four months, before the morphological and nutritive indices of the plants were measured to asse...Potted seedlings of Hedera nepalensis and H. helix were exposed to formaldehyde and low light alone or in combination for four months, before the morphological and nutritive indices of the plants were measured to assess the effects of formaldehyde and low-light stress on the growth and nutrient accumulation of Hedera species. The results showed that treatment with either formaldehyde or low-light stress reduced leaf length, leaf width, stem length, stem diameter, root length and biomass, but increased leaf shape index of the two Hedera species. Treatment with formaldehyde alone increased root-shoot ratio, while treatment with formaldehyde ＋ low light or low light alone decreased root-shoot ratio of the two Hedera species. Under the stress of formaldehyde, soluble sugar content decreased, while starch content increased in roots, stems and leaves of the two Hedera species; total carbon content, proline content and carbon-to-nitrogen （C/N） ratio increased, while protein content and phosphorus content decreased in roots of the two Hedera species; the contents of total carbon, protein and total nitrogen in leaves of the two Hedera species; C/N ratio in roots of H. nepalensis increased; the C/N ratio in roots of H. nepalensis and that in leaves of the two Hedera species significantly increased. Under formaldehyde ＋ low light stress, the soluble sugar content decreased, while starch content increased in stems and leaves of the two Hedera species; starch content in roots of the two Hedera species decreased; the contents of protein and total nitrogen decreased, while C/N ratio increased in leaves of H. nepalensis ; proline content in roots and stems of the two Hedera species significantly increased.展开更多
Weak light imaging has drawn more and more attention because of its promising potential for practical applications in security monitoring and space exploration. In this work, all-inorganic Cs2AgBiBr6 double perovskite...Weak light imaging has drawn more and more attention because of its promising potential for practical applications in security monitoring and space exploration. In this work, all-inorganic Cs2AgBiBr6 double perovskite-based self-powered photodetectors containing inorganic copper thiocyanate(CuSCN) as hole-transport layers(HTLs) are successfully fabricated and applied for weak light imaging,which is the first report on the weak light imaging application of all-inorganic lead-free perovskite photodetectors. CuSCN films with favorable optical property and hole extraction capability are prepared via a cost efficient and fast solvent removal method, demonstrating the potential for high-performance perovskite-based devices as transparent components. It is revealed that the band alignment of the device is effectively optimized with the presence of CuSCN HTLs,which can availably transport holes while block electrons at the Cs2AgBiBr6/CuSCN interface, resulting in remarkable improvement of photoresponse performance. The responsivity and detectivity are 0.34 A W^-1 and 1.03×10^13 Jones,respectively. In particular, the light current has a boost of almost 10 times. Furthermore, the photodetectors are integrated into a self-built light detection imaging system utilizing the focused laser scanning imaging mode. With illumination of as low as 5 nW cm^-2(405 nm), the image involving graphics and words with a size of 5 cm×5 cm can still be distinctly recognized. These results suggest the promising potential of all-inorganic perovskite-based devices for weak light detection and imaging applications.展开更多
Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-...Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-processed thermodynamic or kinetic growth of high-quality narrow bandgap kesterite CZTSSe thin film is developed.A self-powered CZTSSe/CdS thin-film PD is then successfully fabricated.Under optimization of light absorber and heterojunction interface,especially tailoring the defect and carrier kinetics,it can achieve broadband response from300 to 1300 nm,accompaniedwith a high responsivity of 1.37A/W,specific detectivity(D*)up to 4.0×10^(14)Jones under 5 nW/cm^(2),a linear dynamic range(LDR)of 126 dB,and a maximum Ilight/Idark ratio of 1.3×10^(8)within the LDR,and ultrafast response speed(rise/decay time of 16 ns/85 ns),representing the leading-level performance to date,which is superior to those of commercial andwell-researched photodiodes.Additionally,an imaging system with a 905nm laser is built for weak light response evaluation,and can respond to 718 pW weak light and infrared imaging at a wavelength as low as 5 nW/cm2.It has also been employed for photoplethysmography detection of pulsating signals at both the finger and wrist,presenting obvious arterial blood volume changes,demonstrating great application potential in broadband and weak light photodetection scenarios.展开更多
We propose ghost imaging(GI)with deep learning to improve detection speed.GI,which uses an illumination light with random patterns and a single-pixel detector,is correlation-based and thus suitable for detecting weak ...We propose ghost imaging(GI)with deep learning to improve detection speed.GI,which uses an illumination light with random patterns and a single-pixel detector,is correlation-based and thus suitable for detecting weak light.However,its detection time is too long for practical inspection.To overcome this problem,we applied a convolutional neural network that was constructed based on a classification of the causes of ghost image degradation.A feasibility experiment showed that when using a digital mirror device projector and a photodiode,the proposed method improved the quality of ghost images.展开更多
Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential t...Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.展开更多
基金supported by the National Natural Science Foundation of China(No.52472225)the Science and Technology Plan Project of Shenzhen(No.20220808165025003),China。
文摘Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.
文摘The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic rate of cherry leaves under weak light was remarkably lower; the activity peroxidase (POD) increased when light intensity decreased; the activity of catalase (CAT) showed an opposite trend, and it was positively correlated with light intensity; the activity of superoxide dismutase (SOD) increased under 366 μmol·m -2 ·s -1 and 533.8 μmol·m -2 ·s -1 light intensity, but decreased under 228.8 μmol·m -2 ·s -1 and 83.9 μmol·m -2 ·s -1 light intensity. A remarkable increase of malondialdehyde (MDA), a product of membrane_lipid peroxidation, was also observed in cherry leaves when treated with weak light, indicating more serious peroxidation in the membrane.
文摘Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural characteristics of phloem tissues of source leaves were observed and compared in normal and weak light intensities using the transmission electron microscopy. Results showed that the average diameters of companion cells (CC) and sieve elements (SE) of all kinds of veins were bigger in normal than that in weak light intensity, indicating that light could influence the cell development and growth. Dense cytoplasm with abundant mitochondria, endoplasmic reticulums, multivesicular bodies, vesicles and plastids were observed in normal light intensity. On the contrary, CC with small vacuolar structures and few mitochondrias, endoplasmic reticulums were shown in weak light. Misalignment of grana thylakoid margins of nectarine leaves also was seen in weak light. The sieve pores of SEs were obstructed in weak light. Chloroplasts with numerous starch grains and few mitochondrias were noticed in the mesophyll cell (MES) surrounding the bundle sheath in weak light. The storage of starch grains appeared to result from an unbalance between photosynthate production and export of photosynthates. This observation provided a strong support to the point that most leaves export the most of assimilates in the light time. Plasmodesmal densities between SE/CC, CC/PP (phloem parenchyma cell), PP/PP and PP/BSC (bundle_sheath cell) decreased in weak light. Plasmodesmata were observed between CC/SE (NS) (nacreous_walled sieve element), PP/BSC in branch veins in normal light intensity, but not in weak light. Thus apoplasmic pathway may be the main mode of transport of assimilates in weak light, however symplasmic pathway may be the main mode of transport of assimilates in normal light intensity. These results demonstrated that the solar greenhouse nectarine trees could be adapted to the weak light via the ultrastructure variation of phloem tissues of the source leaves.
文摘Dynamic changes of starch, amylose, sucrose contents and the activities of starch synthesis enzymes under shading treatments alter flowering were studied using two rice varieties IR72 （indica） and Nipponbare （japonica） as materials. Under shading treatments, the starch, amylose and sucrose contents decreased, while ADP-glucose pyrophosphorylase （ADPGPPase） activity only changed a little, soluble starch synthase activity and granule bound starch synthase activity decreased, soluble starch branching enzyme （SSBE, Q-enzyme） activity and granule bound starch branching enzyme （GBSBE, Q-enzyme） activity increased, and starch debranching enzyme （DBE, R-enzyme） activity varied with varieties. Correlation analyses showed that the changes of starch content were positively and significantly correlated with the changes of sucrose content in the weak light. Both ADPGPPase activity and SSBE activity were positively and significantly correlated with starch accumulation rate. It was implied that the decline of starch synthase activities was related to the decrease of starch content and the increase of the activity of starch branching enzyme played an important role in the decrease of the ratio of amylose to the total starch under the weak light.
基金support by the NationalHigh-Tech R&D Program of China (863 Program,2006AA100107)the National Key Technologies R&DProgram of China (2006BAD01A06-2)+2 种基金the NationalSpecial Scientific Research Project for Public Industryof China (nyhyzx07-012-03)the Project of 948 from Ministry of Agriculture of China (2006-G21-02)the National System of Sweet Potato Industrial Tech-nology of China (nycytx-16-B-3)
文摘Anthocyanidin in plants, an important pigment, is of great interest to researchers, consumers, and commercial entities due to its physiological functions. Anthocyanin content and mRNA levels of anthocynin biosynthesis genes were investigated in storage root of different purple-fleshed sweet potatoes (PFSP) genotypes to understand the regulation mechanism of anthocyanin under weak light conditions. Anthocyanin content, its amount of accumulation, and the expression of CHS, DFR, F3H, GT, and ANS genes in the PFSP storage root under weak light conditions were studied. The results demonstrated that the anthocyanin content of the treatments was decreased and was obviously lower than that of the control until 30 days after shading in Ayamurasaki, while it was lower than that of the control from the beginning of shading in Jishu 18. Their accumulation rates of both treatmeants were lower than its control before 10-20 d of shading in Jishu 18, while those of Ayamurasaki weren't in their treatments. This indicated that Jishul 8 is more sensitive to light as compared to Ayamuraska. Under the different weak light conditions, mRNA levels for ibCHS, ibF3H, ibDFR, and ibANS were obviously decreased, while the expression of ibGT was increased. These results indicated that anthocyanin content was regulated by light at the mRNA levels and the enzymatic level in sweet potato. Therefore, the development dynamic response to anthocyanin content varied in different genotypes of PFSP, and mRNA levels of anthocyanin biosynthesis were inhibited under the weak light condition.
基金supported by the National Natural Science Foundation of China(30070531).
文摘The effect of weak light on the photoassimilates distribution and transformation of young Jingyu grape plants ( Vitis vinefera L. cv. Jingyu) were studied by shading. Compared to the grape grown under natural light intensity environment, the net photosynthetic rate diurnal variation curve of experimental plants grown in weak light intensity environment was remarkably lower. Its leaf and stem biomass ratio increased when light intensity decreased, the root and new shoot biomass ratio showed an opposite trend. The 14 C-photoassimilates was mostly distributed to young leaves and stem, a little was distributed to root. The metabolism of 14C-photoassimilates distributed to the entire grape body were also changed under weak light intensity environment.
基金supported by the National Natural Science Foundation of China(Nos.12205271,12075217,U20B2011,and 51978218)Sichuan Science and Technology Program(No.2019ZDZX0010)the National Key R&D Program of China(No.2022YFA1604002).
文摘Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribution along with multiple reconstruction methods for super-resolution imaging.The proposed technology reduces the point-spread function of an imag-ing system through single-neutron detection and event reconstruction,thereby significantly improving imaging resolution.A single-neutron detection experiment was conducted using a highly practical and efficient^(6)LiF-ZnS scintillation screen of a cold neutron imaging device in the research reactor.In milliseconds of exposure time,a large number of weak light clusters and their distribution in the scintillation screen were recorded frame by frame,to complete single-neutron detection.Several reconstruction algorithms were proposed for the calculations.The location of neutron capture was calculated using several processing methods such as noise removal,filtering,spot segmentation,contour analysis,and local positioning.The proposed algorithm achieved a higher imaging resolution and faster reconstruction speed,and single-neutron super-resolution imaging was realized by combining single-neutron detection experiments and reconstruction calculations.The results show that the resolution of the 100μm thick^(6)LiF-ZnS scintillation screen can be improved from 125 to 40 microns.This indicates that the proposed single-neutron detection and calculation method is effective and can significantly improve imaging resolution.
基金supported financially by the Ministry of Science and Technology of the People's Republic of China(No.2017YFA0206600)the National Natural Science Foundation of China(Nos.52050171,51822301,22175047,52103203,and 91963126)+4 种基金the CAS Instrument Development Project(No.YJKYYQ20170037)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36020000)the CAS Pioneer Hundred Talents Programthe Natural Science Foundation of Shandong Province(No.ZR2020ME070)China Postdoctoral Science Foundation(No.2021M690802)。
文摘In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to this problem. Here in this study, a novel organic phototransistor based on a high mobility n-type small molecule as the conducting layer and an isolated bulk heterojunction light-absorbing layer as the floating gate has been demonstrated in this study. With the special designed device structure, the phototransistor shows extremely high sensitivity to broad spectral and weak light irradiation, and the photoresponsivity and photocurrent/dark-current ratio of the device can reach up to 4840 mA/W and 1.8×10~5 respectively.For conclusion, this study suggests a potential way to obtain high-performance phototransistors at room temperature, which will further promote the commercial application of organic phototransistors.
基金Supported by Applied Basic Research Program of Yunnan Province(2017FD087)National Natural Science Foundation of China(31660559)
文摘Potted seedlings of Hedera nepalensis and H. helix were exposed to formaldehyde and low light alone or in combination for four months, before the morphological and nutritive indices of the plants were measured to assess the effects of formaldehyde and low-light stress on the growth and nutrient accumulation of Hedera species. The results showed that treatment with either formaldehyde or low-light stress reduced leaf length, leaf width, stem length, stem diameter, root length and biomass, but increased leaf shape index of the two Hedera species. Treatment with formaldehyde alone increased root-shoot ratio, while treatment with formaldehyde ＋ low light or low light alone decreased root-shoot ratio of the two Hedera species. Under the stress of formaldehyde, soluble sugar content decreased, while starch content increased in roots, stems and leaves of the two Hedera species; total carbon content, proline content and carbon-to-nitrogen （C/N） ratio increased, while protein content and phosphorus content decreased in roots of the two Hedera species; the contents of total carbon, protein and total nitrogen in leaves of the two Hedera species; C/N ratio in roots of H. nepalensis increased; the C/N ratio in roots of H. nepalensis and that in leaves of the two Hedera species significantly increased. Under formaldehyde ＋ low light stress, the soluble sugar content decreased, while starch content increased in stems and leaves of the two Hedera species; starch content in roots of the two Hedera species decreased; the contents of protein and total nitrogen decreased, while C/N ratio increased in leaves of H. nepalensis ; proline content in roots and stems of the two Hedera species significantly increased.
基金supported by the National Natural Science Foundation of China (51772135)the Ministry of Education of China (6141A02022516)+4 种基金the Fundamental Research Funds for the Central Universities (11619103)China Postdoctoral Science Foundation (2019M663376)Guangdong Province Higher Vocational Colleges & Schools Pearl River Scholar Funded Scheme (2017)the Natural Science Foundation of Guangdong Province, China (2017A020215135 and 2018A030310659)the Science and Technology Program of Guangzhou, China (201804010432)。
文摘Weak light imaging has drawn more and more attention because of its promising potential for practical applications in security monitoring and space exploration. In this work, all-inorganic Cs2AgBiBr6 double perovskite-based self-powered photodetectors containing inorganic copper thiocyanate(CuSCN) as hole-transport layers(HTLs) are successfully fabricated and applied for weak light imaging,which is the first report on the weak light imaging application of all-inorganic lead-free perovskite photodetectors. CuSCN films with favorable optical property and hole extraction capability are prepared via a cost efficient and fast solvent removal method, demonstrating the potential for high-performance perovskite-based devices as transparent components. It is revealed that the band alignment of the device is effectively optimized with the presence of CuSCN HTLs,which can availably transport holes while block electrons at the Cs2AgBiBr6/CuSCN interface, resulting in remarkable improvement of photoresponse performance. The responsivity and detectivity are 0.34 A W^-1 and 1.03×10^13 Jones,respectively. In particular, the light current has a boost of almost 10 times. Furthermore, the photodetectors are integrated into a self-built light detection imaging system utilizing the focused laser scanning imaging mode. With illumination of as low as 5 nW cm^-2(405 nm), the image involving graphics and words with a size of 5 cm×5 cm can still be distinctly recognized. These results suggest the promising potential of all-inorganic perovskite-based devices for weak light detection and imaging applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:62074102,62104156,21961160720Open Research Fund of Songshan Lake Materials Laboratory,Grant/Award Number:2021SLABFK02+1 种基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2022A1515010979,2023A1515011256Science and Technology Plan Project of Shenzhen,Grant/Award。
文摘Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-processed thermodynamic or kinetic growth of high-quality narrow bandgap kesterite CZTSSe thin film is developed.A self-powered CZTSSe/CdS thin-film PD is then successfully fabricated.Under optimization of light absorber and heterojunction interface,especially tailoring the defect and carrier kinetics,it can achieve broadband response from300 to 1300 nm,accompaniedwith a high responsivity of 1.37A/W,specific detectivity(D*)up to 4.0×10^(14)Jones under 5 nW/cm^(2),a linear dynamic range(LDR)of 126 dB,and a maximum Ilight/Idark ratio of 1.3×10^(8)within the LDR,and ultrafast response speed(rise/decay time of 16 ns/85 ns),representing the leading-level performance to date,which is superior to those of commercial andwell-researched photodiodes.Additionally,an imaging system with a 905nm laser is built for weak light response evaluation,and can respond to 718 pW weak light and infrared imaging at a wavelength as low as 5 nW/cm2.It has also been employed for photoplethysmography detection of pulsating signals at both the finger and wrist,presenting obvious arterial blood volume changes,demonstrating great application potential in broadband and weak light photodetection scenarios.
文摘We propose ghost imaging(GI)with deep learning to improve detection speed.GI,which uses an illumination light with random patterns and a single-pixel detector,is correlation-based and thus suitable for detecting weak light.However,its detection time is too long for practical inspection.To overcome this problem,we applied a convolutional neural network that was constructed based on a classification of the causes of ghost image degradation.A feasibility experiment showed that when using a digital mirror device projector and a photodiode,the proposed method improved the quality of ghost images.
基金National Natural Science Foundation of China(62090054,61934003)National Key Research and Development Program of China(2022YFB2804504)+2 种基金Major Scientific and Technological Program of Jilin Province(20210301014GX)Jilin Provincial Development and Reform Commission Project(2020C056)Program for Jilin University Science and Technology Innovative Research Team(JLUSTIRT,2021TD-39).
文摘Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.
基金supported by the National Natural Science Foundation of China(62074111 and 62374115)the Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-07-E00096)the National Key Research and Development Program of China(2022YFB3203502)。
文摘有机-无机卤化物钙钛矿因其可溶液加工和优异的光电特性而在光电探测器(PD)中得到了广泛应用.然而,基于钙钛矿的PD一般需要电荷传输层提供足够的分离和传输驱动力,这会增加钙钛矿PD的材料成本.本研究通过溶液法制备了基于苯基三甲基氯化铵(PTACl)处理的无电荷传输层钙钛矿自供电PD.以(CsFAMA)Pb(BrI)3作为光活性层,这种三元阳离子混合卤化物钙钛矿沉积后的垂直分布差异为电荷分离和传输提供了驱动力,PTACl处理能加强电荷分离和运输.这种PD在自供电模式下表现出优异的光电探测性能,其中光暗电流比为1.8×10^(5),响应度为198 mA W^(−1),探测率为1.48×10^(13)/1.24×10^(11) Jones(暗/噪声电流法计算).没有封装的PD在700 h的测试中也表现出良好的空气稳定性,且该PD对0.64 nW cm^(−2)的弱光仍有明显的响应,PD阵列也验证了这种弱光检测能力.本工作制备的钙钛矿自供电PD为弱光检测的发展提供了一种简单可行的途径.
