An indoor positioning system( IPS) is designed to realize positioning and tracking of mobile targets,by taking advantages of both the visible light communication( VLC) and inertial measurement unit( IMU). The platform...An indoor positioning system( IPS) is designed to realize positioning and tracking of mobile targets,by taking advantages of both the visible light communication( VLC) and inertial measurement unit( IMU). The platform of the IPS is designed,which consists of the light-emitting diode( LED)based transmitter,the receiver and the positioning server. To reduce the impact caused by measurement errors,both inertial sensing data and the received signal strength( RSS) from the VLC are calibrated. Then,a practical propagation model is established to obtain the distance between the transmitter and the receiver from the RSS measurements. Furthermore,a hybrid positioning algorithm is proposed by using the adaptive Kalman filter( AKF) and the weighted least squares( WLS)trilateration to estimate the positions of the mobile targets.Experimental results show that the developed IPS using the proposed hybrid positioning algorithm can extend the localization area of VLC,mitigate the IMU drifts and improve the positioning accuracy of mobile targets.展开更多
Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, e...Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.展开更多
Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2...Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.展开更多
A series of N-dioctylmethyl-2,7-carbazole-alt-5,7-bis（thiophen-2-yl）-2,3-biphenylthieno[3,4-b]pyrazine （PCz-3ThPz-Ph） co- polymeric derivatives appending various donor units in two phenyl rings, namely, PCz-3ThPz-...A series of N-dioctylmethyl-2,7-carbazole-alt-5,7-bis（thiophen-2-yl）-2,3-biphenylthieno[3,4-b]pyrazine （PCz-3ThPz-Ph） co- polymeric derivatives appending various donor units in two phenyl rings, namely, PCz-3ThPz-PhTh, PCz-3ThPz-PhF1, PCz-3ThPz-PhCz, and PCz-3ThPz-PhTpa were synthesized and characterized. The effect of these appending donor units, e.g., thiophene （Th）, fluorene （F1）, carbazole （Cz）, and triarylamine （Tpa）, was investigated on dispersible, optical, electrochemical, and photovoltaic properties for their polymers. The copolymers of PCz-3ThPz-PhCz and PCz-3ThPz-PhTpa containing Cz or Tpa units exhibited higher short-circuit current density （Jsc） and power conversion efficiency （PCE） in their bulk heterojunction polymeric solar cells. The highest PCE of 1.66% and Jsc of 7.16 mA cm-2 were obtained in a device with the PCz-3ThPz-PhCz/PC61BM blend under AM 1.5 G irradiation （100 mW cm 2）; these values are 1.78 and 1.59 times higher than the corresponding values for the PCz-3ThPz-Ph-based device. When PC61BM was placed by PC71BM, the PCz-3ThPz-PhCz-based device displayed an enhanced PCE of 2.98% and a Jsc of 10.88 mA cm-2. This work demonstrated that appending additional hole-transporting units of Cz and Tpa into the side-chain of a polymer with a D-A backbone can significantly enhance the photovoltaic performance of their resultant polymers.展开更多
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfe...A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-on voltages of their single-layer electroluminescent (EL) devices (ITO/PEDOT/polymer/LiF/Al) were at 6.1-4.0 V,which were much lower than that of PFO (7.0 V).The maximum brightness,current efficiency,and external quantum efficiency of all PFBY copolymers were higher than those of the PFO homopolymer.The single-layer device of PFBY5 was the best one in the copolymers,with a maximum brightness of 485 cd/m2,a current efficiency of 0.29 cd/A,and an external quantum efficiency of 0.10%.The introduction of PVK and TPBI for the multilayer device of PFBY5 increased the device efficiencies,which showed a maximum brightness of 3012 cd/m2,a maximum current efficiency of 1.81 cd/A,and an external quantum efficiency of 0.66%.展开更多
A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination ...A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC71BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G,100 mW cm-2, which is the highest value for PP-based PSCs.展开更多
Dual-modal surface enhanced Raman spectrum(SERS)-fluorescence polymer/metal hybrid complexes have been prepared for tracing drug release process in tumor cells. Firstly, the hyperbranched poly((S-(4-vinyl) benzyl S′-...Dual-modal surface enhanced Raman spectrum(SERS)-fluorescence polymer/metal hybrid complexes have been prepared for tracing drug release process in tumor cells. Firstly, the hyperbranched poly((S-(4-vinyl) benzyl S′-propyltrithiocarbonate)-co-(poly(ethylene glycol) methacrylate))(HPVBEG) was synthesized via the combination of reversible addition-fragmentation chain-transfer(RAFT) polymerization and self-condensing vinyl polymerization(SCVP). Subsequently, the anticancer drug doxorubicin(DOX) was linked to HPVBEG via pH sensitive Schiff base bonds to form HPVBEG-g-DOX conjugates.Through aminolysis reaction, HPVBEG-g-DOX was coordinated with gold nanoparticles(GNP), resulting in the formation of HPVBEG-g-DOX/GNP complexes. In neutral condition, the HPVBEG-g-DOX/GNP complexes were stable, and DOX was bound to the surface of GNPs. Therefore, the SERS of DOX could be observed, while the fluorescence of DOX was quenched by GNPs. Under an acidic environment, DOX was released from the surface of GNPs with breakage of Schiff base bonds.Thus, the SERS signal of DOX was gradually reduced. Correspondingly, the fluorescence signal of DOX was enhanced.Through dual-modal SERS-fluorescence technique, the DOX delivery and release process was traced in tumor cells. Moreover,the viability of MCF-7 cells incubated with HPVBEG-g-DOX/GNP complexes was investigated by Cell Counting Kit-8(CCK-8) assay. The experimental results showed that HPVBEG-g-DOX/GNP complexes had similar proliferation inhibition effect compared with free DOX. Definitely, the dual-modal SERS-fluorescence complexes for tracing drug delivery and release will have promising prospects on tumor diagnosis and therapy.展开更多
基金The National Natural Science Foundation of China(No.61741102,61471164,61601122)the Fundamental Research Funds for the Central Universities(No.SJLX_160040)
文摘An indoor positioning system( IPS) is designed to realize positioning and tracking of mobile targets,by taking advantages of both the visible light communication( VLC) and inertial measurement unit( IMU). The platform of the IPS is designed,which consists of the light-emitting diode( LED)based transmitter,the receiver and the positioning server. To reduce the impact caused by measurement errors,both inertial sensing data and the received signal strength( RSS) from the VLC are calibrated. Then,a practical propagation model is established to obtain the distance between the transmitter and the receiver from the RSS measurements. Furthermore,a hybrid positioning algorithm is proposed by using the adaptive Kalman filter( AKF) and the weighted least squares( WLS)trilateration to estimate the positions of the mobile targets.Experimental results show that the developed IPS using the proposed hybrid positioning algorithm can extend the localization area of VLC,mitigate the IMU drifts and improve the positioning accuracy of mobile targets.
基金Projects(50803074, 50633050) supported by the National Natural Science Foundation of ChinaProject supported by the Opening Fund of State Key Laboratory of Powder MetallurgyStart-up Fund of Central South University, China
文摘Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.
基金the National Natural Science Foundation of China (51273053, 21104012, 21284034 and 61106017)the Natural Science Foundation of Zhejiang Province (Y4110331)+1 种基金the Program for Changjiang Scholars and Innovative Research Teams in Chinese Universities (IRT 1231)the Project of Zhejiang Key Scientific and Technological Innovation Team (2010R50017)
文摘Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.
基金supported by the major program for cultivation of the National Natural Science Foundation of China(91233112)the National Natural Science Foundation of China(21172187,50973093,51403178)+3 种基金the Innovation Group and Xiangtan Joint Project of the Hunan Natural Science Foundation(12JJ7002,12JJ8001)the Scientific Research Fund of Hunan Provincial Education Department(11CY023,12B123)the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology,No.2014-skllmd-10)the Postgraduate Science Foundation for Innovation in Hunan Province(CX2014B257,CX2011B263)
文摘A series of N-dioctylmethyl-2,7-carbazole-alt-5,7-bis（thiophen-2-yl）-2,3-biphenylthieno[3,4-b]pyrazine （PCz-3ThPz-Ph） co- polymeric derivatives appending various donor units in two phenyl rings, namely, PCz-3ThPz-PhTh, PCz-3ThPz-PhF1, PCz-3ThPz-PhCz, and PCz-3ThPz-PhTpa were synthesized and characterized. The effect of these appending donor units, e.g., thiophene （Th）, fluorene （F1）, carbazole （Cz）, and triarylamine （Tpa）, was investigated on dispersible, optical, electrochemical, and photovoltaic properties for their polymers. The copolymers of PCz-3ThPz-PhCz and PCz-3ThPz-PhTpa containing Cz or Tpa units exhibited higher short-circuit current density （Jsc） and power conversion efficiency （PCE） in their bulk heterojunction polymeric solar cells. The highest PCE of 1.66% and Jsc of 7.16 mA cm-2 were obtained in a device with the PCz-3ThPz-PhCz/PC61BM blend under AM 1.5 G irradiation （100 mW cm 2）; these values are 1.78 and 1.59 times higher than the corresponding values for the PCz-3ThPz-Ph-based device. When PC61BM was placed by PC71BM, the PCz-3ThPz-PhCz-based device displayed an enhanced PCE of 2.98% and a Jsc of 10.88 mA cm-2. This work demonstrated that appending additional hole-transporting units of Cz and Tpa into the side-chain of a polymer with a D-A backbone can significantly enhance the photovoltaic performance of their resultant polymers.
基金supported by the National Natural Science Foundation of China (50803062,60977026 & 20904055)the Science Fund for Creative Research Groups (20621401)the Natural Basic Research Foundation of China (973 Program,2009CB623601)
文摘A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-on voltages of their single-layer electroluminescent (EL) devices (ITO/PEDOT/polymer/LiF/Al) were at 6.1-4.0 V,which were much lower than that of PFO (7.0 V).The maximum brightness,current efficiency,and external quantum efficiency of all PFBY copolymers were higher than those of the PFO homopolymer.The single-layer device of PFBY5 was the best one in the copolymers,with a maximum brightness of 485 cd/m2,a current efficiency of 0.29 cd/A,and an external quantum efficiency of 0.10%.The introduction of PVK and TPBI for the multilayer device of PFBY5 increased the device efficiencies,which showed a maximum brightness of 3012 cd/m2,a maximum current efficiency of 1.81 cd/A,and an external quantum efficiency of 0.66%.
基金supported by the National Natural Science Foundation of China (51673205, 21506258)National Key Research & Development Projects of China (2017YFA0206600)+3 种基金Hunan Provincial Natural Science Foundation for Distinguished Young Scholars (2017JJ1029)Natural Science Foundation of Hunan Province (2016JJ3134)Project of Innovation-driven Plan in Central South University, China (2016CX035)the Fundamental Research Funds for the Central Universities of Central South University (2016zzts023)
文摘A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC71BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G,100 mW cm-2, which is the highest value for PP-based PSCs.
基金supported by the National Basic Research Program of China(2015CB931801)the National Natural Science Foundation of China(51473093)
文摘Dual-modal surface enhanced Raman spectrum(SERS)-fluorescence polymer/metal hybrid complexes have been prepared for tracing drug release process in tumor cells. Firstly, the hyperbranched poly((S-(4-vinyl) benzyl S′-propyltrithiocarbonate)-co-(poly(ethylene glycol) methacrylate))(HPVBEG) was synthesized via the combination of reversible addition-fragmentation chain-transfer(RAFT) polymerization and self-condensing vinyl polymerization(SCVP). Subsequently, the anticancer drug doxorubicin(DOX) was linked to HPVBEG via pH sensitive Schiff base bonds to form HPVBEG-g-DOX conjugates.Through aminolysis reaction, HPVBEG-g-DOX was coordinated with gold nanoparticles(GNP), resulting in the formation of HPVBEG-g-DOX/GNP complexes. In neutral condition, the HPVBEG-g-DOX/GNP complexes were stable, and DOX was bound to the surface of GNPs. Therefore, the SERS of DOX could be observed, while the fluorescence of DOX was quenched by GNPs. Under an acidic environment, DOX was released from the surface of GNPs with breakage of Schiff base bonds.Thus, the SERS signal of DOX was gradually reduced. Correspondingly, the fluorescence signal of DOX was enhanced.Through dual-modal SERS-fluorescence technique, the DOX delivery and release process was traced in tumor cells. Moreover,the viability of MCF-7 cells incubated with HPVBEG-g-DOX/GNP complexes was investigated by Cell Counting Kit-8(CCK-8) assay. The experimental results showed that HPVBEG-g-DOX/GNP complexes had similar proliferation inhibition effect compared with free DOX. Definitely, the dual-modal SERS-fluorescence complexes for tracing drug delivery and release will have promising prospects on tumor diagnosis and therapy.
