A soluble low bandgap poly （pyrrole methine） with alkoxyl substituent, poly {（3-hexanoyl）pyrrole-[2,5- diyl（p-tetradecyloxybenzylidene）]} （PHPDTBE）, was synthesized and characterized by 1H nuclear magnetic res...A soluble low bandgap poly （pyrrole methine） with alkoxyl substituent, poly {（3-hexanoyl）pyrrole-[2,5- diyl（p-tetradecyloxybenzylidene）]} （PHPDTBE）, was synthesized and characterized by 1H nuclear magnetic resonance （1H-NMR）, Fourier transform-infrared （FT-IR）, elemental analysis （EA） and gel permeation chromatography （GPC）. PHPDTBE was readily soluble in weak polar organic solvents. The absorption peaks of PHPDTBE solution and film were located at around 458 and 484 nm, respectively. The optical bandgaps of PHPDTBE film for indirect allowed and direct allowed transitions were measured to be 1.66 and 2.35 eV, respectively. PHPDTBE film had few defects in the energy band and the Urbach energy of PHPDTBE film was calculated to be about 0.19 eV. The resonant third-order nonlinear optical susceptibilities of PHPDTBE solution and film measured by degenerate four-wave mixing （DFWM） technique at 532nm were all in the order of 10 8 esu, which was about 1-3 orders of magnitude larger than that of the other ordinary n-conjugation polymers.展开更多
To construct efficient low band gap polymers,increasing the Quinone structure of the polymer backbone could be one desirable strategy.In this work,two D–Q–A–Q polymers P1 and P2 were designed and synthesized with t...To construct efficient low band gap polymers,increasing the Quinone structure of the polymer backbone could be one desirable strategy.In this work,two D–Q–A–Q polymers P1 and P2 were designed and synthesized with thiophenopyrrole diketone(TPD)and benzothiadiazole(BT)unit as the core and ester linked thieno[3,4-b]thiophene(TT)segment as π-bridging,and the main focus is to make a comparative analysis of different cores in the influence of the optical,electrochemical,photochemical and morphological properties.Compared with the reported PBDTTEH–TBTTHD-i,P1 exhibited the decreased HOMO energy level of-5.38 e V and lower bandgap of 1.48 e V.Furthermore,when replaced with BT core,P2 showed a red-shifted absorption profile of polymer but with up-shifted HOMO energy level.When fabricated the photovoltaic devices in conventional structure,just as expected,the introduction of ester substituent made an obvious increase of VOC from 0.63 to 0.74 V for P1.Besides,due to the deep HOMO energy level,higher hole mobility and excellent phase separation with PC71 BM,a superior photovoltaic performance(PCE=7.13%)was obtained with a short-circuit current density(JSC)of 14.9 m A/cm^2,significantly higher than that of P2(PCE=2.23%).Generally,this study highlights that the strategy of inserting quinoid moieties into D–A polymers could be optional in LBG-polymers design and presents the importance and comparison of potentially competent core groups.展开更多
The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation...The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation applying density functional theory with generalized gradient approximation.The polymers and copolymers were modeled as 1D infinite system with periodical boundary condition along the molecular direction.It is concluded that the bandgap and HOCO/LUCO energies of conjugated polymers depend on both electron withdrawing/releasing effects and non-bonding interaction between a side group and the conjugated systems.展开更多
A high-PSRR high-order curvature-compensated CMOS bandgap voltage reference( BGR),which has the performances of high power supply rejection ratio( PSRR) and low temperature coefficient,is designed in SMIC 0. 18 μm CM...A high-PSRR high-order curvature-compensated CMOS bandgap voltage reference( BGR),which has the performances of high power supply rejection ratio( PSRR) and low temperature coefficient,is designed in SMIC 0. 18 μm CMOS process. Compared to the conventional curvature-compensated BGR which adopted a piecewise-linear current,the temperature characterize of the proposed BGR is effectively improved by adopting two kinds of current including a piecewise-linear current and a current proportional 1. 5 party to the absolute temperature T. By adopting a low dropout( LDO) regulator whose output voltage is the operating supply voltage of the proposed BGR core circuit instead of power supply voltage VDD,the proposed BGR with LDO regulator achieves a well PSRR performance than the BGR without LDO regulator. Simulation results show that the proposed BGR with LDO regulator achieves a temperature coefficient of 2. 1 × 10-6/ ℃ with a 1. 8 V power supply voltage and a line regulation of 4. 9 μV / V at 27 ℃. The proposed BGR with LDO regulator at 10 Hz,100 Hz,1 k Hz,10 k Hz and 100 k Hz have the PSRR of- 106. 388,- 106. 388,- 106. 38,- 105. 93 and-88. 67 d B respectively.展开更多
A novel defected ground structure （DGS） for the microstrip line is proposed in this paper. The DGS lattice has more defect parameters so that it can provide better performance than the conventional dumbbell-shaped D...A novel defected ground structure （DGS） for the microstrip line is proposed in this paper. The DGS lattice has more defect parameters so that it can provide better performance than the conventional dumbbell-shaped DGS. Selectivity is improved by 97.2% with a sharpness factor of 24.6%. The method is applied to the design of a low-pass filter to confirm validity of the proposed DGS.展开更多
基于声学黑洞(acoustic black hole, ABH)弧形梁体积小且模态频率丰富的特点,将声学黑洞弧形梁作为附加结构周期分布在直梁上,达到促进局域共振效应和拓宽低频带隙的作用,由此构建一种新的局域共振型声学超材料。针对局域共振型超材料,...基于声学黑洞(acoustic black hole, ABH)弧形梁体积小且模态频率丰富的特点,将声学黑洞弧形梁作为附加结构周期分布在直梁上,达到促进局域共振效应和拓宽低频带隙的作用,由此构建一种新的局域共振型声学超材料。针对局域共振型超材料,采用高斯展开法,建立其半解析理论分析模型,基于零空间法处理其内部连接以及周期边界条件,并通过有限元法验证半解析理论分析模型的准确性。分析和计算其能带结构,研究结构参数以及ABH效应对布拉格带隙以及局域共振带隙的影响机理。研究结果表明,该半解析理论模型能够对结构的带隙进行有效计算,附加弧形ABH的陷波机制能够促进结构的局域共振效应并对主梁进行有效减振,为声学黑洞声学超材料的应用提供了新的思路。展开更多
文摘A soluble low bandgap poly （pyrrole methine） with alkoxyl substituent, poly {（3-hexanoyl）pyrrole-[2,5- diyl（p-tetradecyloxybenzylidene）]} （PHPDTBE）, was synthesized and characterized by 1H nuclear magnetic resonance （1H-NMR）, Fourier transform-infrared （FT-IR）, elemental analysis （EA） and gel permeation chromatography （GPC）. PHPDTBE was readily soluble in weak polar organic solvents. The absorption peaks of PHPDTBE solution and film were located at around 458 and 484 nm, respectively. The optical bandgaps of PHPDTBE film for indirect allowed and direct allowed transitions were measured to be 1.66 and 2.35 eV, respectively. PHPDTBE film had few defects in the energy band and the Urbach energy of PHPDTBE film was calculated to be about 0.19 eV. The resonant third-order nonlinear optical susceptibilities of PHPDTBE solution and film measured by degenerate four-wave mixing （DFWM） technique at 532nm were all in the order of 10 8 esu, which was about 1-3 orders of magnitude larger than that of the other ordinary n-conjugation polymers.
基金the National Natural Science Foundation of China (21604092, 51573205 and 51773220)China Postdoctoral Science Foundation (2017M610453+1 种基金the Youth Innovation Promotion Association CAS (2016194) for financial supportthe CAS-TWAS President’s Fellowship Program for Ph.D
文摘To construct efficient low band gap polymers,increasing the Quinone structure of the polymer backbone could be one desirable strategy.In this work,two D–Q–A–Q polymers P1 and P2 were designed and synthesized with thiophenopyrrole diketone(TPD)and benzothiadiazole(BT)unit as the core and ester linked thieno[3,4-b]thiophene(TT)segment as π-bridging,and the main focus is to make a comparative analysis of different cores in the influence of the optical,electrochemical,photochemical and morphological properties.Compared with the reported PBDTTEH–TBTTHD-i,P1 exhibited the decreased HOMO energy level of-5.38 e V and lower bandgap of 1.48 e V.Furthermore,when replaced with BT core,P2 showed a red-shifted absorption profile of polymer but with up-shifted HOMO energy level.When fabricated the photovoltaic devices in conventional structure,just as expected,the introduction of ester substituent made an obvious increase of VOC from 0.63 to 0.74 V for P1.Besides,due to the deep HOMO energy level,higher hole mobility and excellent phase separation with PC71 BM,a superior photovoltaic performance(PCE=7.13%)was obtained with a short-circuit current density(JSC)of 14.9 m A/cm^2,significantly higher than that of P2(PCE=2.23%).Generally,this study highlights that the strategy of inserting quinoid moieties into D–A polymers could be optional in LBG-polymers design and presents the importance and comparison of potentially competent core groups.
基金Supported by the Department of Education of Shanghai(No.A10-0101-06-425).
文摘The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation applying density functional theory with generalized gradient approximation.The polymers and copolymers were modeled as 1D infinite system with periodical boundary condition along the molecular direction.It is concluded that the bandgap and HOCO/LUCO energies of conjugated polymers depend on both electron withdrawing/releasing effects and non-bonding interaction between a side group and the conjugated systems.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61471075)the 2013 Program for Innovation Team Building at Institutions of Higher Education in Chongqing(The Innovation Team of Smart Medical System and Key Technology)
文摘A high-PSRR high-order curvature-compensated CMOS bandgap voltage reference( BGR),which has the performances of high power supply rejection ratio( PSRR) and low temperature coefficient,is designed in SMIC 0. 18 μm CMOS process. Compared to the conventional curvature-compensated BGR which adopted a piecewise-linear current,the temperature characterize of the proposed BGR is effectively improved by adopting two kinds of current including a piecewise-linear current and a current proportional 1. 5 party to the absolute temperature T. By adopting a low dropout( LDO) regulator whose output voltage is the operating supply voltage of the proposed BGR core circuit instead of power supply voltage VDD,the proposed BGR with LDO regulator achieves a well PSRR performance than the BGR without LDO regulator. Simulation results show that the proposed BGR with LDO regulator achieves a temperature coefficient of 2. 1 × 10-6/ ℃ with a 1. 8 V power supply voltage and a line regulation of 4. 9 μV / V at 27 ℃. The proposed BGR with LDO regulator at 10 Hz,100 Hz,1 k Hz,10 k Hz and 100 k Hz have the PSRR of- 106. 388,- 106. 388,- 106. 38,- 105. 93 and-88. 67 d B respectively.
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No.T0102)
文摘A novel defected ground structure （DGS） for the microstrip line is proposed in this paper. The DGS lattice has more defect parameters so that it can provide better performance than the conventional dumbbell-shaped DGS. Selectivity is improved by 97.2% with a sharpness factor of 24.6%. The method is applied to the design of a low-pass filter to confirm validity of the proposed DGS.
文摘基于声学黑洞(acoustic black hole, ABH)弧形梁体积小且模态频率丰富的特点,将声学黑洞弧形梁作为附加结构周期分布在直梁上,达到促进局域共振效应和拓宽低频带隙的作用,由此构建一种新的局域共振型声学超材料。针对局域共振型超材料,采用高斯展开法,建立其半解析理论分析模型,基于零空间法处理其内部连接以及周期边界条件,并通过有限元法验证半解析理论分析模型的准确性。分析和计算其能带结构,研究结构参数以及ABH效应对布拉格带隙以及局域共振带隙的影响机理。研究结果表明,该半解析理论模型能够对结构的带隙进行有效计算,附加弧形ABH的陷波机制能够促进结构的局域共振效应并对主梁进行有效减振,为声学黑洞声学超材料的应用提供了新的思路。
