In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applic...In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.展开更多
Predicting the lifetime of polymeric insulators is one of the most important research topics in studying the life cycle of high voltage insulators in the power transmission and distribution networks. HTV （high temper...Predicting the lifetime of polymeric insulators is one of the most important research topics in studying the life cycle of high voltage insulators in the power transmission and distribution networks. HTV （high temperature vulcanized） silicone rubber is a high performance dielectric material used within electrical power equipment, in particular transmission and distribution insulators. In this paper, we proposed a new approach using the Newton＇s method and Lagrange method to predict the aging of HTV silicone rubber that are subjected to multiple stress conditions. Concentration of chemical elements such as carbon, oxygen, silicon and aluminum were obtained and evaluated using a SEM （scanning electron microscope） with EDS （energy dispersive X-ray spectroscopy）. Curve fitting using the Newton＇s and Lagrange interpolation methods yield useful linear interpolation equations that describe the aging characteristic of the specimens under study. This approach can be applied to predict the change in chemical concentration of polymeric insulators over the life cycle with good accuracy.展开更多
Due to their excellent electrical insulation properties and processability,polymer materials are used in many electrical products.It is widely believed that space charge plays an important role for the electric field ...Due to their excellent electrical insulation properties and processability,polymer materials are used in many electrical products.It is widely believed that space charge plays an important role for the electric field distribution,conduction,ageing,and electric breakdown of polymeric insulation.This paper reviews measurements and characteristics of space charge behavior which mainly determined by the pulsed electro-acoustic(PEA)measurement technique.Particular interests are the effects of the applied voltage,the electrodes,temperature,humidity,microstructure,additives,and filler materials on accumulation,distribution,transport,and the decay of space charge in polymeric materials.This review paper is to provide an overview on various space charge effects under different conditions,and also to summarize the information for polymeric materials with suppressed space charge and improved electrical behavior.展开更多
The multifrequency voltage(MFV)stress,including switching impulses and harmonics,commonly appearing in the modern power system will stimulate the multifrequency impedance dynamics behaviours of electrical insulation.T...The multifrequency voltage(MFV)stress,including switching impulses and harmonics,commonly appearing in the modern power system will stimulate the multifrequency impedance dynamics behaviours of electrical insulation.Therefore,this article presents a novel concept of insulation resilience response(IRR)by employing polymer insulation materials,which may be extended to electrical insulation resilience(EIR).The focus is on understanding reversible recovery performance and supporting physics-informed condition assessment for electrical insulation exposed to MFV.The underlying physical mechanisms and modelling methodologies are integrated to characterise the IRR behaviours of polymer insulation systems.The multifrequency dielectric/impedance properties of different resin dielectrics under diverse temperatures are comparatively investigated as proofofconcept cases.Furthermore,multidimensional sensitivity indicators are developed to quantify the electrical insulation resilience behaviour.A radar plot representation integrating resilience sensitivity indicators qualitatively assesses the IRR behaviours of polymer insulation systems.Additionally,a quantification methodology,including the resilience index(RI)and time-varied RI(TVRI),is proposed for the reversible recovery performance analysis for electrical insulation,respectively.Ultimately,an application-oriented framework derived from TVRI is provided to analyse the recovery performance evolution behaviours of electrical insulation under complex operating conditions.This offers a key theoretical foundation for insulation performance characterisation and condition analysis for high-voltage power equipment.展开更多
Polymer insulating through-silicon-vias （TSVs） is an attractive approach for high-performance 3D integration systems. To further demonstrate the polymer insulating TSVs, this paper investigates the thermal stability...Polymer insulating through-silicon-vias （TSVs） is an attractive approach for high-performance 3D integration systems. To further demonstrate the polymer insulating TSVs, this paper investigates the thermal stability by measuring the leakage current under bias-temperature condition, studies the thermal stress characteristics with Finite Element Analysis （FEA）, and tries to improve the thermal mechanical reliability of high-density TSVs array by optimizing the geometry parameters of pitch, liner and redistribution layer （RDL）. The electrical measurements show the polymer insulating TSVs can maintain good insulation capability （less than 2x 10TM A） under challenging bias-temperature conditions of 20 V and 200~C, despite the leakage degra- dation observation. The FEA results show that the thermal stress is significantly reduced at the sidewall, but highly concen- trates at the surface, which is the potential location of mechanical failure. And, the analysis results indicate that the polymer insulating TSVs （diameter of 10 μm, depth of 50 μm） array with a pitch of 20 μm, liner thickness of 1 μm and RDL radius of 9 μm has an optimized thermal-mechanical reliability for application.展开更多
Record-breaking organic solar cells(OSCs)based on blends of polymer donors and small molecule acceptors often show undesirable degradati on,which severely precludes their practical use.Herei n,we demonstrate a facile ...Record-breaking organic solar cells(OSCs)based on blends of polymer donors and small molecule acceptors often show undesirable degradati on,which severely precludes their practical use.Herei n,we demonstrate a facile and cost-effective approach to con struct thermally stable OSCs at 150℃ by incorporating a small amount of a polymer insulator polyacenaphthylene(PAC)with high glass-transition temperature over 230℃ into polymer:acceptor blends.The model PTB7-Th:EH-IDTBR blend with 10 wt%PAC maintained above 85%of its initial efficiency upon continuous heating at 150℃ for over 800 h,while the efficiency of the blend without PAC sharply dropped by 70%after-300 h.Owing to high miscibility with acceptors,PAC confines the motion of the acceptor molecules and suppresses the acceptor crystallization at elevated temperatures,leading to significantly improved stability.Importantly,the effectiveness of this blending approach was also validated in many other OSC systems,showing great potential for achieving high-performance thermally stable electronics.展开更多
基金supported by the National Key R&D Program(Grant No.2022YFA1203-100)sponsorship by Shanghai Sailing Program(Grant No.24YF2713800)+2 种基金financial support from the Local College Capacity Building Project of Shanghai Municipal Science and Technology Commission(Grant No.20010500700)the Natural Science Foundation of Shanghai(Grant No.23ZR1424300)Shanghai Shuguang Program(Grant No.22SG56)。
文摘In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.
文摘Predicting the lifetime of polymeric insulators is one of the most important research topics in studying the life cycle of high voltage insulators in the power transmission and distribution networks. HTV （high temperature vulcanized） silicone rubber is a high performance dielectric material used within electrical power equipment, in particular transmission and distribution insulators. In this paper, we proposed a new approach using the Newton＇s method and Lagrange method to predict the aging of HTV silicone rubber that are subjected to multiple stress conditions. Concentration of chemical elements such as carbon, oxygen, silicon and aluminum were obtained and evaluated using a SEM （scanning electron microscope） with EDS （energy dispersive X-ray spectroscopy）. Curve fitting using the Newton＇s and Lagrange interpolation methods yield useful linear interpolation equations that describe the aging characteristic of the specimens under study. This approach can be applied to predict the change in chemical concentration of polymeric insulators over the life cycle with good accuracy.
文摘Due to their excellent electrical insulation properties and processability,polymer materials are used in many electrical products.It is widely believed that space charge plays an important role for the electric field distribution,conduction,ageing,and electric breakdown of polymeric insulation.This paper reviews measurements and characteristics of space charge behavior which mainly determined by the pulsed electro-acoustic(PEA)measurement technique.Particular interests are the effects of the applied voltage,the electrodes,temperature,humidity,microstructure,additives,and filler materials on accumulation,distribution,transport,and the decay of space charge in polymeric materials.This review paper is to provide an overview on various space charge effects under different conditions,and also to summarize the information for polymeric materials with suppressed space charge and improved electrical behavior.
基金supported by the Science and Technology Project of State Grid Corporation of China(Grant 5500-202455120A-1-1-ZN).
文摘The multifrequency voltage(MFV)stress,including switching impulses and harmonics,commonly appearing in the modern power system will stimulate the multifrequency impedance dynamics behaviours of electrical insulation.Therefore,this article presents a novel concept of insulation resilience response(IRR)by employing polymer insulation materials,which may be extended to electrical insulation resilience(EIR).The focus is on understanding reversible recovery performance and supporting physics-informed condition assessment for electrical insulation exposed to MFV.The underlying physical mechanisms and modelling methodologies are integrated to characterise the IRR behaviours of polymer insulation systems.The multifrequency dielectric/impedance properties of different resin dielectrics under diverse temperatures are comparatively investigated as proofofconcept cases.Furthermore,multidimensional sensitivity indicators are developed to quantify the electrical insulation resilience behaviour.A radar plot representation integrating resilience sensitivity indicators qualitatively assesses the IRR behaviours of polymer insulation systems.Additionally,a quantification methodology,including the resilience index(RI)and time-varied RI(TVRI),is proposed for the reversible recovery performance analysis for electrical insulation,respectively.Ultimately,an application-oriented framework derived from TVRI is provided to analyse the recovery performance evolution behaviours of electrical insulation under complex operating conditions.This offers a key theoretical foundation for insulation performance characterisation and condition analysis for high-voltage power equipment.
文摘Polymer insulating through-silicon-vias （TSVs） is an attractive approach for high-performance 3D integration systems. To further demonstrate the polymer insulating TSVs, this paper investigates the thermal stability by measuring the leakage current under bias-temperature condition, studies the thermal stress characteristics with Finite Element Analysis （FEA）, and tries to improve the thermal mechanical reliability of high-density TSVs array by optimizing the geometry parameters of pitch, liner and redistribution layer （RDL）. The electrical measurements show the polymer insulating TSVs can maintain good insulation capability （less than 2x 10TM A） under challenging bias-temperature conditions of 20 V and 200~C, despite the leakage degra- dation observation. The FEA results show that the thermal stress is significantly reduced at the sidewall, but highly concen- trates at the surface, which is the potential location of mechanical failure. And, the analysis results indicate that the polymer insulating TSVs （diameter of 10 μm, depth of 50 μm） array with a pitch of 20 μm, liner thickness of 1 μm and RDL radius of 9 μm has an optimized thermal-mechanical reliability for application.
基金supported by the National Natural Science Foundation of China(Nos.52073207,22075200,and 51703158)L.Y.expresses thanks for the start-up grant of Peiyang Scholar program from Tianjin University and the Open Fund of the State Key Laboratory of Luminesce nt Materials and Devices(South China University of Technology,No.2020-skllmd-11)+1 种基金M.L.thanks the Peiyang Young Junior Faculty Program of Tianjin University(No.2019XRG-0021)L.Y.acknowledges the merit beamtime(Project ID:15692)approved by the Australian Synchrotron and beamtime(Project ID:2020-BEPC-PT-004082)approved by Beijing Synchro-tron Radiati on Facility.
文摘Record-breaking organic solar cells(OSCs)based on blends of polymer donors and small molecule acceptors often show undesirable degradati on,which severely precludes their practical use.Herei n,we demonstrate a facile and cost-effective approach to con struct thermally stable OSCs at 150℃ by incorporating a small amount of a polymer insulator polyacenaphthylene(PAC)with high glass-transition temperature over 230℃ into polymer:acceptor blends.The model PTB7-Th:EH-IDTBR blend with 10 wt%PAC maintained above 85%of its initial efficiency upon continuous heating at 150℃ for over 800 h,while the efficiency of the blend without PAC sharply dropped by 70%after-300 h.Owing to high miscibility with acceptors,PAC confines the motion of the acceptor molecules and suppresses the acceptor crystallization at elevated temperatures,leading to significantly improved stability.Importantly,the effectiveness of this blending approach was also validated in many other OSC systems,showing great potential for achieving high-performance thermally stable electronics.
