Presently,liquid crystal displays(LCDs)and organic light-emitting diode(OLED)displays are two dominant flat panel display technologies.Recently,inorganic mini-LEDs(mLEDs)and micro-LEDs(μLEDs)have emerged by significa...Presently,liquid crystal displays(LCDs)and organic light-emitting diode(OLED)displays are two dominant flat panel display technologies.Recently,inorganic mini-LEDs(mLEDs)and micro-LEDs(μLEDs)have emerged by significantly enhancing the dynamic range of LCDs or as sunlight readable emissive displays.“mLED,OLED,orμLED:who wins?”is a heated debatable question.In this review,we conduct a comprehensive analysis on the material properties,device structures,and performance of mLED/μLED/OLED emissive displays and mLED backlit LCDs.We evaluate the power consumption and ambient contrast ratio of each display in depth and systematically compare the motion picture response time,dynamic range,and adaptability to flexible/transparent displays.The pros and cons of mLED,OLED,andμLED displays are analysed,and their future perspectives are discussed.展开更多
Silver nanowire films are promising alternatives to tin-doped indium oxide(ITO)films as transparent conductive electrodes.In this paper,we report the use of vacuum filtration and a polydimethylsiloxane(PDMS)-assisted ...Silver nanowire films are promising alternatives to tin-doped indium oxide(ITO)films as transparent conductive electrodes.In this paper,we report the use of vacuum filtration and a polydimethylsiloxane(PDMS)-assisted transfer printing technique to fabricate silver nanowire films on both rigid and flexible substrates,bringing advantages such as the capability of patterned transfer,the best performance among various ITO alternatives(10Ω/sq at 85%transparency),and good adhesion to the underlying substrate,thus eliminating the previously reported adhesion problem.In addition,our method also allows the preparation of high quality patterned films of silver nanowires with different line widths and shapes in a matter of few minutes,making it a scalable process.Furthermore,use of an anodized aluminum oxide(AAO)membrane in the transfer process allows annealing of nanowire films at moderately high temperature to obtain films with extremely high conductivity and good transparency.Using this transfer technique,we obtained silver nanowire films on a flexible polyethylene terephthalate(PET)substrate with a transparency of 85%,a sheet resistance of 10Ω/sq,with good mechanical flexibility.Detailed analysis revealed that the Ag nanowire network exhibits two-dimensional percolation behavior with good agreement between experimentally observed and theoretically predicted values of critical volume。展开更多
Silver nanowires （AgNWs） surrounded by insulating poly（vinylpyrrolidone） have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heatt...Silver nanowires （AgNWs） surrounded by insulating poly（vinylpyrrolidone） have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heattreatment at about 200 ℃ which forms connecting junctions between AgNWs. Such a heating process is, however, one of the drawbacks of the fabrication of AgNW electrodes on heat-sensitive substrates. Here it has been demonstrated that the electrical conductivity of AgNW electrodes can be improved by mechanical pressing at 25 MPa for 5 s at room temperature. This simple process results in a low sheet resistance of 8.6 Ω/square and a transparency of 80.0%, equivalent to the properties of the AgNW electrodes heated at 200 ℃. This technique makes it possible to fabricate AgNW transparent electrodes on heat-sensitive substrates. The AgNW electrodes on poly（ethylene terephthalate） films exhibited high stability of their electrical conductivities against the repeated bending test. In addition, the surface roughness of the pressed AgNW electrodes is one-third of that of the heat-treated electrode because the AgNW junctions are mechanically compressed. As a result, an organic solar cell fabricated on the pressed AgNW electrodes exhibited a power conversion as much as those fabricated on indium tin oxide electrodes. These findings enable continuous roll-to-roll processing at room temperature, resulting in relatively simple, inexpensive, and scalable processing that is suitable for forthcoming technologies such as organic solar cells, flexible displays, and touch screens.展开更多
The development of pressure sensors with highly sensitivity, fast response and facile fabrication technique is desirable for wearable electronics. Here, we successfully fabricated a flexible transparent capacitive pre...The development of pressure sensors with highly sensitivity, fast response and facile fabrication technique is desirable for wearable electronics. Here, we successfully fabricated a flexible transparent capacitive pressure sensor based on patterned microstructured silver nanowires(AgNWs)/polydimethylsiloxane(PDMS) composite dielectrics. Compared with the pure PDMS dielectric layer with planar structures, the patterned microstructured sensor exhibits a higher sensitivity(0.831 kPa^-1, <0.5 kPa), a lower detection limit,good stability and durability. The enhanced sensing mechanism about the conductive filler content and the patterned microstructures has also been discussed. A 5×5 sensor array was then fabricated to be used as flexible and transparent wearable touch keyboards systems. The fabricated pressure sensor has great potential in the future electronic skin area.展开更多
A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare function...A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare functional ceramics with high Ga concentration,and Y3Ga5O12(YGG)transparent ceramic was successfully prepared for the first time.According to the variation of Al/Ga ratio,regulation of band structure and luminescence properties of YAGG:Ce transparent ceramics were effectively investigated.When Ga substitutes Al sites,the tetrahedral site is more favorable compared to the octahedral site for Ga to occupy according to the first-principle calculation.A continuous blue shift of the emission from 565 to 515 nm was achieved as Ga was gradually introduced into Y3Al5O12:Ce matrix.High quality green light was obtained by coupling the YAGG:Ce ceramics with commercial blue InGaN chips.Transparent luminescence ceramics accomplished in this work can be quite prospective for high power LED application.展开更多
Transparent brittle materials such as glass and sapphire are widely concerned and applied in consumer electronics, optoelectronic devices, etc. due to their excellent physical and chemical stability and good transpare...Transparent brittle materials such as glass and sapphire are widely concerned and applied in consumer electronics, optoelectronic devices, etc. due to their excellent physical and chemical stability and good transparency. Growing research attention has been paid to developing novel methods for high-precision and high-quality machining of transparent brittle materials in the past few decades. Among the various techniques, laser machining has been proved to be an effective and flexible way to process all kinds of transparent brittle materials. In this review, a series of laser machining methods, e.g. laser full cutting, laser scribing, laser stealth dicing, laser filament, laser induced backside dry etching (LIBDE), and laser induced backside wet etching (LIBWE) are summarized. Additionally, applications of these techniques in micromachining, drilling and cutting, and patterning are introduced in detail. Current challenges and future prospects in this field are also discussed.展开更多
Transparent electrodes made of silver nanowires （AgNWs） exhibit higher flexibility when compared to those made of tin doped indium oxide （ITO） and are expected to be applied in plastic electronics. However, these ...Transparent electrodes made of silver nanowires （AgNWs） exhibit higher flexibility when compared to those made of tin doped indium oxide （ITO） and are expected to be applied in plastic electronics. However, these transparent electrodes composed of AgNWs show high haze because the wires cause strong light scattering in the visible range. Reduction of the wire diameter has been proposed as a way to weaken light scattering, although there have seldom been any studies focusing on the haze because of the difficulty involved in controlling the wire diameter. In this report, we show that the haze can be easily reduced by increasing the length of AgNWs with a large diameter. Ultra-long （u-long） AgNWs with lengths in the range of 20-100 μm and a maximum length of 230 μm have been successfully synthesized by adjusting the reaction temperature and the stirring speed of a one-step polyol process. Compared to typical AgNWs （with diameter and length of 70 nm and 10 μm, respectively） and ITO, a transparent electrode consisting of u-long AgNWs 91 nm in diameter demonstrated a low haze of 3.4%-1.6% and a low sheet resistance of 24-109 Ω/sq. at a transmittance of 94%-97%. Even when fabricated at room temperature without any post-treatment, the electrodes composed of u-long AgNWs achieved a sheet resistance of 19 Ω/sq, at a transmittance of 80%, which is six orders of magnitude lower than that of typical AgNWs.展开更多
A series of YAG:Ce,Mn transparent ceramics were prepared via a solid-state reaction-vacuum sintering method.The effects of various Mn^2+–Si4+pair doping levels on the structure,transmittance,and luminescence properti...A series of YAG:Ce,Mn transparent ceramics were prepared via a solid-state reaction-vacuum sintering method.The effects of various Mn^2+–Si4+pair doping levels on the structure,transmittance,and luminescence properties were systematically investigated.These transparent ceramics have average grain sizes of 10–16μm,clean grain boundaries,and excellent transmittance up to 83.4%at 800 nm.Under the excitation of 460 nm,three obvious emission peaks appear at 533,590,and 745 nm,which can be assigned to the transition 5 d→4 f of Ce^3+and 4 T1→6 A1 of Mn^2+.Thus,the Mn^2+–Si4+pairs can effectively modulate the emission spectrum by compensating broad orange-red and red spectrum component to yield high quality warm white light.After the optimized YAG:Ce,Mn transparent ceramic packaged with blue light-emitting diode(LED)chips,correlated color temperature(CCT)as low as 3723 K and luminous efficiency(LE)as high as 96.54 lm/W were achieved,implying a very promising candidate for application in white light-emitting diodes(WLEDs)industry.展开更多
Metasurfaces, two-dimensional equivalents of metamaterials, are engineered surfaces consisting of deep subwavelength features that have full control of the electromagnetic waves. Metasurfaces are not only being applie...Metasurfaces, two-dimensional equivalents of metamaterials, are engineered surfaces consisting of deep subwavelength features that have full control of the electromagnetic waves. Metasurfaces are not only being applied to the current de-vices throughout the electromagnetic spectrum from microwave to optics but also inspiring many new thrilling applica-tions such as programmable on-demand optics and photonics in future. In order to overcome the limits imposed by pas-sive metasurfaces, extensive researches have been put on utilizing different materials and mechanisms to design active metasurfaces. In this paper, we review the recent progress in tunable and reconfigurable metasurfaces and metadevicesthrough the different active materials deployed together with the different control mechanisms including electrical, ther-mal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.展开更多
Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties.With excellent ...Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties.With excellent electrical conductivity of 6000 S/cm, which is independent on chirality, graphene is a promising material for high-performance nanoelectronics, transparent conductor, as well as polymer composites. On account of its Young's Modulus of 1 TPa and ultimate strength of 130 GPa, isolated graphene sheet is considered to be among the strongest materials ever measured. Comparable with the single-walled carbon nanotube bundle,graphene has a thermal conductivity of 5000 W/(m·K), which suggests a potential application of graphene in polymer matrix for improving thermal properties of the graphene/polymer composite. Furthermore, graphene exhibits a very high surface area, up to a value of 2630 m^2/g. All of these outstanding properties suggest a wide application for this nanometer-thick, two-dimensional carbon material. This review article presents an overview of the significant advancement in graphene research: preparation, functionalization as well as the properties of graphene will be discussed. In addition, the feasibility and potential applications of graphene in areas, such as sensors, nanoelectronics and nanocomposites materials, will also be reviewed.展开更多
基金partial financial support under grant FA9550-14-1-0279.
文摘Presently,liquid crystal displays(LCDs)and organic light-emitting diode(OLED)displays are two dominant flat panel display technologies.Recently,inorganic mini-LEDs(mLEDs)and micro-LEDs(μLEDs)have emerged by significantly enhancing the dynamic range of LCDs or as sunlight readable emissive displays.“mLED,OLED,orμLED:who wins?”is a heated debatable question.In this review,we conduct a comprehensive analysis on the material properties,device structures,and performance of mLED/μLED/OLED emissive displays and mLED backlit LCDs.We evaluate the power consumption and ambient contrast ratio of each display in depth and systematically compare the motion picture response time,dynamic range,and adaptability to flexible/transparent displays.The pros and cons of mLED,OLED,andμLED displays are analysed,and their future perspectives are discussed.
基金funded by the U.S.Department of Energy,Office of Science and Office of Basic Energy Sciences under Award No.DE-SC0001013.
文摘Silver nanowire films are promising alternatives to tin-doped indium oxide(ITO)films as transparent conductive electrodes.In this paper,we report the use of vacuum filtration and a polydimethylsiloxane(PDMS)-assisted transfer printing technique to fabricate silver nanowire films on both rigid and flexible substrates,bringing advantages such as the capability of patterned transfer,the best performance among various ITO alternatives(10Ω/sq at 85%transparency),and good adhesion to the underlying substrate,thus eliminating the previously reported adhesion problem.In addition,our method also allows the preparation of high quality patterned films of silver nanowires with different line widths and shapes in a matter of few minutes,making it a scalable process.Furthermore,use of an anodized aluminum oxide(AAO)membrane in the transfer process allows annealing of nanowire films at moderately high temperature to obtain films with extremely high conductivity and good transparency.Using this transfer technique,we obtained silver nanowire films on a flexible polyethylene terephthalate(PET)substrate with a transparency of 85%,a sheet resistance of 10Ω/sq,with good mechanical flexibility.Detailed analysis revealed that the Ag nanowire network exhibits two-dimensional percolation behavior with good agreement between experimentally observed and theoretically predicted values of critical volume。
文摘Silver nanowires （AgNWs） surrounded by insulating poly（vinylpyrrolidone） have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heattreatment at about 200 ℃ which forms connecting junctions between AgNWs. Such a heating process is, however, one of the drawbacks of the fabrication of AgNW electrodes on heat-sensitive substrates. Here it has been demonstrated that the electrical conductivity of AgNW electrodes can be improved by mechanical pressing at 25 MPa for 5 s at room temperature. This simple process results in a low sheet resistance of 8.6 Ω/square and a transparency of 80.0%, equivalent to the properties of the AgNW electrodes heated at 200 ℃. This technique makes it possible to fabricate AgNW transparent electrodes on heat-sensitive substrates. The AgNW electrodes on poly（ethylene terephthalate） films exhibited high stability of their electrical conductivities against the repeated bending test. In addition, the surface roughness of the pressed AgNW electrodes is one-third of that of the heat-treated electrode because the AgNW junctions are mechanically compressed. As a result, an organic solar cell fabricated on the pressed AgNW electrodes exhibited a power conversion as much as those fabricated on indium tin oxide electrodes. These findings enable continuous roll-to-roll processing at room temperature, resulting in relatively simple, inexpensive, and scalable processing that is suitable for forthcoming technologies such as organic solar cells, flexible displays, and touch screens.
基金supported by the National Natural Science Foundation for Distinguished Young Scholars of China(NSFC,61625404)the Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-JWC004)the NSFC(61504136)
文摘The development of pressure sensors with highly sensitivity, fast response and facile fabrication technique is desirable for wearable electronics. Here, we successfully fabricated a flexible transparent capacitive pressure sensor based on patterned microstructured silver nanowires(AgNWs)/polydimethylsiloxane(PDMS) composite dielectrics. Compared with the pure PDMS dielectric layer with planar structures, the patterned microstructured sensor exhibits a higher sensitivity(0.831 kPa^-1, <0.5 kPa), a lower detection limit,good stability and durability. The enhanced sensing mechanism about the conductive filler content and the patterned microstructures has also been discussed. A 5×5 sensor array was then fabricated to be used as flexible and transparent wearable touch keyboards systems. The fabricated pressure sensor has great potential in the future electronic skin area.
基金supported by the National Key R & D Program of China (2016YFC0101800)National Natural Science Foundation of China (51672286, U1832159, 51772185)Science and Technology Major Project of Ningbo Municipality (2017C110028)
文摘A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare functional ceramics with high Ga concentration,and Y3Ga5O12(YGG)transparent ceramic was successfully prepared for the first time.According to the variation of Al/Ga ratio,regulation of band structure and luminescence properties of YAGG:Ce transparent ceramics were effectively investigated.When Ga substitutes Al sites,the tetrahedral site is more favorable compared to the octahedral site for Ga to occupy according to the first-principle calculation.A continuous blue shift of the emission from 565 to 515 nm was achieved as Ga was gradually introduced into Y3Al5O12:Ce matrix.High quality green light was obtained by coupling the YAGG:Ce ceramics with commercial blue InGaN chips.Transparent luminescence ceramics accomplished in this work can be quite prospective for high power LED application.
基金National Natural Science Foundation of China (51575114 and 51805093)National Key R&D Program of China (2018YFB1107700)Guangzhou Science and Technology Project (201607010156).
文摘Transparent brittle materials such as glass and sapphire are widely concerned and applied in consumer electronics, optoelectronic devices, etc. due to their excellent physical and chemical stability and good transparency. Growing research attention has been paid to developing novel methods for high-precision and high-quality machining of transparent brittle materials in the past few decades. Among the various techniques, laser machining has been proved to be an effective and flexible way to process all kinds of transparent brittle materials. In this review, a series of laser machining methods, e.g. laser full cutting, laser scribing, laser stealth dicing, laser filament, laser induced backside dry etching (LIBDE), and laser induced backside wet etching (LIBWE) are summarized. Additionally, applications of these techniques in micromachining, drilling and cutting, and patterning are introduced in detail. Current challenges and future prospects in this field are also discussed.
文摘Transparent electrodes made of silver nanowires （AgNWs） exhibit higher flexibility when compared to those made of tin doped indium oxide （ITO） and are expected to be applied in plastic electronics. However, these transparent electrodes composed of AgNWs show high haze because the wires cause strong light scattering in the visible range. Reduction of the wire diameter has been proposed as a way to weaken light scattering, although there have seldom been any studies focusing on the haze because of the difficulty involved in controlling the wire diameter. In this report, we show that the haze can be easily reduced by increasing the length of AgNWs with a large diameter. Ultra-long （u-long） AgNWs with lengths in the range of 20-100 μm and a maximum length of 230 μm have been successfully synthesized by adjusting the reaction temperature and the stirring speed of a one-step polyol process. Compared to typical AgNWs （with diameter and length of 70 nm and 10 μm, respectively） and ITO, a transparent electrode consisting of u-long AgNWs 91 nm in diameter demonstrated a low haze of 3.4%-1.6% and a low sheet resistance of 24-109 Ω/sq. at a transmittance of 94%-97%. Even when fabricated at room temperature without any post-treatment, the electrodes composed of u-long AgNWs achieved a sheet resistance of 19 Ω/sq, at a transmittance of 80%, which is six orders of magnitude lower than that of typical AgNWs.
基金the CAS Priority Research program(XDB20010300,XDA21010204)National Natural Science Foundation of China(201501178)Natural Science Foundation of Fujian Province(2017H0048)。
文摘A series of YAG:Ce,Mn transparent ceramics were prepared via a solid-state reaction-vacuum sintering method.The effects of various Mn^2+–Si4+pair doping levels on the structure,transmittance,and luminescence properties were systematically investigated.These transparent ceramics have average grain sizes of 10–16μm,clean grain boundaries,and excellent transmittance up to 83.4%at 800 nm.Under the excitation of 460 nm,three obvious emission peaks appear at 533,590,and 745 nm,which can be assigned to the transition 5 d→4 f of Ce^3+and 4 T1→6 A1 of Mn^2+.Thus,the Mn^2+–Si4+pairs can effectively modulate the emission spectrum by compensating broad orange-red and red spectrum component to yield high quality warm white light.After the optimized YAG:Ce,Mn transparent ceramic packaged with blue light-emitting diode(LED)chips,correlated color temperature(CCT)as low as 3723 K and luminous efficiency(LE)as high as 96.54 lm/W were achieved,implying a very promising candidate for application in white light-emitting diodes(WLEDs)industry.
文摘Metasurfaces, two-dimensional equivalents of metamaterials, are engineered surfaces consisting of deep subwavelength features that have full control of the electromagnetic waves. Metasurfaces are not only being applied to the current de-vices throughout the electromagnetic spectrum from microwave to optics but also inspiring many new thrilling applica-tions such as programmable on-demand optics and photonics in future. In order to overcome the limits imposed by pas-sive metasurfaces, extensive researches have been put on utilizing different materials and mechanisms to design active metasurfaces. In this paper, we review the recent progress in tunable and reconfigurable metasurfaces and metadevicesthrough the different active materials deployed together with the different control mechanisms including electrical, ther-mal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.
基金supported by the National Natural Science Foundation of China (No. 50902092 and 51102164)Science and Technology Commission of Shanghai Municipality (No. 1052nm06800 and 1052nm02000)+1 种基金Shanghai Pujiang Program (No. 11PJD011)the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning
文摘Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties.With excellent electrical conductivity of 6000 S/cm, which is independent on chirality, graphene is a promising material for high-performance nanoelectronics, transparent conductor, as well as polymer composites. On account of its Young's Modulus of 1 TPa and ultimate strength of 130 GPa, isolated graphene sheet is considered to be among the strongest materials ever measured. Comparable with the single-walled carbon nanotube bundle,graphene has a thermal conductivity of 5000 W/(m·K), which suggests a potential application of graphene in polymer matrix for improving thermal properties of the graphene/polymer composite. Furthermore, graphene exhibits a very high surface area, up to a value of 2630 m^2/g. All of these outstanding properties suggest a wide application for this nanometer-thick, two-dimensional carbon material. This review article presents an overview of the significant advancement in graphene research: preparation, functionalization as well as the properties of graphene will be discussed. In addition, the feasibility and potential applications of graphene in areas, such as sensors, nanoelectronics and nanocomposites materials, will also be reviewed.
