AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layer...AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layers(EBLs).To overcome these limitations,we propose an EBL-free DUV LD design incor-porating a 1-nm undoped Al_(0.8)Ga_(0.2)N thin strip layer after the last quantum barrier.Using PICS3D simula-tions,we evaluate the optical and electrical characteristics.Results show a significant increase in effective electron barrier height(from 158.2 meV to 420.7 meV)and a reduction in hole barrier height(from 149.2 meV to 62.8 meV),which enhance hole injection and reduce electron leakage.The optimized structure(LD3)achieves a 14%increase in output power,improved slope efficiency(1.85 W/A),and lower threshold current.This design also reduces the quantum confined Stark effect and forms dual hole accumulation regions,im-proving recombination efficiency.展开更多
Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)g...Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)great potential for high-quality color displays with a wide color gamut and pure color emission.Although laboratory-scale Pe LEDs have achieved neartheoretical efficiencies,challenges such as achieving uniform large-area films,improving material stability,and enhancing patterning precision remain barriers to commercialization.This review presents a systematic analysis of scalable manufacturing and precision patterning strategies for Pe LEDs,focusing on their applications in large-area lighting and full-color displays.Fabrication methods are categorized into film deposition techniques(spin-coating,blade-coating,and thermal evaporation)and patterning strategies,including top-down(photolithography,laser/e-beam lithography,and nanoimprinting)and bottom-up(patterned crystal growth,inkjet printing,and electrohydrodynamic jet printing)approaches.In this review,we discuss the advantages and limitations of each strategy,highlight current challenges,and outlook possible pathways towards scalable,high-performance Pe LEDs for advanced optoelectronic applications.展开更多
Electrodeposited organic light-emitting diode(OLED)technology requires a spin-coating-free hole-injection layer that simultaneously provides smooth surface morphology,stable energy levels,and compatibility with high-r...Electrodeposited organic light-emitting diode(OLED)technology requires a spin-coating-free hole-injection layer that simultaneously provides smooth surface morphology,stable energy levels,and compatibility with high-resolution pixel architectures.In this study,electropolymerization of 3,4-ethylenedioxythiophene(EDOT)in poly(styrene sulfonate)(PSS-)surfactant-solubilized colloidal media is shown to afford poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)films with robust surface uniformity and stable energy levels suitable for application as hole-injection layers in OLEDs.Systematic investigation reveals that the hole-injection properties of these films are governed primarily by the colloidal chemistry of EDOT/PSS-surfactant-solubilized systems,rather than by conventional electrochemical parameters.This colloidal regulation modulates the film work function over a practically useful range.Incorporation of optimized films into OLEDs leads to enhanced hole injection and improved device performance,with external quantum efficiency increasing from 2.2%to 7.4%and minimal roll-off.Overall,this work demonstrates a feasible example of realizing spin-coating-free hole-injection layers,offering a potential direction for the development of electrodeposited injection layers for OLEDs.展开更多
To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polym...To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polymer light-emitting diodes(PLEDs).Herein,we introduced the steric carbazole-fluorene nanogrid into light-emitting diphenyl sulfone-based p-n polymer semiconductors(PG and PDG) via metal-free C-N coupling polymerization for the fabrication of deep-blue PLEDs.The steric,rigid and twisted configuration between nanogrid and diphenyl sulfone in PG and PDG present the unique characteristic of large steric hindrance interaction to suppress interchain aggregation in solid state.Due to the different length of electron-deficient diphenyl sulfone monomers,PG showed a deep-blue emission with a maximum peak at 428 nm but red-shifted to 480 nm for the PDG films.Interestingly,similar deep-blue emission behavior of PG in diluted non-polar solution and films suggested the extremely weak interchain aggregation.Finally,PLEDs based on PG are fabricated with a stable deep-blue emission of CIE(0.15,0.10),and corresponding EL spectral profile is also completely identical to PL ones of diluted solution,revealed the intrachain emission without obvious interchain excited state,confirmed effectiveness of the steric hindrance functionalization of nanogrid in p-n polymer semiconductor for deep-blue light-emitting organic optoelectronics.展开更多
Metal halide perovskites have emerged as highly promising candidates for the emissive layer in next-generation light-emitting diodes(LEDs)due to their narrow emission linewidths,high photoluminescence quantum yields,a...Metal halide perovskites have emerged as highly promising candidates for the emissive layer in next-generation light-emitting diodes(LEDs)due to their narrow emission linewidths,high photoluminescence quantum yields,and tunable emission wavelengths.Achieving high-performance perovskite LEDs(Pe LEDs)requires the emissive layer to possess efficient radiative recombination,low defect density,minimal ion mobility,and effective carrier confinement.Perovskite/perovskite heterostructure(PPHS)offers a compelling approach for engineering emissive layers with these desired attributes,owing to their ability to passivate surface defects,tailor bandgaps,and suppress ion migration.Pe LEDs based on PPHS have demonstrated superior performance compared to single-phase devices,particularly in terms of external quantum efficiency and operational stability.This review provides a comprehensive overview of the typical PPHS architectures applied in Pe LEDs,including vertical,lateral,and bulk configurations.We discuss representative fabrication strategies and the associated optoelectronic properties of these heterostructures,highlighting the mechanisms by which they enhance device efficiency and stability.Finally,we explore the remaining challenges and prospects for the application of PPHS in Pe LEDs and other luminescent technologies.展开更多
Perovskite quantum dot light-emitting diodes(Pe-QLEDs)have shown immense application potential in display and lighting fields due to their narrow full-width at half maximum(FWHM)and high photoluminescence quantum yiel...Perovskite quantum dot light-emitting diodes(Pe-QLEDs)have shown immense application potential in display and lighting fields due to their narrow full-width at half maximum(FWHM)and high photoluminescence quantum yield(PLQY).Despite significant advancements in their performance,challenges such as defects and ion migration still hinder their long-term stability and operational efficiency.To address these issues,various optimization strategies,including ligand engineering,interface passivation,and self-assembly strategy,are being actively researched.This review focuses on the synthesis methods,challenges and optimization of perovskite quantum dots,which are critical for the commercialization and large-scale production of high-performance and stable Pe-QLEDs.展开更多
The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investiga...The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investigates how quantum confinement governs the charge transport,exciton dynamics,and emission efficiency in QD-LEDs,using CsPbI_(3) QDs as a model system.By systematically varying QD sizes,we reveal size-dependent trade-offs in LED performance,such as enhanced efficiency for smaller QDs but increased brightness and stability for larger QDs under high current densities.Our findings offer critical insights into the design of high-performance QD-LEDs,paving the way for scalable and energy-efficient optoelectronic devices.展开更多
Stimulated emission and lasing of GaN-based laser diodes(LDs)were reported at 1995[1]and 1996[2],right after the breakthrough of p-type doping[3−5],material quality[6]and the invention of high-brightness GaN-based LED...Stimulated emission and lasing of GaN-based laser diodes(LDs)were reported at 1995[1]and 1996[2],right after the breakthrough of p-type doping[3−5],material quality[6]and the invention of high-brightness GaN-based LEDs[7,8].However,it took much longer time for GaN-based LDs to achieve high power,high wall plug efficiency,and long lifetime.Until 2019,Nichia reported blue LDs with these performances[9],which open wide applications with GaN-based blue LDs.展开更多
Background Plant tissue culture has emerged as a tool for improving cotton propagation and genetics,but recalcitrance nature of cotton makes it difficult to develop in vitro regeneration.Cotton’s recalcitrance is inf...Background Plant tissue culture has emerged as a tool for improving cotton propagation and genetics,but recalcitrance nature of cotton makes it difficult to develop in vitro regeneration.Cotton’s recalcitrance is influenced by genotype,explant type,and environmental conditions.To overcome these issues,this study uses different machine learning-based predictive models by employing multiple input factors.Cotyledonary node explants of two commercial cotton cultivars(STN-468 and GSN-12)were isolated from 7–8 days old seedlings,preconditioned with 5,10,and 20 mg·L^(-1) kinetin(KIN)for 10 days.Thereafter,explants were postconditioned on full Murashige and Skoog(MS),1/2MS,1/4MS,and full MS+0.05 mg·L^(-1) KIN,cultured in growth room enlightened with red and blue light-emitting diodes(LED)combination.Statistical analysis(analysis of variance,regression analysis)was employed to assess the impact of different treatments on shoot regeneration,with artificial intelligence(AI)models used for confirming the findings.Results GSN-12 exhibited superior shoot regeneration potential compared with STN-468,with an average of 4.99 shoots per explant versus 3.97.Optimal results were achieved with 5 mg·L^(-1) KIN preconditioning,1/4MS postconditioning,and 80%red LED,with maximum of 7.75 shoot count for GSN-12 under these conditions;while STN-468 reached 6.00 shoots under the conditions of 10 mg·L^(-1) KIN preconditioning,MS with 0.05 mg·L^(-1) KIN(postconditioning)and 75.0%red LED.Rooting was successfully achieved with naphthalene acetic acid and activated charcoal.Additionally,three different powerful AI-based models,namely,extreme gradient boost(XGBoost),random forest(RF),and the artificial neural network-based multilayer perceptron(MLP)regression models validated the findings.Conclusion GSN-12 outperformed STN-468 with optimal results from 5 mg·L^(-1) KIN+1/4MS+80%red LED.Application of machine learning-based prediction models to optimize cotton tissue culture protocols for shoot regeneration is helpful to improve cotton regeneration efficiency.展开更多
The packaging quality of coaxial laser diodes(CLDs)plays a pivotal role in determining their optical performance and long-term reliability.As the core packaging process,high-precision laser welding requires precise co...The packaging quality of coaxial laser diodes(CLDs)plays a pivotal role in determining their optical performance and long-term reliability.As the core packaging process,high-precision laser welding requires precise control of process parameters to suppress optical power loss.However,the complex nonlinear relationship between welding parameters and optical power loss renders traditional trial-and-error methods inefficient and imprecise.To address this challenge,a physics-informed(PI)and data-driven collaboration approach for welding parameter optimization is proposed.First,thermal-fluid-solid coupling finite element method(FEM)was employed to quantify the sensitivity of welding parameters to physical characteristics,including residual stress.This analysis facilitated the identification of critical factors contributing to optical power loss.Subsequently,a Gaussian process regression(GPR)model incorporating finite element simulation prior knowledge was constructed based on the selected features.By introducing physics-informed kernel(PIK)functions,stress distribution patterns were embedded into the prediction model,achieving high-precision optical power loss prediction.Finally,a Bayesian optimization(BO)algorithm with an adaptive sampling strategy was implemented for efficient parameter space exploration.Experimental results demonstrate that the proposedmethod effectively establishes explicit physical correlations between welding parameters and optical power loss.The optimized welding parameters reduced optical power loss by 34.1%,providing theoretical guidance and technical support for reliable CLD packaging.展开更多
A binary-mixed electron transport layer(ETL)has been reported for constructing solution-processable near-infrared organic light-emitting diodes(NIR OLEDs).Relative to the single-component ETL,the binarymixed ETL compo...A binary-mixed electron transport layer(ETL)has been reported for constructing solution-processable near-infrared organic light-emitting diodes(NIR OLEDs).Relative to the single-component ETL,the binarymixed ETL composed of PDINN:TPBi can enhance the carrier transport capacity,reduce device impedance,and weaken fiuorescence quenching of the emitting layer.By carefully selecting an appropriate luminescent material Y5(a nonfullerene electron acceptor in organic solar cells)and precisely fine-tuning the molecular aggregation in active layer using a mixed solvent,the morphology is optimized and luminescence performance is enhanced,resulting in efficient NIR OLEDs with an emission peak at 890 nm.The experiment showcases a Y5-based near-infrared OLED with a maximum radiance of 34.9 W sr^(-1)m^(-2)and a maximum external quantum efficiency of 0.50%,which is among the highest values reported for nondoped fiuorescent NIR OLEDs with an emission peak over 850 nm.展开更多
GaN diodes for high energy(64.8 MeV)proton detection were fabricated and investigated.A comparison of the performance of GaN diodes with different structures is presented,with a focus on sapphire and on GaN substrates...GaN diodes for high energy(64.8 MeV)proton detection were fabricated and investigated.A comparison of the performance of GaN diodes with different structures is presented,with a focus on sapphire and on GaN substrates,Schottky and pin diodes,and different active layer thicknesses.Pin diodes fabricated on a sapphire substrate are the best choice for a GaN proton detector working at 0 V bias.They are sensitive(minimum detectable proton beam<1 pA/cm^(2)),linear as a function of proton current and fast(<1 s).High proton current sensitivity and high spatial resolution of GaN diodes can be exploited in the future for proton imaging of patients in proton therapy.展开更多
Triphenylamine(TPA)is the most promising donor fragment for the construction of long-wavelength thermally activated delayed fluorescence(TADF)emitters owing to its suitable dihedral angle that could enhance radiative ...Triphenylamine(TPA)is the most promising donor fragment for the construction of long-wavelength thermally activated delayed fluorescence(TADF)emitters owing to its suitable dihedral angle that could enhance radiative decay to compete with the serious non-radiative decay.However,the moderate electron-donating capacity of TPA seriously limits the selection of acceptor for constructing longwavelength TADF emitters with narrow bandgaps.To address this issue,in this work,the peripheral benzene of TPA was replaced with 1,4-benzodioxane and anisole to obtain two new electrondonating units N-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-N-phenyl-2,3-dihydrobenzo[b][1,4]dioxin-6-amine(TPADBO,−5.02 eV)and 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline(TPAMO,−5.00 eV),which possess much shallower highest occupied molecule orbital(HOMO)energy levels than the prototype TPA(−5.33 eV).Based on TPA and the modified TPA donor fragments,three TADF emitters were designed and synthesized,namely Py-TPA,Py-TPADBO and Py-TPAMO,with the same acceptor fragment 12-(2,6-diisopropylphenyl)pyrido[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline(Py).Among them,Py-TPAMO exhibits the highest photoluminescence quantum yield of 78.4%and the smallest singlet-triplet energy gap,which is because the introduction of anisole does not cause significant molecule deformation for the excited Py-TPAMO.And Py-TPAMO-based OLEDs successfully realize a maximum external quantum efficiency of 25.5%with the emission peak at 605 nm.This work provides a series of candidate of donor fragments for the development of efficient long-wavelength TADF emitters.展开更多
Colloidal quantum dots(CQDs)are highly regarded for their outstanding photovoltaic characteristics,including excellent color purity,stability,high photoluminescence quantum yield(PLQY),narrow emission spectra,and ease...Colloidal quantum dots(CQDs)are highly regarded for their outstanding photovoltaic characteristics,including excellent color purity,stability,high photoluminescence quantum yield(PLQY),narrow emission spectra,and ease of solution processing.Despite significant progress in quantum dot light-emitting diodes(QLEDs)technology since its inception in 1994,blue QLEDs still fall short in efficiency and lifespan compared to red and green versions.The toxicity concerns associated with Cd/Pb-based quantum dots(QDs)have spurred the development of heavy-metal-free alternatives,such as groupⅡ−Ⅵ(e.g.,ZnSe-based QDs),groupⅢ−Ⅴ(e.g.,InP,GaN QDs),and carbon dots(CDs).In this review,we discuss the key properties and development history of quantum dots(QDs),various synthesis approaches,the role of surface ligands,and important considerations in developing core/shell(C/S)structured QDs.Additionally,we provide an outlook on the challenges and future directions for blue QLEDs.展开更多
A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and c...A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed.展开更多
GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new struc...GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new structure for GaAs PIN diodes is proposed and the fabrication process is described. GaAs PIN diodes with an on-state resistance of 〈2. 2Ω and off-state capacitance -〈20fF in the range of 100MHz to 12.1GHz are obtained.展开更多
Material growth and device fabrication of the first 1.3μm quantum well （QW） edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy （MBE） growth conditions and the...Material growth and device fabrication of the first 1.3μm quantum well （QW） edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy （MBE） growth conditions and the tuning of the indium and nitrogen composition of the GalnNAs QWs, the emission wavelengths of the QWs can be tuned to 1.3μm. Ridge geometry waveguide laser diodes are fabricated. The lasing wavelength is 1.3μm under continuous current injection at room temperature with threshold current of 1kA/cm^2 for the laser diode structures with the cleaved facet mirrors. The output light power over 30mW is obtained.展开更多
A novel equivalent circuit model for a GaAs PIN diode is presented based on physical analysis. The diode is divided into three parts： the p^＋ n^- junction, the i-layer, and the n^- n^＋ junction, which are modeled s...A novel equivalent circuit model for a GaAs PIN diode is presented based on physical analysis. The diode is divided into three parts： the p^＋ n^- junction, the i-layer, and the n^- n^＋ junction, which are modeled separately. The entire model is then formed by combining the three sub-models. In this way, the model＇s accuracy is greatly enhanced. Furthermore, the corresponding parameter extraction method is easy, requiring no rigorous experiment or measurement. To validate this newly proposed model,fifteen groups of diodes are fabricated. Measurement shows that the model exactly represents behavior of GaAs PIN diodes under both forward and reversely biased conditions.展开更多
The 808nm laser diodes with a broad waveguide are designed and fabricated.The thickness of the Al_ 0.35 - Ga_ 0.65 As waveguide is increased to 0.9μm.In order to suppress the super modes,the thickness of the A...The 808nm laser diodes with a broad waveguide are designed and fabricated.The thickness of the Al_ 0.35 - Ga_ 0.65 As waveguide is increased to 0.9μm.In order to suppress the super modes,the thickness of the Al_ 0.55 Ga_ 0.45 As cladding layers is reduced to only 0.7μm while keeping the transverse radiation losses of the fundamental mode below 0.2cm -1 .The structures are grown by metal organic chemical vapour deposition.The devices show excellent performances.The maximum output power of 10.2W in the 100μm broad-area laser diodes is obtained.展开更多
A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,an...A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,and a two stage ring VCO.The principle of this VCO is demonstrated and further the phase noise is discussed in detail.The fabrication of prototype is demonstrated using 0 25μm single poly five metal N well salicide CMOS digital process.The reports show that the novel VCO is can generate quadrature LO signals with a tuning range of more than 300MHz as well as the phase noise--104 33dBc/Hz at 600KHz offset at 2 41GHz (when measuring only one port of differential outputs).In addition,this VCO can work in low power supply voltage and dissipate low power,thus it can be used in many integrated transceivers.展开更多
文摘AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layers(EBLs).To overcome these limitations,we propose an EBL-free DUV LD design incor-porating a 1-nm undoped Al_(0.8)Ga_(0.2)N thin strip layer after the last quantum barrier.Using PICS3D simula-tions,we evaluate the optical and electrical characteristics.Results show a significant increase in effective electron barrier height(from 158.2 meV to 420.7 meV)and a reduction in hole barrier height(from 149.2 meV to 62.8 meV),which enhance hole injection and reduce electron leakage.The optimized structure(LD3)achieves a 14%increase in output power,improved slope efficiency(1.85 W/A),and lower threshold current.This design also reduces the quantum confined Stark effect and forms dual hole accumulation regions,im-proving recombination efficiency.
基金supported by 14th Five-Year Plan Key R&D Plan,Ministry of Science and Technology of the People’s Republic of China,2024YFB3409002National Natural Science Foundation of China,12302142+4 种基金HKUSTHKUST(GZ)Collaborative Research Scheme,G035Yangcheng Scholars Research Project-Leading Talent Training Project,2024312156Guangzhou-HKUST(GZ)Joint Funding Scheme,2023A03J0157Guangzhou Basic and Applied Basic Research Project,2024A04J4765Shenzhen Basic Research Project,JCYJ20220530114417040。
文摘Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)great potential for high-quality color displays with a wide color gamut and pure color emission.Although laboratory-scale Pe LEDs have achieved neartheoretical efficiencies,challenges such as achieving uniform large-area films,improving material stability,and enhancing patterning precision remain barriers to commercialization.This review presents a systematic analysis of scalable manufacturing and precision patterning strategies for Pe LEDs,focusing on their applications in large-area lighting and full-color displays.Fabrication methods are categorized into film deposition techniques(spin-coating,blade-coating,and thermal evaporation)and patterning strategies,including top-down(photolithography,laser/e-beam lithography,and nanoimprinting)and bottom-up(patterned crystal growth,inkjet printing,and electrohydrodynamic jet printing)approaches.In this review,we discuss the advantages and limitations of each strategy,highlight current challenges,and outlook possible pathways towards scalable,high-performance Pe LEDs for advanced optoelectronic applications.
基金supported by the National Key R&D Program of China(No.2020YFA0714604)the Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(No.2023B1212060003)+1 种基金the SSL Sci-tech Commissioner Program(No.20234383-01KCJ-G)the National Natural Science Foundation of China(No.92463310)。
文摘Electrodeposited organic light-emitting diode(OLED)technology requires a spin-coating-free hole-injection layer that simultaneously provides smooth surface morphology,stable energy levels,and compatibility with high-resolution pixel architectures.In this study,electropolymerization of 3,4-ethylenedioxythiophene(EDOT)in poly(styrene sulfonate)(PSS-)surfactant-solubilized colloidal media is shown to afford poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)films with robust surface uniformity and stable energy levels suitable for application as hole-injection layers in OLEDs.Systematic investigation reveals that the hole-injection properties of these films are governed primarily by the colloidal chemistry of EDOT/PSS-surfactant-solubilized systems,rather than by conventional electrochemical parameters.This colloidal regulation modulates the film work function over a practically useful range.Incorporation of optimized films into OLEDs leads to enhanced hole injection and improved device performance,with external quantum efficiency increasing from 2.2%to 7.4%and minimal roll-off.Overall,this work demonstrates a feasible example of realizing spin-coating-free hole-injection layers,offering a potential direction for the development of electrodeposited injection layers for OLEDs.
基金the support from the Jiangsu Provincial Senior Talent Program (Dengfeng,Jiangsu University)the support from the National Key R&D Program of China (No.2024YFB3612600)+3 种基金the National Natural Science Foundation of China (Nos.22275098,62288102)Basic Research Program of Jiangsu (No.BK20243057)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications (No.NY222097)the National Natural Science Foundation of China (No.62205035)。
文摘To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polymer light-emitting diodes(PLEDs).Herein,we introduced the steric carbazole-fluorene nanogrid into light-emitting diphenyl sulfone-based p-n polymer semiconductors(PG and PDG) via metal-free C-N coupling polymerization for the fabrication of deep-blue PLEDs.The steric,rigid and twisted configuration between nanogrid and diphenyl sulfone in PG and PDG present the unique characteristic of large steric hindrance interaction to suppress interchain aggregation in solid state.Due to the different length of electron-deficient diphenyl sulfone monomers,PG showed a deep-blue emission with a maximum peak at 428 nm but red-shifted to 480 nm for the PDG films.Interestingly,similar deep-blue emission behavior of PG in diluted non-polar solution and films suggested the extremely weak interchain aggregation.Finally,PLEDs based on PG are fabricated with a stable deep-blue emission of CIE(0.15,0.10),and corresponding EL spectral profile is also completely identical to PL ones of diluted solution,revealed the intrachain emission without obvious interchain excited state,confirmed effectiveness of the steric hindrance functionalization of nanogrid in p-n polymer semiconductor for deep-blue light-emitting organic optoelectronics.
基金supported by the Advanced Talents Incubation Program of Hebei University(No.521100224235)the National Natural Science Foundation of China(No.52503363)the Natural Science Foundation of Hebei Province(No.E2025201009)。
文摘Metal halide perovskites have emerged as highly promising candidates for the emissive layer in next-generation light-emitting diodes(LEDs)due to their narrow emission linewidths,high photoluminescence quantum yields,and tunable emission wavelengths.Achieving high-performance perovskite LEDs(Pe LEDs)requires the emissive layer to possess efficient radiative recombination,low defect density,minimal ion mobility,and effective carrier confinement.Perovskite/perovskite heterostructure(PPHS)offers a compelling approach for engineering emissive layers with these desired attributes,owing to their ability to passivate surface defects,tailor bandgaps,and suppress ion migration.Pe LEDs based on PPHS have demonstrated superior performance compared to single-phase devices,particularly in terms of external quantum efficiency and operational stability.This review provides a comprehensive overview of the typical PPHS architectures applied in Pe LEDs,including vertical,lateral,and bulk configurations.We discuss representative fabrication strategies and the associated optoelectronic properties of these heterostructures,highlighting the mechanisms by which they enhance device efficiency and stability.Finally,we explore the remaining challenges and prospects for the application of PPHS in Pe LEDs and other luminescent technologies.
文摘Perovskite quantum dot light-emitting diodes(Pe-QLEDs)have shown immense application potential in display and lighting fields due to their narrow full-width at half maximum(FWHM)and high photoluminescence quantum yield(PLQY).Despite significant advancements in their performance,challenges such as defects and ion migration still hinder their long-term stability and operational efficiency.To address these issues,various optimization strategies,including ligand engineering,interface passivation,and self-assembly strategy,are being actively researched.This review focuses on the synthesis methods,challenges and optimization of perovskite quantum dots,which are critical for the commercialization and large-scale production of high-performance and stable Pe-QLEDs.
基金support from the National Key Research and Development Program of China(2024YFA1207700)National Natural Science Foundation of China(52072141,52102170).
文摘The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investigates how quantum confinement governs the charge transport,exciton dynamics,and emission efficiency in QD-LEDs,using CsPbI_(3) QDs as a model system.By systematically varying QD sizes,we reveal size-dependent trade-offs in LED performance,such as enhanced efficiency for smaller QDs but increased brightness and stability for larger QDs under high current densities.Our findings offer critical insights into the design of high-performance QD-LEDs,paving the way for scalable and energy-efficient optoelectronic devices.
基金supported by the Natural Science Foundation of Jiangsu Province(Grant.BK20232042).
文摘Stimulated emission and lasing of GaN-based laser diodes(LDs)were reported at 1995[1]and 1996[2],right after the breakthrough of p-type doping[3−5],material quality[6]and the invention of high-brightness GaN-based LEDs[7,8].However,it took much longer time for GaN-based LDs to achieve high power,high wall plug efficiency,and long lifetime.Until 2019,Nichia reported blue LDs with these performances[9],which open wide applications with GaN-based blue LDs.
文摘Background Plant tissue culture has emerged as a tool for improving cotton propagation and genetics,but recalcitrance nature of cotton makes it difficult to develop in vitro regeneration.Cotton’s recalcitrance is influenced by genotype,explant type,and environmental conditions.To overcome these issues,this study uses different machine learning-based predictive models by employing multiple input factors.Cotyledonary node explants of two commercial cotton cultivars(STN-468 and GSN-12)were isolated from 7–8 days old seedlings,preconditioned with 5,10,and 20 mg·L^(-1) kinetin(KIN)for 10 days.Thereafter,explants were postconditioned on full Murashige and Skoog(MS),1/2MS,1/4MS,and full MS+0.05 mg·L^(-1) KIN,cultured in growth room enlightened with red and blue light-emitting diodes(LED)combination.Statistical analysis(analysis of variance,regression analysis)was employed to assess the impact of different treatments on shoot regeneration,with artificial intelligence(AI)models used for confirming the findings.Results GSN-12 exhibited superior shoot regeneration potential compared with STN-468,with an average of 4.99 shoots per explant versus 3.97.Optimal results were achieved with 5 mg·L^(-1) KIN preconditioning,1/4MS postconditioning,and 80%red LED,with maximum of 7.75 shoot count for GSN-12 under these conditions;while STN-468 reached 6.00 shoots under the conditions of 10 mg·L^(-1) KIN preconditioning,MS with 0.05 mg·L^(-1) KIN(postconditioning)and 75.0%red LED.Rooting was successfully achieved with naphthalene acetic acid and activated charcoal.Additionally,three different powerful AI-based models,namely,extreme gradient boost(XGBoost),random forest(RF),and the artificial neural network-based multilayer perceptron(MLP)regression models validated the findings.Conclusion GSN-12 outperformed STN-468 with optimal results from 5 mg·L^(-1) KIN+1/4MS+80%red LED.Application of machine learning-based prediction models to optimize cotton tissue culture protocols for shoot regeneration is helpful to improve cotton regeneration efficiency.
基金funded by the National Key R&D Program of China,Grant No.2024YFF0504904.
文摘The packaging quality of coaxial laser diodes(CLDs)plays a pivotal role in determining their optical performance and long-term reliability.As the core packaging process,high-precision laser welding requires precise control of process parameters to suppress optical power loss.However,the complex nonlinear relationship between welding parameters and optical power loss renders traditional trial-and-error methods inefficient and imprecise.To address this challenge,a physics-informed(PI)and data-driven collaboration approach for welding parameter optimization is proposed.First,thermal-fluid-solid coupling finite element method(FEM)was employed to quantify the sensitivity of welding parameters to physical characteristics,including residual stress.This analysis facilitated the identification of critical factors contributing to optical power loss.Subsequently,a Gaussian process regression(GPR)model incorporating finite element simulation prior knowledge was constructed based on the selected features.By introducing physics-informed kernel(PIK)functions,stress distribution patterns were embedded into the prediction model,achieving high-precision optical power loss prediction.Finally,a Bayesian optimization(BO)algorithm with an adaptive sampling strategy was implemented for efficient parameter space exploration.Experimental results demonstrate that the proposedmethod effectively establishes explicit physical correlations between welding parameters and optical power loss.The optimized welding parameters reduced optical power loss by 34.1%,providing theoretical guidance and technical support for reliable CLD packaging.
基金supported by the National Natural Science Foundation of China(No.51973020)Beijing Natural Science Foundation(No.2232052)。
文摘A binary-mixed electron transport layer(ETL)has been reported for constructing solution-processable near-infrared organic light-emitting diodes(NIR OLEDs).Relative to the single-component ETL,the binarymixed ETL composed of PDINN:TPBi can enhance the carrier transport capacity,reduce device impedance,and weaken fiuorescence quenching of the emitting layer.By carefully selecting an appropriate luminescent material Y5(a nonfullerene electron acceptor in organic solar cells)and precisely fine-tuning the molecular aggregation in active layer using a mixed solvent,the morphology is optimized and luminescence performance is enhanced,resulting in efficient NIR OLEDs with an emission peak at 890 nm.The experiment showcases a Y5-based near-infrared OLED with a maximum radiance of 34.9 W sr^(-1)m^(-2)and a maximum external quantum efficiency of 0.50%,which is among the highest values reported for nondoped fiuorescent NIR OLEDs with an emission peak over 850 nm.
基金support from MATRIX(ANR-22-CE92-0047)with financial support from ITMI Cancer of Aviesan within the framework of the 2021−2030 Cancer Control Strategy,on funds administrated by INSERM through the project NECTAR.Matilde Siviero acknowledges funding from the French−German University/Saarbrücken(contract CDOC-06-2022).
文摘GaN diodes for high energy(64.8 MeV)proton detection were fabricated and investigated.A comparison of the performance of GaN diodes with different structures is presented,with a focus on sapphire and on GaN substrates,Schottky and pin diodes,and different active layer thicknesses.Pin diodes fabricated on a sapphire substrate are the best choice for a GaN proton detector working at 0 V bias.They are sensitive(minimum detectable proton beam<1 pA/cm^(2)),linear as a function of proton current and fast(<1 s).High proton current sensitivity and high spatial resolution of GaN diodes can be exploited in the future for proton imaging of patients in proton therapy.
基金supported by the National Natural Science Foundation of China (Nos. 62222503, 52073040 and 52130304)the Sichuan Science and Technology Program (Nos. 2024NSFSC0012,2023NSFSC1973 and 2024NSFSC1446)+2 种基金the China Postdoctoral Science Foundation (Nos. 2023M740504 and GZC20230380)the Sichuan Provincial Human Resources and Social Security Department Programthe Collaborative Innovation Center of Suzhou Nano Science&Technology
文摘Triphenylamine(TPA)is the most promising donor fragment for the construction of long-wavelength thermally activated delayed fluorescence(TADF)emitters owing to its suitable dihedral angle that could enhance radiative decay to compete with the serious non-radiative decay.However,the moderate electron-donating capacity of TPA seriously limits the selection of acceptor for constructing longwavelength TADF emitters with narrow bandgaps.To address this issue,in this work,the peripheral benzene of TPA was replaced with 1,4-benzodioxane and anisole to obtain two new electrondonating units N-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-N-phenyl-2,3-dihydrobenzo[b][1,4]dioxin-6-amine(TPADBO,−5.02 eV)and 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline(TPAMO,−5.00 eV),which possess much shallower highest occupied molecule orbital(HOMO)energy levels than the prototype TPA(−5.33 eV).Based on TPA and the modified TPA donor fragments,three TADF emitters were designed and synthesized,namely Py-TPA,Py-TPADBO and Py-TPAMO,with the same acceptor fragment 12-(2,6-diisopropylphenyl)pyrido[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline(Py).Among them,Py-TPAMO exhibits the highest photoluminescence quantum yield of 78.4%and the smallest singlet-triplet energy gap,which is because the introduction of anisole does not cause significant molecule deformation for the excited Py-TPAMO.And Py-TPAMO-based OLEDs successfully realize a maximum external quantum efficiency of 25.5%with the emission peak at 605 nm.This work provides a series of candidate of donor fragments for the development of efficient long-wavelength TADF emitters.
基金supported by the National Key Research and Development Program of China(2024YFE0103600)the National Natural Science Foundation of China(NSFC)(62474119,62205230,and 62175171)Suzhou Key Laboratory of Functional Nano&Soft Materials,Collaborative Innovation Center of Suzhou Nano Science&Technology,the 111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and Devices.
文摘Colloidal quantum dots(CQDs)are highly regarded for their outstanding photovoltaic characteristics,including excellent color purity,stability,high photoluminescence quantum yield(PLQY),narrow emission spectra,and ease of solution processing.Despite significant progress in quantum dot light-emitting diodes(QLEDs)technology since its inception in 1994,blue QLEDs still fall short in efficiency and lifespan compared to red and green versions.The toxicity concerns associated with Cd/Pb-based quantum dots(QDs)have spurred the development of heavy-metal-free alternatives,such as groupⅡ−Ⅵ(e.g.,ZnSe-based QDs),groupⅢ−Ⅴ(e.g.,InP,GaN QDs),and carbon dots(CDs).In this review,we discuss the key properties and development history of quantum dots(QDs),various synthesis approaches,the role of surface ligands,and important considerations in developing core/shell(C/S)structured QDs.Additionally,we provide an outlook on the challenges and future directions for blue QLEDs.
文摘A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed.
文摘GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new structure for GaAs PIN diodes is proposed and the fabrication process is described. GaAs PIN diodes with an on-state resistance of 〈2. 2Ω and off-state capacitance -〈20fF in the range of 100MHz to 12.1GHz are obtained.
文摘Material growth and device fabrication of the first 1.3μm quantum well （QW） edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy （MBE） growth conditions and the tuning of the indium and nitrogen composition of the GalnNAs QWs, the emission wavelengths of the QWs can be tuned to 1.3μm. Ridge geometry waveguide laser diodes are fabricated. The lasing wavelength is 1.3μm under continuous current injection at room temperature with threshold current of 1kA/cm^2 for the laser diode structures with the cleaved facet mirrors. The output light power over 30mW is obtained.
文摘A novel equivalent circuit model for a GaAs PIN diode is presented based on physical analysis. The diode is divided into three parts： the p^＋ n^- junction, the i-layer, and the n^- n^＋ junction, which are modeled separately. The entire model is then formed by combining the three sub-models. In this way, the model＇s accuracy is greatly enhanced. Furthermore, the corresponding parameter extraction method is easy, requiring no rigorous experiment or measurement. To validate this newly proposed model,fifteen groups of diodes are fabricated. Measurement shows that the model exactly represents behavior of GaAs PIN diodes under both forward and reversely biased conditions.
文摘The 808nm laser diodes with a broad waveguide are designed and fabricated.The thickness of the Al_ 0.35 - Ga_ 0.65 As waveguide is increased to 0.9μm.In order to suppress the super modes,the thickness of the Al_ 0.55 Ga_ 0.45 As cladding layers is reduced to only 0.7μm while keeping the transverse radiation losses of the fundamental mode below 0.2cm -1 .The structures are grown by metal organic chemical vapour deposition.The devices show excellent performances.The maximum output power of 10.2W in the 100μm broad-area laser diodes is obtained.
文摘A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,and a two stage ring VCO.The principle of this VCO is demonstrated and further the phase noise is discussed in detail.The fabrication of prototype is demonstrated using 0 25μm single poly five metal N well salicide CMOS digital process.The reports show that the novel VCO is can generate quadrature LO signals with a tuning range of more than 300MHz as well as the phase noise--104 33dBc/Hz at 600KHz offset at 2 41GHz (when measuring only one port of differential outputs).In addition,this VCO can work in low power supply voltage and dissipate low power,thus it can be used in many integrated transceivers.
