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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Slot-coupled perforated dielectric resonator ESPAR for X-band applications
摘要： A better understanding of the degradation modes and rates for photovoltaic (PV) modules is necessary to optimize and extend the lifetime of these modules. Lifetime and degradation science (L&DS) is used to understand degradation modes, mechanisms and rates of materials, components and systems to predict lifetime of PV modules. A PV module lifetime and degradation science (PVM L&DS) model is an essential component to predict lifetime and mitigate degradation of PV modules using reproducible open data science. Previously published accelerated testing data from Underwriter Laboratories on PV modules with fluorinated polyester backsheets, which included eight modules that were exposed up to 4000 hrs of damp heat (85% relative humidity at 85 ?C) and eight exposed up to 4000 hrs of ultraviolet light (80 W/m2 of 280–400 nm wavelengths at 60 ?C) (UV preconditioning) were used to determine statistically significant relationships between the applied stresses and measured responses. There were 15 different variables tracking aspects of system performance, degradation mechanisms, component metrics and time. Modules were analyzed for three system performance metrics (fill factor, peak power, and wet insulation). The results were statistically analyzed to identify variable transformations, statistically significant relationships (SSRs) and to develop the PVM L&DS model informed by a generalization of structural equation modeling techniques. The SSRs and significant model coefficients, combined with domain analytics, incorporating materials science, chemistry, and physics expertise, produced a pathway diagram ranking the variables’ impact on the system performance, which were iteratively examined using sound statistical analysis and diagnostics. The SSRs determined from the damp heat exposure for the system response of Pmax corresponded to the degradation pathway of polyester terephthalate (PET) and ethylene vinyl acetate (EVA) hydrolysis. A linear change point for the damp heat exposure with the system response of Pmax was determined to be 1890 hrs. The UV preconditioning exposure did not induce sufficient degradation shown by the quality of the R2 values for many of the best fitting models. This exemplifies the development of a methodology to determine rank ordered lifetime and degradation pathways present in modules and their effects on module performance over lifetime.
关键词： statistical analytics,lifetime and degradation science,Photovoltaics,structural equation modeling
更新于2025-09-19 17:13:59
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1.2: <i>Invited Paper:</i> Dynamic threshold voltage compensation IGZO‐GOA circuit for AMOLED display
摘要： A dual-gate amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) has been proposed and designed in this work. Based on this specific structure, a technologically advanced external Vth compensation system, where Vth can be controllable by an external DC signal source, has been developed for gate driver on array (GOA). Subsequently, the working mode of this circuit was introduced. Moreover, detailed simulation has been performed to study the appropriate process window. Finally, the proposed GOA circuit exhibited stable high-voltage output pulse, meanwhile, the lifetime showed an significant improvement with the utilization of the external Vth compensation system. It should be also mentioned that a wide pulse of 3.6ms has been obtained to sense Vth of driving TFTs in pixel circuits.
关键词： GOA,external compensation system,wide pulse,lifetime,a-IGZO
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Control of Texture Size on As-Cut Crystalline Silicon by Microparticle-Assisted Texturing (MPAT) Process
摘要： The texture size on as-cut crystalline silicon (c-Si) is drastically reduced from ~22 μm to <2.7 μm when mixing glass microparticles with conventional alkaline texturing solutions. The processing time and c-Si loss are considerably reduced from >15 to ~3 min and from >8 to 2 μm (for one side), respectively. Thus, this process is applicable to very thin c-Si. High-quality surface passivation with the effective minority carrier lifetimes >7 ms, corresponding to surface recombination velocity of 0.38 cm/s was possible. After anti-reflection coating, the reflectivity ~0.4% at 600nm, and <2% in wide wavelength 450?950nm was achieved on this new texture.
关键词： photovoltaic cells,light trapping,charge carrier lifetime,etching,cleaning,silicon,chemical processes
更新于2025-09-19 17:13:59
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Effect of Si substrate modification on improving the crystalline quality, optical and electrical properties of thermally-evaporated BaSi2 thin-films for solar cell applications
摘要： We have grown orthorhombic barium disilicide (BaSi2) thin-films on modified silicon (Si) substrates by a thermal evaporation method. The surface modification of Si substrate was performed by a metal-assisted chemical etching method. The effects of etching time te on crystalline quality as well as optical and electrical properties of the BaSi2 films were investigated. The obtained results showed that substrate modification can enhance the crystalline quality and electrical properties; reduce the light reflection; and increase the absorption of the BaSi2 thin-films. The te of 8 s was chosen as the optimized condition for surface modification of Si substrate. The achieved inferred short-circuit current density, Hall mobility, and minority carrier lifetime of the BaSi2 film at te of 8 s were 38 mA/cm2, 273 cm2/Vs, and 2.3 μs, respectively. These results confirm that the BaSi2 thin-film evaporated on the modified Si substrate is a promising absorber for thin-film solar cell applications.
关键词： hall mobility,substrate modification,photoresponse,silicide semiconductor,Barium disilicide,minority carrier lifetime,optical property,thermal evaporation
更新于2025-09-19 17:13:59
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Influence of nonradiative Auger process in the lanthanide complexes lifetime near interfaces in organic light-emitting diode structures
摘要： The low efficiency of organic light-emitting diodes based on lanthanide complexes is generally attributed to the triplet-triplet annihilation processes in the regime of high concentration of excited states caused by their long lifetimes and optical losses near the interfaces of multilayer device structures. Despite the enormous effort to synthesize short-lived complexes and minimize the optical losses in the interfaces, it remains insufficient in understanding the exciton recombination processes that reduce the lifetime of these complexes. Herein, we investigated the influence of the exciton recombination processes on a Tb complex (Tb-C) lifetime in the regime of a highly excited state concentration as a function of the distance between the carrier layer and the interface by using a typical organic light-emitting diode structure. Our results show that a 10 nm-thick Alq3 layer decreases the exciton lifetime of the Tb-C, increasing approximately by 16 times the spontaneous emission decay rate of triplet exciton. The effects of interference and optical losses at the metallic interface contribute actively to the modulation of the emission intensity and lifetime decay. However, these effects alone do not explain the significant increase in the emission decay rate. The nonradiative Auger process at the Alq3/Tb-C interface seems to be largely accountable for the Tb-C lifetime reduction as the energy released by the terbium ion occurs by the excitation of an adjacent electron at higher energy. Furthermore, we propose a simple theoretical model to explain the observed effects. These results can provide a new approach to reduce the lanthanide complexes’ lifetime through the Auger electron process near the interface and thus improve the performance of organic light-emitting diodes.
关键词： exciton recombination,Auger process,organic light-emitting diodes,lifetime reduction,lanthanide complexes
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - In situ and ex situ Investigations of Oxygen, Light and Temperature Influence on Halide Perovskites: Absorption and Transport Properties
摘要： In this work multi-cations hybrid perovskite thin film properties were explored by characterization techniques that proved to be very powerful for inorganic thin films. In particular, we report the evolution of the ambipolar diffusion length under different environmental or thermal stresses by Steady State Photocarrier Grating, directly observing the effects of oxygen absorption/desorption onto the material electronic properties. Moreover, the effects of illumination on the absorption properties were investigated via Fourier Transform Photocurrent Spectroscopy, a technique that allows to access to weak absorptions (E<Eg).
关键词： charge carrier lifetime,photovoltaic cells,organic inorganic hybrid materials
更新于2025-09-19 17:13:59
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Suppression of device degradation mechanism by triphenylsilyl group substitution of the host for blue phosphorescent organic light-emitting diodes
摘要： The effect of triphenylsilyl group substitution in the host materials for blue phosphorescent organic light-emitting diodes was studied by synthesizing two hole transport type hosts with and without the triphenylsilyl group in the identical backbone structure. The two host materials were applied as the hosts of blue phosphorescent emitter and the comparison of the emission behavior of the two hosts revealed that the triphenylsilyl group suppressed triplet exciton quenching of the blue phosphorescent emitters. As a result, the blue host with the triphenylsilyl group showed improved device efficiency and extended device lifetime in the blue phosphorescent devices. The blue phosphorescent device with the triphenylsilyl group substituted host showed improved external quantum efficiency and elongated device lifetime compared to the triphenylsilyl free host based device. The bulky triphenylsilyl group was effective to extend the device lifetime of the blue phosphorescent device through reduced triplet exciton induced annihilation.
关键词： host,blue device,device lifetime,phosphorescent host
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Optical Parametric Oscillator Based Differential Absorption Lidar for Tropospheric Methane Concentration Measurement
摘要： If there is no reactive power exchange between a doubly fed induction generator (DFIG) and a grid, the various characteristics of the power converters in a DFIG wind turbine system cause the lifetime expectancy of a rotor-side converter (RSC) to be significantly less than that of a grid-side converter (GSC). In order to fulfill modern grid codes, over-excited reactive power injection will further reduce the lifetime of the RSC. In this paper, the additional stress of a power semiconductor due to the reactive power injection is first evaluated in terms of a modulation index and the current loading. Then, an optimized reactive power flow is proposed in the case where an over-excited reactive power support is applied with the joint compensation from both the RSC and the GSC. Finally, some experimental validations are performed at a downscale DFIG prototype. It is concluded that, among the different combined reactive power support strategies, the best scheme will tradeoff the lifetime between the GSC and the RSC.
关键词： thermal behavior,Consumed lifetime,reactive power,doubly fed induction generator (DFIG)
更新于2025-09-19 17:13:59
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SPR based optical fiber refractive index sensor using silver nanowire assisted CSMFC
摘要： In this letter, we propose a compensation method for organic light-emitting diode (OLED) degradation occurring in a digital driving scheme for active-matrix OLED displays. The proposed method, in which we are the first to propose, employs the modified stretched exponential decay (SED) model to characterize the OLED degradation and compensates for the associated luminance decrease; the lifetime of an OLED panel can thereby be extended. The OLED panel is fabricated using low-temperature poly-Si thin-film transistors, and measured to verify the modified SED model and the proposed compensation method. The measurement results show that the luminance degradation with and without the proposed method is 0.3% and 6%, 4% and 17.8%, and 7.4% and 30.4%, for red, green, and blue OLEDs, respectively. This measurement is taken after 40 h of operation under a 350 cd/m2 initial luminance. Accordingly, the proposed compensation method extends the lifetime of the OLED panel up to 72.5, 15.5, and 20.75 times longer in red, green, and blue OLEDs, respectively, compared with the conventional method.
关键词： OLED degradation,AMOLED,compensation,lifetime extension of AMOLED,stretched exponential decay model,digital driving
更新于2025-09-19 17:13:59
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1: Challenges of TFT Technology for AMOLED Display
摘要： Active-matrix organic light emitting diodes (AMOLEDs) has been widely adopted in small-, medium- and large-sized displays for applications such as smartphones, automotive dashboards, smart wearables, VR/AR, etc. From the point of view of mass production, AMOLEDs still suffer from the challenges of the TFT backplane to stringent and sometimes conflicting property requirements for TFTs. Based on a review of the technological trends for AMOLED displays, we will herein systematically analyze the challenges for TFT properties, in terms of their relationships with product performance issues, such as lifetime, mura, and image sticking. It was found that minimizing the Ids-Vds slope in the saturation region contributes to improvement in lifetime of AMOLEDs. Incorporating an oxidative plasma treatment before gate-insulator (GI) deposition, a GI annealing process, and a use of a double-layer (SiO2/SiN) GI are helpful to reduce the trap density in oxide layer and at the poly-Si/GI interface, and help improve short-time image-sticking.
关键词： AMOLED,image sticking,TFT,lifetime,mura
更新于2025-09-19 17:13:59