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- spectral reconstruction
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Reprint of “Oxygen-plasma processed Spiro-OMeTAD toward high performance for perovskite solar cell”
摘要： Efficient perovskite solar cell was achieved using a small hole transport material, Spiro-OMeTAD, after oxygen plasma treatment. It was demonstrated that the plasma treatment of hole transport layer for the solids state perovskite solar cell was enhanced power conversion efficiency. Reason for enhancing the cell performance of solar cell was good match of homo energy level between perovskite and Spiro-OMeTAD. It leads to transfer well hole carrier at Active/HTL interface. This study obtained highly improved performance by a current density of 25.4 mA/cm2, an open-circuit voltage of 1.02 V, and a fill factor of 60.2%, which resulted showed above 15% of cell efficiency.
关键词： Perovskite solar cell,Oxygen plasma,Plasma treatment,Aging effect
更新于2025-09-16 10:30:52
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Photovoltaic Modules (Technology and Reliability) || 10. Accelerated aging tests
摘要： All environmental simulation tests which allow an accelerated analysis of material degradation processes through intensified environmental stress levels compared to real life can be summarized under the notion of accelerated aging tests. This type of test is especially useful for products with long service lifetimes, such as photovoltaic modules. As guarantees for PV modules cover up to 30 years of service life, accelerated aging tests are of high economic importance for PV modules manufacturers. As PV manufactures aim for utilizing materials which are both economically and technically suitable, accelerated aging tests on full PV modules as well as on separate materials and material combinations are necessary. It is in the interest of the customer as well the investor and the insurance that the product achieves the expected service life without major performance losses. The aim of accelerated aging tests is to achieve reliable results within a very short period of time and with minimum costs in order to keep pace with the rapid innovation cycles. In order to ensure the transferability of the testing result on real life performance, a specific adaptation of the test conditions to the specific materials and stress factors is indispensable. Otherwise, climatic conditions may be induced which either exceed or undermine those under standard operation, and this may subsequently lead to altered physical or chemical degradation processes. Thus, the processes which occur under standard operation should be accelerated but at the same time simulated as close to reality as possible.
关键词： photovoltaic modules,service life,environmental stress,material degradation,accelerated aging tests
更新于2025-09-16 10:30:52
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Fluorescence imaging analysis of depth‐dependent degradation in photovoltaic laminates: insights to the failure
摘要： Accurate evaluation of the reliability of photovoltaic (PV) packaging materials is critically important for the long‐term safe operation of modules. However, the complexity of the laminated systems due to their multilayered and multicomponent structures and diverse aging mechanisms makes a thorough system evaluation very challenging, especially when the degradation is non‐uniform through the thickness. In such a case, neither surface nor bulk measurements can present a clear picture of the degradation profile. In this study, fluorescence imaging was developed to visualize the degradation depth‐profiles of an aged laminated PV system. A glass/ethylene vinyl acetate (EVA) encapsulant/poly(ethylene terephthalate) (PET)‐PET‐EVA (PPE) backsheet laminate was weathered with the glass‐side facing an ultra-violet (UV) light source for 3840 h. Cross‐sectional fluorescence images revealed a non‐uniform distribution of degradation species across the thickness of the EVA encapsulant, providing greater insight into the mechanisms of degradation, which are unavailable by traditional bulk‐based methods. In addition, strong fluorescence emissions were observed from the two thin adhesive layers of the aged backsheet, indicating severe degradation of the adhesives and a potential for interlayer delamination. This method is further confirmed with other microscale characterization techniques. The changes in optical (yellowness index), chemical (oxidation, UV absorber concentration), mechanical (Derjaguin‐Muller‐Toporov modulus), and thermal (melting enthalpy) properties of the EVA encapsulant were found to be related to fluorescence profiles, following the attenuation of UV light. This study highlights that fluorescence imaging is a spatially‐resolved and sensitive method for rapid failure assessment and in‐depth mechanism study for complex PV‐laminated system.
关键词： modulus,depth profile,UV aging,photovoltaic laminates,yellowness index,fluorescence imaging,degradation
更新于2025-09-16 10:30:52
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Laser-Aided Enamel Conditioning: A Comparison of Microleakage Under Brackets Following Different Aging Procedures
摘要： Objective: To evaluate microleakage under the orthodontic adhesives applied following two version of erbium:yttrium aluminum garnet (Er:YAG) laser-aided enamel conditioning after thermal and thermomechanical simulators. Materials and Methods: A comparative analytical study based on metal braces bonded on the enamel of extracted teeth (n = 160) etched with acid, Er:YAG laser and Er:YAG laser with an X-Runner handpiece, and self-etch adhesives. An arch wire was ligatured to samples which were embedded in acrylic blocks by two with periodontal ligaments. The specimens were subdivided into two groups: those aged with thermal cycling and thermomechanical aging procedures. The samples were immersed in basic fuchsin solution (0.5%) for 24 h. Buccolingual sections were performed on the mesial and distal wings of the braces. The color penetration at the gingival and occlusal margins of the adhesive-bracket and enamel-adhesive was evaluated under a stereomicroscope. The median and mean values of microleakage in both groups were evaluated with Kruskal–Wallis and Mann–Whitney U tests (P < .05). Results: The highest microleakage was recorded in the gingival part of the samples aged with the thermomechanical aging procedure (P = .001). The amount of microleakage generally increased in the samples subjected to thermomechanical loading, but the only significant difference was recorded in the gingival part in each four different conditioning methods. Conclusion: Microleakage of the phosphoric acid-etched groups was recorded with lower values for both aging methods. Thermomechanical aging should be included to microleakage studies due to increased microleakage on gingival side for all etching groups.
关键词： thermomechanical aging,Chewing simulation in orthodontics,microleakage,X-Runner handpiece,Er:YAG Laser
更新于2025-09-16 10:30:52
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Study on light aging of anhydride-cured epoxy resin used for RGB LED packaging material
摘要： RGB LED is widely used in white light illumination and display fields due to its high luminous efficiency and full color display. However, the color drift will occur when RGB LED is used for a long time. In this paper, the luminous performance of RGB LED encapsulated by epoxy materials during longtime lighting and the aging mechanism of methyl hexahydrophthalic anhydride (MHHPA) cured diglycidyl ether of bisphenol-A (DGEBA) were studied by Array spectrometer, ATR-FTIR, XPS and quantum-chemistry calculation. Firstly, the analysis of the lumen maintenance and forward voltage of RGB LED lamps showed, the color drift might be attributed to the degradation of its epoxy materials caused by blue light. FTIR Spectroscopy showed that the aging of packaging materials mainly occurred on the surface of blue LED lamps, where active hydrogen of secondary and tertiary carbon might be oxidized to carbonyl groups due to O2 or peroxy groups in the air. And the aging of epoxy materials also might include the chain scission or the rearrangement reactions of C-O-Ph. XPS results further manifested the decrease of C-C group and increase of C-O and C=O group were mainly caused by the chain scission of C-C, C-O-Ph or the ester groups and the oxidation of active hydrogen. And several possible aging reactions were given from the analysis of ATR-FTIR and XPS characterization. The results of quantum-chemistry calculation indicated that C-O bond in C-O-Ph of DGEBA/MHHPA epoxy system was more easily to be broken down during blue light aging, which further verified the results of IR and XPS characterization.
关键词： quantum-chemistry calculation,epoxy resin,light aging,RGB LED
更新于2025-09-16 10:30:52
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A Pixel Circuit With Wide Data Voltage Range for OLEDoS Microdisplays With High Uniformity
摘要： A new pixel circuit is proposed for the realization of high resolution and high uniformity organic light-emitting diode on silicon (OLEDoS) microdisplays in this article. A compensation scheme is adopted to mitigate the influence of threshold voltage variation of the driving transistor on display uniformity. Furthermore, two coupling capacitors are used to reduce the voltage at the gate terminal of the driving transistor in order to extend the data voltage range. The performance of the proposed pixel circuit is verified in an industrial 0.18-μm CMOS process. Simulation results show that the data voltage of the proposed pixel circuit ranges from 0.5 to 3.12 V, which is up to 4.37× wider than the previously published pixel circuits. The emission current error of the proposed pixel circuit varies from ?2.1% to 2.08%, under the condition of ±5 mV threshold voltage variation for the driving transistor. The maximum emission current error changes from ?10.36% to ?2.62% when the OLED turn-on voltage is increased by 5 to 20 mV due to device aging. Furthermore, the proposed pixel circuit only occupies a layout area of 8.1 μm × 4 μm.
关键词： Aging,high uniformity,compensation,organic light-emitting diode on silicon (OLEDoS),threshold voltage variation
更新于2025-09-16 10:30:52
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Impact of optimum power factor of PV-controlled inverter on the aging and cost-effectiveness of oil-filled transformer considering long-term characteristics
摘要： The photovoltaic (PV) system is one of the most widespread of the renewable energy generation systems that are being used to meet the continuously increasing energy demand. A proposed analytical method is used to find the optimum power factor of PV inverter (PVI) that leads to minimum aging, reduced energy losses cost of the transformer, lower payback period of PV system, and lower green houses gases (GHG) emissions due to the transformer energy losses. In this study, the thermal performance of a 630?kVA mineral oil-filled transformer is simulated in MATLAB programming language. For an association, it is mandatory to connect a PV system to the grid to minimise the transformer loading. The PV output power is used to study the long-term impact of the solar irradiance on the transformer thermal performance. Also, the long-term climatic characteristics are considered. The ambient temperature surrounding the transformer is considered all day long. The load current profile was measured all day long. The results show the aging and cost-effectiveness of the transformer and the payback period of PV system and GHG emissions are a function of PVI power factor.
关键词： transformer aging,PV inverter,photovoltaic system,power factor,cost-effectiveness,GHG emissions
更新于2025-09-16 10:30:52
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Assessing Neural Compensation with Visuospatial Working Memory Load using Near-Infrared Imaging
摘要： Alzheimer’s disease is characterized by the progressive deterioration of cognitive abilities particularly working memory while mild cognitive impairment (MCI) represents its prodrome. It is generally believed that neural compensation is intact in MCI but absent in Alzheimer’s disease. This study investigated the effects of increasing task load as a means to induce neural compensation through a novel visual working memory (VSWM) task using functional near-infrared spectroscopy (fNIRS). The bilateral prefrontal cortex (PFC) was explored due to its relevance in VSWM and neural compensation. A total of 31 healthy controls (HC), 12 patients with MCI and 18 patients with mild Alzheimers disease (mAD) were recruited. Although all groups showed sensitivity in terms of behavioral performance (i.e. score) towards increasing task load (level 1 to 3), only in MCI load effect on cortical response (as measured by fNIRS) was significant. At lower task load, bilateral PFC activation did not differ between MCI and HC. Neural compensation in the form of hyperactivation was only noticeable in MCI with a moderate task load. Lack of hyperactivation in mAD, coupled with significantly poorer task performance across task loads, suggested the inability to compensate due to a greater degree of neurodegeneration. Our findings provided an insight into the interaction of cognitive load theory and neural compensatory mechanisms. The experiment results demonstrated the feasibility of inducing neural compensation with the proposed VSWM task at the right amount of cognitive load. This may provide a promising avenue to develop an effective cognitive training and rehabilitation for dementia population.
关键词： mild cognitive impairment,visuospatial working memory,normal aging,functional near-infrared spectroscopy,neural compensation,mild Alzheimer’s disease
更新于2025-09-12 10:27:22
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[IEEE 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Udine, Italy (2019.9.4-2019.9.6)] 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Impact of BEOL Design on Self-heating and Reliability in Highly-scaled FinFETs
摘要： This paper investigates the impact of BEOL design on device and backend reliability – HCI, BTI, EM – due to dependence of self-heating on BEOL in highly-scaled FinFETs. Our analysis indicates that due to poor thermal coupling to substrate – in the thin fin body devices – a large part of heat flows out of BEOL. This makes self-heating, and thus device (FEOL) temperature, very sensitive to BEOL design. The heat flow through BEOL also significantly increases the metal and via temperatures. The increased temperature negatively affects the overall reliability, and one of the ways to mitigate device degradation is optimization of BEOL design.
关键词： Self-heating effect,HCI,FinFET,Reliability,BTI,EM,Impact of BEOL design,Aging
更新于2025-09-12 10:27:22
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Terahertz Dielectric Spectroscopic Analysis of Polypropylene Aging Caused by Exposure to Ultraviolet Radiation
摘要： Terahertz dielectric spectroscopy is shown to be an effective tool for bench-marking ultraviolet aging of polypropylene. In this, thin-film polypropylene samples exposed to standard artificial ultraviolet radiation in accelerated aging from 1 day to 30 days are closely monitored by a terahertz time-domain spectroscopy system and analyzed using an effective data processing method. It is found that the terahertz absorption of the polypropylene samples is generally weak and the terahertz dielectric constant varies slightly though discernibly during the aging process, with the refractive index decreasing slightly with increasing length of ultraviolet exposure. Nonetheless, the rate of variation of the polypropylene refractive index with increasing terahertz frequency exhibits a drastic inflection around the 15-days aging point and the rate changes suddenly from positive value to negative value. Based on this prominent and consistent THz dielectric spectroscopic feature of the aging process, an efficient judging criterion is established to distinguish the early-term, mid-term, and late-term phases as well as the degree of polypropylene ultraviolet aging, corresponding to the fundamental transformation of the polymer material from a nonpolar to a polar substance at a critical level of oxidation induced by ultraviolet radiation.
关键词： ultraviolet aging,polypropylene,THz dielectric spectroscopy
更新于2025-09-12 10:27:22