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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) - Determination of Crystallinity, Composition, and Thermal stability of Ethylene Vinyl Acetate Encapsulant used for PV Module Lamination
摘要： Ethylene Vinyl Acetate (EVA) Copolymer is a most commonly used encapsulant for PV module lamination. Using cured and uncured EVA, several key characteristics of EVA have been determined. The glass transition temperature, peak melting point, degree of crystallinity has been determined with the help of Differential scanning calorimeter (DSC) analysis. Thermogravimetric analysis (TGA) is done to determine the Vinyl Acetate content and the thermal stability based on degradation onset temperature. This work will help to understand the thermal behavior and initial VA content estimation of the unknown grade of EVA encapsulant, which greatly affects the final module reliability.
关键词： encapsulant,crystallinity,thermal stability,ethylene vinyl acetate,photovoltaics
更新于2025-09-19 17:13:59
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Yellow/Orange-Emitting ABZn2Ga2O7:Bi3+ (A = Ca, Sr; B = Ba, Sr) Phosphors: Optical Temperature Sensing and WLED Applications
摘要： Recently, there is growing interest in developing Bi3+-activated luminescence materials for optoelectronic applications. Herein, new yellow/orange-emitting ABZn2Ga2O7:Bi3+ (ABZGO, A = Ca, Sr; B = Ba, Sr) phosphors with tunable optical properties are synthesized by alkaline earth cation substitution. When Sr2+ substitutes Ca2+ and Ba2+, the excitation wavelength has a red shift from 325 to 363 nm, matching well with the n-UV chips based WLEDs. CaBaZn2Ga2O7:0.01Bi3+ (CBZGO:0.01Bi3+) exhibits two evident emission peaks at 570 and 393 nm originating from the respective occupation of Ca and Ba sites by Bi3+ ions. The optical tuning of CBZGO:Bi3+ phosphor is achieved by changing Bi3+ doping content and excitation wavelength based on the selected site occupation. Differently, both SrBaZn2Ga2O7:0.01Bi3+ (SBZGO:0.01Bi3+) and Sr2Zn2Ga2O7:0.01Bi3+ (SZGO:0.01Bi3+) phosphors exhibit a single broad emission band, peaking at 600 and 577 nm, respectively. Two different Bi3+ sites are also verified respectively in SBZGO and SZGO hosts by the Gaussian fitting of the asymmetric PL spectra and lifetime analysis. The different luminescence behaviors of ABZGO:0.01Bi3+ phosphors should be ascribed to the synergistic effect of centroid shift, crystal-field splitting and Stokes shift. Moreover, the temperature-dependent PL spectra reveal that cation substitutions of Sr2+ for Ca2+ and Ba2+ can efficiently improve the thermal stability of ABZGO:0.01Bi3+ phosphors. In view of different thermal responses to various temperature for two emission peaks of CBZGO:0.01Bi3+ phosphor, an optical thermometer is designed and has a good relative sensitivity (Sr = 1.453% K-1) at 298 K. Finally, a WLED with CRI = 97.9 and CCT = 3932 K is obtained by combining SZGO:0.01Bi3+ and BAM:Eu2+ phosphors with a 370 nm n-UV chip, demonstrating that SZGO:0.01Bi3+ is an excellent yellow-orange-emitting phosphor for n-UV WLED devices. This work stimulates the exploration of optical tuning by cation substitution to obtain remarkable luminescence materials for optical temperature sensing and WLED applications.
关键词： optical temperature sensing,WLED applications,optical tuning,Bi3+-activated,thermal stability,luminescence materials
更新于2025-09-19 17:13:59
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Interfacial Energy Level Tuning for Efficient and Thermostable CsPbI <sub/>2</sub> Br Perovskite Solar Cells
摘要： Inorganic mixed-halide CsPbX3-based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic–inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol–gel-derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3-doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open-circuit voltage of 1.28 V, together with an increase in fill factor and short-circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3-doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C.
关键词： energy level alignment,flexible perovskite solar cells,thermal stability,all-inorganic perovskite solar cells
更新于2025-09-19 17:13:59
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Tunable lanthanide/transition metal ion‐doped novel phosphors for possible application in w‐LEDs: a review
摘要： Lanthanide-based phosphors have been extensively investigated for their possible applications in solid-state lighting technologies especially for white-light-emitting diodes. In this review article emphasis has been laid on discussing the recent developments of phosphors for warm white-light production based on various optical characteristics such as quantum efficiency, thermal stability, short emission decay time, long-term stability, facile synthesis, and low cost of production. We have tried to cover the essential and latest discoveries of the lanthanide/rare earth-doped phosphors after 2010. New generations of narrow-band phosphors have also been included. The optical and material properties of several novel phosphors and their luminescence characteristics have been thoroughly discussed.
关键词： lamp phosphor,w-LED,thermal stability,phosphor
更新于2025-09-19 17:13:59
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Hybrid Fullerene-Based Electron Transport Layers Improving the Thermal Stability of Perovskite Solar Cells
摘要： The structure-dependent thermal stability of fullerene electron transport layers (ETLs) and its impact on device stability have been underrated for years. Based on co-crystallographic understanding, herein, we develop a thermal stable ETL comprising of a hybrid layer of [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) and [6, 6]-phenyl-C61-propylbenzene (PCPB). By tuning the weight ratios of PCBM and PCPB to influence the non-covalent intermolecular interactions and packing of fullerene derivatives, we obtained a champion device based on the 20PCPB (20 wt% addition of PCPB into the mixture of PCBM: PCPB) ETL and excellent thermal stability of 500 h under 85 °C thermal aging in N2 atmosphere in the dark. The present work exemplifies that co-crystallography can be a precise tool to probe interaction and aggregation of fullerene derivatives in ETLs, and mixed fullerene derivatives can be sought as promising ETLs to enhance the long-term stability of PSCs under high-temperature working environment.
关键词： fullerenes,electron transport layer,co-crystals,Perovskite solar cells,thermal stability
更新于2025-09-19 17:13:59
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Green Solvent-Processed Organic Solar Cells Based on Low Cost Polymer Donor and Small Molecule Acceptor
摘要： Low cost photovoltaic materials and green solvent processing are important issues for commercial application of organic solar cells (OSCs). Here, we fabricated high-performance OSCs based on low-cost conjugated polymer PTQ10 as donor and small molecule n-type organic semiconductor HO-IDIC-2F as acceptor, using non-halogen tetrahydrofuran (THF) as processing solvent. The power conversion efficiency (PCE) of the as-cast OSCs reached 12.20%, which is comparable with the ones processed with chloroform (CF) (12.43%). Thermal stability of the active layer was also studied by thermal treatment at 100°C for 8 hours. As a result, the active layer morphology remained unchanged and the PCE of the devices still reached 12.13%, indicating a good thermal-stability of the PTQ10:HO-IDIC-2F blend film. As commonly known, for OSCs fabricated in larger scales, layer by layer (LL) method generally provide more advantages than the traditional D-A blend solution-processing method. Therefore, to test the compatibility of THF solvent in LL method, we fabricated the blade-coated LL devices with THF as a single type of solvent for both donor and acceptor, and the PCE could reach up to 11.85%. The surprisingly high performance of the blade-coated OSC based on green solvent indicates that PTQ10 is a promising donor to be processed in green solvent for LL technology in the future.
关键词： PTQ10,green solvent,thermal stability,organic solar cells,layer-by-layer method,HO-IDIC-2F
更新于2025-09-19 17:13:59
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Optical absorption and dispersion properties of 2-aminoanthracene-9,10- dione thin films for photodetector applications
摘要： Recent evidence suggests that the need for employing a new characteristic with low-cost preparation tools and high performance for applications. These properties have been achieved by using a high stable 2-aminoanthracene-9,10- dione thin films (AAD), prepared by thermal evaporation technique under a vacuum of 10?5 Torr. The surface of the films was checked by SEM for studying the RMS-roughness characteristics and grain – boundary influence. Added to this study, the crystalline performance was also considered as the main requirement for identifying the main crystal parameters. Most important results were focused on TGA results for confirming the thermal stability through the chosen measurements. The investigation of the spectral dependence of the absorption of the AAD films specifies the occurrence of high probability for indirect transition as compared to the direct allowed with energy gaps of 1.55 and 2.28 eV. The dispersion energy and oscillator energy, as well as most parameters, were computed using the well-known Wimple–DiDomenico formula under consideration of the single oscillator model. The spectral dependence of the linear and nonlinear controlling parameters were studied for subscription the prospect applications in photodetectors.
关键词： Thermal evaporation,Phototransient properties,Optical absorption,Thermal stability
更新于2025-09-16 10:30:52
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Device Structure and Passivation Options for the Integration of Scaled IGZO TFTs
摘要： The focus of this work is on the performance dependence of scaled the device structure and IGZO TFTs with variations semiconductor passivation scheme. TCAD simulation was used to provide insight on the details which establish the limits on electrostatic control. Dielectrics used for the gate and back-channel regions have been adjusted to overcome short-channel effects, along with required modifications in process recipes for PECVD passivation layers, oxygen ambient annealing, and ALD capping material. Scaled devices with channel lengths as small as L = 1 μm have been investigated and evaluated by the electrostatic behavior, and stability when subjected to thermal and bias stress. An optimized process and associated procedural details for scaled devices is presented, along with suggested options for further channel length reduction to submicron dimensions.
关键词： IGZO TFTs,scaling,TCAD simulation,electrostatic control,PECVD,short-channel effects,ALD,thermal stability,bias stress,passivation
更新于2025-09-16 10:30:52
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Lithium ion doping triggered splendid quantum efficiency and thermal stability in Li <sub/>2</sub> SrSiO <sub/>4</sub> : <i>x</i> Eu <sup>2+</sup> phosphors for optical thermometry and high luminous efficiency white-LED
摘要： Eu2+/Li+-Codoped Li2SrSiO4 orange-yellow phosphors were developed for the applications of white light-emitting diodes (white-LEDs) and optical thermometry. Under near-ultraviolet and blue light excitation, the resultant phosphors exhibited the emissions of Eu2+ ions with an optimal doping concentration of 5 mol% and the concentration quenching mechanism was prevailed to be the dipole–quadrupole interaction. Through the incorporation of Li+ ions into the host lattices, the thermal stability and internal quantum efficiency of the synthesized phosphors were boosted. When the excitation wavelengths were 419 and 449 nm, the internal quantum efficiencies of the Eu2+/Li+-codoped Li2SrSiO4 phosphors were increased to 73% and 69%, respectively. The temperature dependent emission spectra were employed to characterize the thermal stability of the studied samples. The white-LED lamps utilizing the Eu2+/Li+-codoped Li2SrSiO4 phosphors as the orange-yellow component exhibited enhanced photoelectric properties. Furthermore, based on the temperature dependent bandwidth of Eu2+ ions, the thermometric performance of the resultant compounds was studied in detail and the maximum sensitivity was 0.049 K?1. The phosphors with multi-excitation wavelengths were suitable for high luminous efficiency white-LEDs and optical thermometers.
关键词： Li2SrSiO4,Eu2+/Li+-codoped,thermal stability,quantum efficiency,phosphors,white-LEDs,optical thermometry
更新于2025-09-16 10:30:52
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Sr3(Y,Eu)(BO3)3: A thermal-stable red-emitting solid-solution phosphor for NUV LED
摘要： The search of efficient and thermal-stable red phosphors for NUV chip-based white light-emitting diodes (WLEDs) remains quite a challenge for phosphor development. Herein, a novel Eu3+-doped Sr3Y(BO3)3 red-emitting phosphor was prepared and the corresponding structural and luminescent properties were systematically studied. XRD results indicate that a complete solid solution of Sr3(Y,Eu)(BO3)3 can be formed. Sr3Y(BO3)3: Eu3+ phosphors show strong and high-purity red emission under UV excitation. Concentration quenching is almost absent in Sr3Y(1-x)Eux(BO3)3 system due to large Stokes shift of Eu3+ emission and effective Eu3+ separation by SrO8 and BO3 polyhedrons. The optimized Sr3Y(BO3)3: 0.9Eu3+ phosphor is found to have good emission stability at high temperature (70% of RT emission intensity at 473 K). The results indicate Sr3Y(BO3)3: Eu3+ is a promising NUV-excited red phosphor for LED application.
关键词： LED phosphor,Luminescence,Sr3(Y,Eu)(BO3)3,Thermal stability
更新于2025-09-16 10:30:52