- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Effect of Alkyl, Aryl, and meso-Aza Substitution on the Thermal Stability of BODIPY
摘要： The effect of peripheral alkyl, aryl, and meso-aza substitution on the thermal stability of BODIPYs in an argon or oxygen atmosphere has been analyzed using thermogravimetric study results. It has been shown that an increase in the length of 2,6-alkyl substituents to seven carbon atoms is accompanied by the growth of BODIPY thermal stability by 80°C. The greatest increase in the destruction temperature of BODIPY (by 100°C) is attained via the introduction of phenyl groups in the 1,3,5,7-positions of its dipyrromethenmethene framework. meso-Aza substitution does not almost produce any effect on the thermal stability of BODIPY dyes. The BODIPY destruction beginning temperature decreases by 60–90°C in the presence of air oxygen. The thermal stability of BODIPY tends to decrease with reducing degree and symmetry of alkyl substitution in the dipyrromethene framework. A lower thermal stability of BODIPY in comparison with zinc(II) dipyrromethenates is due to the participation of fluorine atoms in intramolecular redox processes.
关键词： phenyl substituents,thermal stability,structural,BODIPY,alkyl,aza-dipyrromethene,dipyrromethenmethene
更新于2025-09-23 15:21:01
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Channel-Length Dependent Performance Degradation of Thermally Stressed IGZO TFTs
摘要： The focus of this work is on the performance degradation of thermally stressed IGZO TFTs with SiO2 for both the gate dielectric and back-channel passivation material. I-V characteristics of TFTs with bottom-gate (BG) and double-gate (DG) electrode configurations were observed to left-shift and degrade with thermal stress. Experimental results indicate the instability occurs either directly or indirectly due to the influence of H2O within the passivation oxide above the IGZO channel region. An atomic layer deposition (ALD) alumina capping layer applied immediately following the passivation oxide anneal was successful in improving thermal stability. Channel length dependence was observed where longer channel DG devices were more prone to degradation. A hypothesis has been developed with H2O as the expected origin of this phenomenon. Experiments have been specifically designed to establish the feasibility of the proposed mechanism. Furthermore, DG devices which exhibit enhanced thermal stability are presented.
关键词： thermal stability,SiO2 passivation,ALD alumina capping,IGZO TFTs,channel length dependence
更新于2025-09-23 15:21:01
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Laser frequency combination tuning and locking technology in resonant optical gyro
摘要： Generally, resonant optical gyroscopes (ROG) based on the Sagnac effect are very sensitive to the changes of temperature and optical power, which directly affects the output of the gyroscope. To improve the frequency lock-in accuracy and thermal stability of ROG system, the technology of laser frequency combination tuning and locking is proposed and experimentally demonstrated. Using the characteristics of voltage and temperature tuning wavelength of semiconductor laser, the output frequency range of laser is increased, the temperature control system of the resonant cavity can be removed and the gyro can never be unlocked in theory. In addition, the frequency lock-in accuracy under light power fluctuation is improved. Using this technique, a long-term (1-h) bias stability of 24.7?°/h is observed. Moreover, the weight and volume of the ROG are greatly reduced.
关键词： Resonant optical gyroscope,Frequency lock-in accuracy,Laser frequency combination tuning,Thermal stability,Light power fluctuation
更新于2025-09-23 15:21:01
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Synthesis and photoluminescence properties of high thermal stability Mn4+ in orthorhombic SrLa2Mg2W2O12 red phosphor for warm w-LEDs
摘要： We successfully synthesized SrLa2Mg2W2O12:xMn4+ (x = 0.002, 0.004, 0.006, 0.008, 0.010, 0.012, 0.014) phosphors through a high-temperature solid-state reaction. The phase of sample was shown by X-ray powder diffraction (XRD). The morphology of the sample was observed by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM), which showed the irregular morphology of SrLa2Mg2W2O12 (SLMW) powders. Additionally, the photoluminescence excitation (PLE), emission (PL) and ultraviolet–visible reflection spectra were also presented. As shown in results, the phosphor could be stimulated by the ultraviolet (UV) and near ultraviolet (NUV) light and then exhibited far-red emission (697?nm). The optimum doping concentration of Mn4+ is 1?mol%. The thermal stability of phosphors has been investigated and discussed (I423K/I298K = 64.6%), and the internal quantum efficiency (IQE) of SLMW:0.01Mn4+ phosphors is as high as 51.2%. Finally, a far-red light-emitting diodes (LEDs) was fabricated by combining a 365?nm near-ultraviolet InGaN chip with SLMW:0.01Mn4+ phosphor. The Color Rendering Index (CRI), correlated color temperature (CCT) and luminescent efficiency (LE) values were 29.5, 1159?K and 5.6?lm/W, respectively. All of these indicated that SLMW:Mn4+ as a far-red phosphor can be applied to LEDs lamp and it has enormous potential applications in white light-emitting diodes (w-LEDs).
关键词： SrLa2Mg2W2O12:Mn4+,far-red emission,thermal stability,w-LEDs,phosphor
更新于2025-09-23 15:21:01
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Synthesis and photoluminescence properties of Ca4La6(PO4)2(SiO4)4O2: Dy3+ phosphor with high thermal stability for white light-emitting diodes
摘要： Novel yellow emitting Ca4La6(PO4)2(SiO4)4O2: Dy3+ phosphors were synthesized by high-temperature solid-state reaction method. The crystal structure, diffuse reflection, photoluminescence, and photoluminescence excitation spectra, decay curves, as well as thermal stability were investigated in detail. Under 346?nm excitation, the phosphor exhibits two strong emission peaks at 479?nm and 585?nm, with the CIE coordinates located in the yellow region. When heated up to 150?°C, the Ca4La6(PO4)2(SiO4)4O2: 0.06Dy3+ phosphor still has 83% of the initial PL intensity at room temperature, indicating its high thermal stability. The results suggest that the as-prepared Ca4La6(PO4)2(SiO4)4O2: Dy3+ phosphor could serve as a promising candidate for near-ultraviolet white light-emitting diodes.
关键词： photoluminescence,Ca4La6(PO4)2(SiO4)4O2:Dy3+,thermal stability,white light-emitting diodes,phosphor
更新于2025-09-23 15:21:01
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Stabilization of highly efficient and stable phasea??pure FAPbI3 Perovskite Solar Cells by Molecularly Tailored 2Da??Overlayers
摘要： Due to their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinum (FA+) as A cation are presently the focus of intense research, The superior chemical and thermal stability of FA+ cations renders α-FAPbI3 more suitable for solar cell applications than methylammonium lead iodide (MAPbI3). However, its spontaneous conversion to the yellow non-perovskite phase (δ-FAPbI3) under ambient conditions poses a serious challenge for practical applications. Here, we report on the stabilization of the desired α-FAPbI3 perovskite phase by protecting it with a two-dimensional (2D) IBA2FAPb2I7 (IBA = iso-butylammonium overlayer, formed via stepwise annealing. Remarkably, the α-FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23%. In addition, it showed excellent operational stability, retaining ~85% of its initial efficiency under severe combined heat and light stress, i.e. simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over a period of 500 h.
关键词： FAPbI3,Thermal Stability,Perovskite Solar Cells,Additive Engineering
更新于2025-09-23 15:21:01
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Enhanced thermal stability of inverted perovskite solar cells by interface modification and additive strategy
摘要： Inverted perovskite solar cells (PSCs) have recently gained increasing attention because of the long operation lifetime achieved. However, bathocuproine (BCP): a commonly used buffer layer in inverted PSCs, is experimentally confirmed by us to show fast aggregation at the temperature of 85 °C, which is the protocol temperature required by the International Electrotechnical Commission (IEC) standard. This thermal instability of the BCP interfacial layer makes long-term thermal stability of inverted PSCs questionable. Simply removing or replacing it can directly lead to an inferior PCE of a device. We solve this problem by removing the BCP layer and simultaneously increasing the thickness of C60, which obtains a high efficiency of 18% comparable with the device with BCP. This is possibly attributed to the extended migration path of carriers from C60 to metal electrode Ag, consequently reducing the carrier accumulation at the interface. In addition to the interfacial modification, the addition of ionic liquid: BMIMBF4 into perovskite can further improve a device's thermal stability by its effective suppression of perovskite decomposition. The devices with 0.4 mol% of BMIMBF4 exhibit promising thermal stability by retaining 80% of their initial PCE after thermal aging of 400 h at 85 °C.
关键词： BMIMBF4,BCP,thermal stability,perovskite solar cells,C60
更新于2025-09-23 15:21:01
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Thermal degradation behavior of self-assembled monolayer surfactant on silicon substrate
摘要： In nanoimprint lithography, a release agent on the mold surface is usually necessary for easy demolding between the mold and the imprinted (thermal) resist. In this work, the thermal stability of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) monolayers is studied using x-ray photoelectron spectroscopy. The FDTS monolayers are deposited on Si (100) substrates via vapor phase reactions. Significant fluorine desorption of the monolayers is observed for samples annealed at 250 and 300 °C in air. The fluorine coverage decreases as a function of annealing time at a given annealing temperature. The desorption is proposed to be dependent on the monolayer packing details and may be influenced by the intermolecular heat transfer. Removal of the CF3 groups is found to be faster than that of the CF2 group as evidenced by the CF2/CF3 peak area ratios that increase with the annealing time. Sessile drop water contact angle and fluorine coverage evolution results show that the estimated useful coating lifetime is 180 min when the samples are annealed at 300 °C and ～560 min when annealed at 250 °C. The peak position of the binding energy of the F 1s spectral line is related to the monolayer fluorine coverage and it may be a result of the interactions between the molecular chain and the negatively charged silicon substrate. Furthermore, nearly no chain desorption is detected for samples annealed in an inert environment, which may be attributed to the elimination of reactive oxygen and moisture molecules. The thermal degradation behaviors in ambient and inert atmosphere provide useful information for designing a nanoimprint process for the commercial manufacturing of polymeric microstructure and nanostructure.
关键词： fluorine desorption,x-ray photoelectron spectroscopy,thermal stability,FDTS monolayers,nanoimprint lithography
更新于2025-09-23 15:21:01
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A novel double-perovskite LiLaMgTeO6: Mn4+ far-red phosphor for indoor plant cultivation white LEDs: Crystal and electronic structure, and photoluminescence properties
摘要： Deep-red-emitting Mn4t activated oxide phosphors are the hot research topic due to their potential applications in indoor plant cultivation LEDs. In this paper, a novel double-perovskite LiLaMgTeO6:Mn4t phosphor was firstly prepared by high-temperature solid-state reaction method and its structure of the phosphor was determined by X-ray diffraction (XRD) and Rietveld refinement. Density functional theory (DFT) calculations using VASP provide an insight into the bandgap and electronic structures of the LiLaMgTeO6 host. Under UV or blue excitation, LiLaMgTeO6:Mn4t shows a good stability and bright far-red light in the 540e800 nm range with the maximum at 708 nm, which matches well with the absorption band of phytochrome PFR, indicating its potential application in improving plant growth. The optimal Mn4t doping concentration was approximately 0.6 mol%. Furthermore, a white-LEDs device made of a 365 nm chip coated with present phosphor and commercial green, blue phosphors was designed for indoor plant cultivation. The results indicate that the LiLaMgTeO6: Mn4t phosphor possesses great application prospect in white-LEDs for plant cultivation.
关键词： Far red emission,Phytochrome,Double perovskite,LEDs,Thermal stability,Indoor plant cultivation
更新于2025-09-23 15:21:01
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Stabilization of highly efficient and stable phasea??pure FAPbI3 Perovskite Solar Cells by Molecularly Tailored 2Da??Overlayers
摘要： Due to their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinum (FA+) as A cation are presently the focus of intense research, The superior chemical and thermal stability of FA+ cations renders α-FAPbI3 more suitable for solar cell applications than methylammonium lead iodide (MAPbI3). However, its spontaneous conversion to the yellow non-perovskite phase (δ-FAPbI3) under ambient conditions poses a serious challenge for practical applications. Here, we report on the stabilization of the desired α-FAPbI3 perovskite phase by protecting it with a two-dimensional (2D) IBA2FAPb2I7 (IBA = iso-butylammonium overlayer, formed via stepwise annealing. Remarkably, the α-FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23%. In addition, it showed excellent operational stability, retaining ~85% of its initial efficiency under severe combined heat and light stress, i.e. simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over a period of 500 h.
关键词： FAPbI3,Thermal Stability,Perovskite Solar Cells,Additive Engineering
更新于2025-09-23 15:21:01