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Biocompatible photoluminescent silk fibers with stability and durability
摘要： Exploring photoluminescent silk fibers, possessing biocompatibility as well as stable and durable fluorescent properties, is a requirement for the development of novel photoluminescent biomaterials. Herein, we fabricate photoluminescent silk fibers, TPCA@SF, via modifying an organic fluorescent molecule (5-oxo-3,5-dihydro-2H-thiazolo [3,2-a] pyridine-7-carboxylic acid, TPCA) onto silk fibers, along with using quaternary ammonium salt didodecyldimethylammonium bromide (DDAB) as color fixing agent. The hydrogen bonds and electrostatic association among silk fibers, TPCA and DDAB ensure the stable modification. The facile and green fabrication process is achieved in water under mild conditions without using any toxic substances. The TPCA@SF manifests the combining features of high quantum yield, fluorescence water-fastness, anti-photobleaching, good mechanical property and biocompatibility. The strategy holds great potential for exploring various biocompatible photoluminescent substances with stability and durability.
关键词： wash-durability,biocompatibility,photoluminescence,silk fibers,anti-photobleaching
更新于2025-11-21 11:24:58
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Ultra-flexible perovskite solar cells with crumpling durability: toward a wearable power source
摘要： Perovskite materials hold great potential as photovoltaic power sources for portable devices owing to their mechanical flexibility and high performance; however, the flexibility and e?ciency require further improvement to attain practical viability. We investigated the mechanical fracture behavior of polycrystalline perovskite films by varying the substrate thickness and applying the neutral plane concept. This enabled us to fabricate a crack-free perovskite film on an ultra-thin substrate (B2.5 mm) and to demonstrate ultra-flexible solar cells with high e?ciency (17.03%) with unprecedented flexibility sustained after 10 000 cycles of bending at a 0.5 mm radius. This represents a high e?ciency of 13.6% for large-area flexible perovskite solar cells (1.2 cm2), fabricated by using a hybrid transparent electrode composed of a metal mesh grid and conducting polymer. Using a protective layer to achieve the neutral plane concept, our ultra-flexible perovskite solar cells are demonstrated to be durable even after 100 crumpling cycles. Our approach paves the way to fabricate flexible perovskite solar cells for portable power sources.
关键词： wearable power source,Perovskite solar cells,mechanical durability,neutral plane concept,flexible
更新于2025-11-21 10:59:37
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Acceptance criteria for accelerated aging testing of silvered-glass mirrors for concentrated solar power technologies
摘要： Solar reflectors for Concentrating Solar Power (CSP) technologies are required to maintain their optical properties in demanding environments for more than 20 years of service-life. The durability of the commonly used silvered-glass reflectors is typically qualified by means of accelerated aging. Recently, the Spanish standardization committee UNE has published the first specific standard for this topic, which defines a set of accelerated aging tests for CSP reflectors. However, the standard does not contain pass/fail criteria. This paper proposes useful acceptance criteria for the accelerated tests defined by UNE, helping to interpret the obtained degradation results. The criteria have been determined by analyzing the collected accelerated aging data over the past 5 years in the OPAC laboratory, a joint research group of DLR and CIEMAT. Data from six different 4 mm silvered-glass manufacturers is presented, covering nearly the entire market of commercially available silvered-glass mirrors, and going way beyond the recommended testing times of the UNE standard. The data may be used to benchmark initial reflective properties (before aging) and the performance during accelerated durability testing. In addition, recommendations for improvements of the standard are given and an estimate of the acceleration factor of the Copper Accelerate Salt Spray (CASS) test with respect to a highly corrosive outdoor environment is presented.
关键词： Durability,Accelerated aging testing,Reflectance,Acceptance criteria,Solar reflector,Concentrated solar power
更新于2025-10-22 19:40:53
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Durability and purification performance of concrete impregnated with silicate and sprayed with photocatalytic TiO2
摘要： This paper proposes an integrated concrete surface treatment with surface enhancement via silicate impregnation and surface spraying with TiO2 (a photocatalyst). In this work, two types of silicate-based materials, sodium alumina silicate (SAS) and colloidal silica (COS) were used. Various tests were carried out to characterize the silicate properties and engineering performance of the impregnated concrete. In addition, the purification performance in concrete sprayed with TiO2 was investigated. Concrete impregnated with silicate and sprayed with TiO2 showed an improvement in the durability and mechanical performance because of the addition of the CSH gel and TiO2 barrier. After impregnation, the TiO2 applied by spraying retained good performance for the removal of acetaldehyde and methyl orange.
关键词： Sodium alumina silicate,Durability performance,Purification performance,Photocatalyst,Colloidal silica
更新于2025-09-23 15:22:29
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Predicting Mechanical Strength of In-Use Firefighter Protective Clothing Using Near-Infrared Spectroscopy
摘要： The exact lifespan of in-use firefighter protective clothing is difficult to predict due to the large variations in use between individual garments. Furthermore, testing methods used to evaluate new protective clothing are destructive in nature and could not be applied to in-use garments. Various non-destructive techniques have been proposed for the evaluation of in-use clothing, each possessing its own advantages and disadvantages. The ability of near-infrared spectroscopy to predict the tensile strength of thermally aged fabrics used in protective clothing for wildland firefighters and other workers is investigated here. Fabrics were exposed to heat fluxes from 10 kW/m2 to 40 kW/m2 for various durations using the cone calorimeter, after which the tensile strength of the fabrics was measured. Temperatures measured during the exposures and results of thermal gravimetric analysis tests were used to interpret changes in tensile strength. Multivariate linear regression was used to develop correlations between the tensile strength and the reflectance values measured between 1500 nm and 2500 nm for new and thermally aged fabrics. It was found that models based on reflectance measurements made at as few as three wavelengths could be used to estimate the tensile strength of the thermally aged specimens.
关键词： Thermal ageing,Near-infrared spectroscopy,Firefighter,Durability,Non-destructive testing,Protective clothing
更新于2025-09-23 15:22:29
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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) - The Impact of Cold Temperature Exposure in Mechanical Durability Testing of PV Modules
摘要： Existing mechanical durability testing sequences typically perform mechanical loading prior to environmental exposures such as thermal cycling or humidity freeze. Recent work has shown that the fracture strength of silicon solar cells can reduce after exposure to temperatures below -20°C. In an effort to better evaluate modules with respect to cell crack durability, we explore the use of a single thermal cycle prior to mechanical loading. Modules were exposed to a static front-side load before and after exposure to a single thermal cycle and were characterized with current-voltage measurements and electroluminescence imaging. The results show a significant increase in the number of cell cracks that are generated at a given load after a single cold exposure. We explore how this can be used to further optimize the qualification test sequence for mechanical durability.
关键词： cell fracture,photovoltaic modules,mechanical durability,reliability,silicon
更新于2025-09-23 15:21:01
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Natural Sugar Assisted Chemically Reinforced Highly Durable Piezo-Organic Nanogenerator with Superior Power Density for Self-Powered Wearable Electronics
摘要： Natural piezoelectric material is of increasing interest particularly for applications in biocompatible, implantable, and flexible electronic devices. In this paper we introduce a cost effective, easily available natural piezoelectric material, i.e., sugar in the field of wearable piezoelectric nanogenerator (PNG) where low electrical output, biocompatibility and performance durability are still critical issues. We report on a high performance piezo-organic nanogenerator (PONG) based on the hybridization of sugar encapsulated polyvinylidene fluoride (PVDF) nanofiber webs (SGNFW). We explore the crucial role of single crystal sugar having fascinating structure along with the synergistic enhancement of piezoelectricity during nano-confinement of sugar interfaced macromolecular PVDF chains. As a consequence, the SGNFW based PONG exhibits outstanding electricity generation capability (for example ~100V under 10 kPa human finger impact and maximum power density of 33 mW/m2) in combination with sensitivity to abundantly available different mechanical sources (such as wind flow, vibration, personal electronics and acoustic vibration). Consequently, it opens up suitability in multifunctional self-powered wearable sensor designs for realistic implementation. In addition, commercially available capacitors are charged up effectively by the PONG due to its rapid energy storage capability. The high performance or the PONG not only offers the “battery free” energy generation (several portable units of LEDs and a LCD screen are powered up without using external storage) but also promises its use in wireless signal transmitting systems that widens the potential in personal health care monitoring. Furthermore, owing to the geometrical stress confinement effect, the PONG is proven to be a highly durable power generating device validated by stability test over 10 weeks. Therefore, the organic nanogenerator would be a convenient solution for portable personal electronic devices that are expected to operate in a self-powered manner.
关键词： self-powered electronics,PVDF,organic piezoelectric nanogenerator,high performance and durability,Natural piezoelectric material,sugar
更新于2025-09-23 15:21:01
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Development of ethylene-vinyl acetate copolymer/graphene oxide nanocomposites for crystalline silicon photovoltaic modules
摘要： Renewable sources of energy, such as solar cells, stand out as promising sustainable alternatives, given the growing world energy demand. The crystalline silicon photovoltaic (PV) modules are the most used in the conversion of solar energy into electricity. These modules are subject to weather conditions that may cause degradation of the ethylene vinyl acetate copolymer (EVA) encapsulant (cross-linked EVA copolymer), affecting the efficiency, stability and service life of the PV conversion. In this work, the development of an encapsulant was performed, based on the addition of graphene oxide (GO) to EVA encapsulant forming the nanocomposite (EVA/GO), in order to improve the stabilization against photodegradation. Nanocomposites with GO concentrations wt. %: 0.25%, 0.50%, 0.75%, 1.0% and 2.0% were characterized by: Fourier transform infrared spectroscopy by attenuated total reflectance (ATR-FTIR) thermogravimetry (TG), and differential scanning calorimetry (DSC), before and after they underwent accelerated aging processes in Weather-Ometer and UVB rays chambers. In general, the addition of GO minimized EVA encapsulant degradation. Only the encapsulant with GO concentration of 0.25 wt% was shown as promising for photovoltaic modules, since the transparency of the films with higher concentrations was impaired.
关键词： Aging,Durability,Thermal analysis,Photovoltaic encapsulant,EVA/GO nanocomposite,Infrared spectroscopy
更新于2025-09-23 15:19:57
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Degradation in photovoltaic encapsulation strength of attachment: Results of the first PVQAT TG5 artificial weathering study
摘要： Delamination of the encapsulant in photovoltaic (PV) module technology results in immediate optical loss and may enable subsequent corrosion or mechanical damage. The effects of artificial weathering were not previously known; therefore, an empirical study was performed to survey the factors most affecting adhesion, including the ultraviolet (UV) source (ie, Xe or fluorescent lamp[s]), the optical filters for the lamp, the chamber temperature, and the relative humidity. Natural weathering was also performed at locations, including the following: Golden, Colorado; Miami, Florida; Phoenix, Arizona; QiongHai, China; Riyadh, Saudi Arabia; and Turpan, China. Specimens were constructed using a laminated glass/poly (ethylene-co-vinyl acetate)/glass geometry. The compressive shear test (CST) was used to quantify the mechanical strength of attachment, taken as a proxy for adhesion. The fractography of select specimens (including cross-sectional optical microscopy) was used to verify the failure mode (delamination or decohesion). Additional analysis of the local solar spectrum as well as the specimen temperature was performed to interpret the results of natural weathering. The goals of this study include to identify the most significant stressors, clarify where strong coupling may occur between stressors, and validate accelerated test results relative to natural weathering. The importance of specimen conditioning (for moisture) and hygrometric degradation as well as the effects of UV degradation are identified in this study.
关键词： EVA,durability,reliability,xenon,UVA-340
更新于2025-09-23 15:19:57
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Tuning the Color Palette of Semi-Transparent Solar Cells via Lateral ??-Extension of Polycyclic Heteroaromatics of Donora??Acceptor Dyes
摘要： Durable solar cells with tunable color and diaphaneity are very promising for building integrated photovoltaic applications. In this paper we employ donor–acceptor organic dyes U3, U4, U5, and R6 featured by polycyclic heteroaromatics 6,12-dihydroindeno[1,2-b]indeno[2',1':4,5]thieno[2,3-d]thiophene (IT2), 7,15-dihydrobenzo[6',7']indeno[2',1':4,5]thieno[3,2-b]benzo[6,7]indeno[2,1-d]thiophene (BIT2), 7,15-dihydrophenaleno[1,2-b]phenaleno[2',1':4,5]thieno[2,3-d]thiophene (PT2), and 9,19-dihydrobenzo[1',10']phenanthro[3',4':4,5]thieno[3,2-b]benzo[1,10]phenanthro[3,4-d]thiophene (BPT2) to fabricate semi-transparent dye-sensitized solar cells (DSSCs). The U3, U4, U5, and R6 based cells are goldenrod, crimson, red, and sapphire blue, with power conversion efficiencies of 3.5%, 8.2%, 7.6, and 10.1% at the AM1.5G conditions. Density functional theory calculation and voltammetric measurement reveal that lateral π-extension of polycyclic heteroaromatic brings forth a downward displacement of lowest unoccupied molecular orbital, affording a high molar extinction coefficient, low-energy gap blue dye. Femtosecond fluorescence decay measurements of dyed titania and alumina films unravel the electron injection yields of photo-excited dye molecules, which are well correlated with the maximal values of external quantum efficiencies of DSSCs. After 1,000 h full sunlight soaking at 60 oC, the red and blue DSSCs exhibit stable photocurrents, owing to the strong bonding and photochemical stability of dye molecules adsorbed on the surface of titania as well as the retention of close-to-unity electron collection yield.
关键词： electron injection,durability,tunable color,semi-transparent solar cell,lateral π-extension,photosensitizer
更新于2025-09-23 15:19:57