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Widening the 2D/3D Perovskite Family for Efficient and Thermal-Resistant Solar Cells by the Use of Secondary Ammonium Cations
摘要： While 2D/3D layered perovskites have been the object of comprehensive research principally focused on increasing the long-term stability observed in 3D perovskites, significant opportunities still exist concerning the application of different kinds of cations outside the sphere of primary amines, which are the cations most usually applied. Our results demonstrate that the materials and the solar cells prepared with dipropylammonium iodide (DipI), a bulky secondary ammonium cation of small size, lead to obtaining materials that are not only efficient and thermodynamically stable but also robust toward heat stress. Time-resolved studies indicate longer carrier lifetime for 2D/3D layered perovskites fabricated with this bulky cation than for systems based on bulky primary ammonium cations, which allowed us to obtain PCE = 12.51% (n = 10), 15.78% (n = 50), and 17.90% (n = 90). We determine that the concentration of perovskite material after 240 min at 100 °C is up to 575% greater in the 2D/3D perovskite (n = 10) than that observed in 3D perovskite films. The material stability also improves the thermal stability of the photovoltaic devices, presenting an efficiency drop of just 4% for n = 50 and n = 10 after thermal annealing while the performance drop for reference 3D samples in the same conditions was greater than 80%.
关键词： carrier lifetime,2D/3D perovskites,solar cells,thermal stability,secondary ammonium cations
更新于2025-09-19 17:13:59
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Mechanistic insights into the effect of polymer regioregularity on thermal stability of polymer solar cells
摘要： Thermal stability is a bottleneck toward commercialization of polymer solar cells (PSCs). The effect of PCBM aggregation in multi-length-scale on the bulk-heterojunction (BHJ) structure, performance, and thermal stability of PSCs is studied here by grazing-incidence small- and wide-angle X-ray scattering. The evolution of hierarchical BHJ structures of the blend film tuned by regioregularity of polymers from the as-cast state to the thermally unstable state was systematically investigated. The thermal stability of PSCs with high polymer regioregularity value can be improved because of the good mutual interaction between polymer crystallites and fullerene aggregation. The insights obtained from this study provide an approach to manipulate the film structure in a multi-length scale and to enhance the thermal stability of P3HT-based PSCs.
关键词： PCBM aggregation,bulk heterojunction,nanostructure,polymer solar cell,GIXRD,thermal stability
更新于2025-09-19 17:13:59
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A Study on the Effect of Ultrashort Pulsed Laser Texturing on the Microstructure and Properties of Metastable S Phase Layer formed on AISI 316L Surfaces
摘要： Austenitic stainless steels (ASS) are an important material within the food and medical industries. However, their current limitations of poor wear resistance and susceptibility to bacterial colonisation have limited further uptake. Low-temperature plasma nitriding can address the poor durability of the ASS alloys by forming the S phase, therefore, providing combined improvement in hardness, wear resistance and corrosion resistance. Additionally, pulsed laser texturing can also be used to introduce functional antibacterial textures. However, due to the thermal nature of laser patterning and the thermodynamic metastability of the S phase, almost no research has been conducted thus far on combining the technologies. Therefore, this study for the first time has investigated the response of S phase treated surfaces to ultrashort (nano and femtosecond) laser texturing. The results have shown that, both theoretically and in practice, laser pulses within the nanosecond regime led to the damage of the surface, decomposition of the metastable S phase and loss of the corrosion resistance. In contrast, no change of the S phase surface layer could be detected following femtosecond laser texturing. Hence, demonstrating the feasibility of texturing S phase surfaces using femtosecond pulsed lasers, thus paving the way towards long-lasting multi-functional antibacterial stainless steel surfaces.
关键词： low-temperature nitriding,active-screen plasma,S phase,AISI 316L,thermal stability,pulsed laser texturing
更新于2025-09-19 17:13:59
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Enhanced thermal stability of InP quantum dots coated with Al-doped ZnS shell
摘要： Colloidal InP quantum dots (QDs) have attracted a surge of interest as environmentally friendly light-emitters in downconversion liquid crystal displays and light-emitting diodes (LEDs). A ZnS shell on InP-based core QDs has helped achieve high photoluminescence (PL) quantum yield (QY) and stability. Yet, due to the difficulty in the growth of a thick ZnS shell without crystalline defects, InP-based core/shell QDs show inferior stability against QY drop compared to Cd chalcogenide precedents, e.g., CdSe/CdS core/thick-shell QDs. In this work, we demonstrate the synthesis of InP-based core/shell QDs coated with an Al-doped ZnS outer shell. QDs with an Al-doped shell exhibit remarkable improvement in thermal and air stability even when the shell thickness is below 2 nm, while the absorption and PL spectra, size, and crystal structure are nearly the same as the case of QDs with a pristine ZnS shell. X-ray photoelectron spectroscopy reveals that Al3+ in Al-doped QDs forms an Al-oxide layer at elevated temperature under ambient atmosphere. The as-formed Al-oxide layer blocks the access of external oxidative species penetrating into QDs and prevents QDs from oxidative degradation. We also trace the chemical pathway of the incorporation of Al3+ into ZnS lattice during the shell growth. Furthermore, we fabricate QD-LEDs using Al-doped and undoped QDs and compare the optoelectronic characteristics and stability.
关键词： quantum yield,QD-LEDs,photoluminescence,Al-doped ZnS shell,X-ray photoelectron spectroscopy,InP quantum dots,thermal stability
更新于2025-09-19 17:13:59
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Energy transfer and thermal stability of novel green-emitting Ca3Y(PO4)3:Ce3+, Tb3+ phosphors for white LEDs
摘要： A novel thermally high-stable and high-e?ciency green-emitting Ce3+/Tb3+ co-doped Ca3Y(PO4)3 phosphor has been successfully synthesized via a conventional solid-state reaction. The energy transfer and thermal quenching of Ca3Y(PO4)3:Ce3+, Tb3+ samples were investigated for the ?rst time. The emission spectra of as-prepared samples presented a blue emission band deriving from the 5d-4f transition of Ce3+ and green emission peaks stemmed from 5D4-7FJ (J = 6, 5, 4, 3) of Tb3+ upon 325 nm excitation. By adjusting Tb3+ concentration, the chromaticity coordinates of as-prepared samples could be tuned from (0.165, 0.028) to (0.301, 0.529) because of the energy transfer of Ce3+→Tb3+ ions. It was demonstrated that the energy transfer mechanism from Ce3+ to Tb3+ ions in Ca3Y(PO4)3 host is the electric dipole-dipole interaction by the energy level diagram and the spectral overlap between the emission spectrum of the donor and the excitation spectrum of the acceptor. The energy transfer e?ciency from Ce3+ to Tb3+ ions in Ca3Y(PO4)3 was up to 81%. Beyond that, it a?rmed that the emission intensity at 423 K was about 82% of that measured at room temperature (298 K) according to the temperature-dependent emission spectra. Basing on the above analyses shows that the as-synthesized green-emitting Ce3+/Tb3+ co-doped Ca3Y(PO4)3 phosphors with high energy transfer e?ciency and excellent thermal stability could be used in phosphor-converted white light-emitting-diodes (LEDs).
关键词： Thermal stability,Luminescence,Phosphor,Ca3Y(PO4)3,Energy transfer
更新于2025-09-19 17:13:59
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High performance and stable nonfullerene acceptor-based organic solar cells for indoor to outdoor light
摘要： We synthesized a donor polymer of bis(2-ethylhexyl)thiophene-substituted benzodithiophene (BDT-Th) and 1,3-bis(2-ethylhexyl)-5,7-di(thiophene-2-yl)benzo[1,2-c:4,5-c′]dithiophene-4,8-dione, for which the BDT-Th unit includes chlorine and sulfur-bridged 2-ethylhexyl in the thiophene side group. When compared with PBDB-TF, which includes fluorine and 2-ethylhexyl in BDT-Th, PBDB-TSCl shows more efficient exciton dissociation and charge-generation, which is probably because large dipole moment changes from ground to excited states lead to reduced exciton binding energy. Consequently, despite small donor-acceptor interface in the bulk-heterojunction (BHJ) film, PBDB-TSCl achieves higher photovoltaic performance than PBDB-TF under various light intensities; PBDB-TSCl achieved higher efficiency of 13.13% than 12.12% of PBDB-TF under 1 sun illumination. Moreover, PBDB-TSCl showed the highest efficiency of 21.53% with fill factor (FF) of 76.29% under a 500 lux fluorescence lamp, whereas PBDB-TF has lower efficiency of 15.57% with FF of 65.25%. Furthermore, the PBDB-TSCl device shows improved thermal stability due to more stabilized morphology of its BHJ film.
关键词： indoor light,nonfullerene acceptor,outdoor light,organic solar cells,thermal stability,photovoltaic performance
更新于2025-09-19 17:13:59
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Thermally Stable Aua??BaTiO <sub/>3</sub> Nanoscale Hybrid Metamaterial for High-Temperature Plasmonic Applications
摘要： The thermal stability of the Au?BaTiO3 nanocomposite thin film as a hybrid metamaterial deposited by a one-step pulsed laser deposition (PLD) method has been investigated via both ex situ annealing followed by TEM analysis and an in situ heating study in TEM. For the ex situ annealing study, the XRD analysis shows good crystallinity for both as-deposited and annealed films after being annealed at 600 °C for different time periods (i.e. 1, 3, 6, and 30 hours). The optical measurements including transmittance/reflectance, ellipsometry, and Raman spectroscopy demonstrate excellent optical properties of the hybrid metamaterial films by exhibiting the static localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion in the visible to near-infrared regime. Both TEM results of the ex situ annealed samples and in situ heating TEM results reveal no obvious microstructure change after the extensive high-temperature annealing and suggest the high thermal stability of the Au?oxide hybrid materials for their future high-temperature plasmonic applications.
关键词： crystallinity,localized surface plasmon resonance,in situ,hyperbolic dispersion,hybrid metamaterial,thermal stability,ex situ
更新于2025-09-19 17:13:59
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Improved luminescence properties of a novel red dodec-fluoride phosphor Ba <sub/>3</sub> Sc <sub/>2</sub> F <sub/>12</sub> :Mn <sup>4+</sup> with extraordinary thermal stability for WLED application
摘要： Mn4+-activated red phosphors have recently attracted tremendous attention for their fascinating performance in white light emitting diodes (WLEDs) application to achieve warm white light, while the thermal stability of fluoride is still considered as a drawback. Herein, we report a novel red phosphor composed of Ba3Sc2F12:Mn4+ (BSF:Mn), in which, the emitting centers of Mn4+ ions are locating in the sites of Sc3+ ions. The photoluminescence of BSF:Mn varies with the concentration of K2MnF6, reaction temperature, and the concentrations of NH3·H2O in reaction system. Partly substituting Ba2+ with Ca2+ decreases the luminescent intensity of BSF:Mn. By employing the as-prepared phosphor BSF:Mn as a red component, a high-performance WLED with a correlated color temperature (CCT) at 4796 K and a color rendering index (CRI) of 85.2 was obtained. The phosphor BSF:Mn keeps undecomposed up to 800 oC, therefore, this work exhibits a strategy to explore a novel Mn4+-doped fluoride with particularly thermal stability.
关键词： luminescent properties,thermal stability,Ba3Sc2F12:Mn4+,Mn4+-activated red phosphors,WLEDs
更新于2025-09-19 17:13:59
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Highly Stabilized Gradient Alloy Quantum Dots and Silica Hybrid Nanospheres by Core Double Shells for Photoluminescence Devices
摘要： This Letter reports the synthesis approach and application of colloidal suspensions containing gradient alloy quantum dots (QDs) and silica hybrid spheres with improved thermal and photostability, invisible QD aggregation, and high material compatibility. These hybrid nanospheres are characterized by using silica spheres as cores, adsorbing QDs as one shell, and then coating a silica layer as another shell (termed SiO2?QD?SiO2). They were synthesized by using Sto?ber and adsorption methods. The experimental conditions affecting the optical properties were fully investigated. A light-guiding microstructure array (LGMA) was fabricated and tested for photoluminescence demonstration. After accelerated aging tests for 240 h under 85 °C, 40% relative humidity, and 450 nm blue light excitation, the luminance of the SiO2?QD?SiO2 LGMA remained stable, which was 1.6 times greater than that of untreated QD samples. This structure with long-term photothermal stability could pave the way for displays or lighting applications.
关键词： photostability,photoluminescence,thermal stability,quantum dots,silica hybrid nanospheres
更新于2025-09-19 17:13:59
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Doping Strategy for Efficient and Stable Triple Cation Hybrid Perovskite Solar Cells and Module Based on Poly(3‐hexylthiophene) Hole Transport Layer
摘要： As the hole transport layer (HTL) for perovskite solar cells (PSCs), poly(3-hexylthiophene) (P3HT) has been attracting great interest due to its low-cost, thermal stability, oxygen impermeability, and strong hydrophobicity. In this work, a new doping strategy is developed for P3HT as the HTL in triple-cation/double-halide ((FA1?x?yMAxCsy)Pb(I1?xBrx)3) mesoscopic PSCs. Photovoltaic performance and stability of solar cells show remarkable enhancement using a composition of three dopants Li-TFSI, TBP, and Co(III)-TFSI reaching power conversion efficiencies of 19.25% on 0.1 cm2 active area, 16.29% on 1 cm2 active area, and 13.3% on a 43 cm2 active area module without using any additional absorber layer or any interlayer at the PSK/P3HT interface. The results illustrate the positive effect of a cobalt dopant on the band structure of perovskite/P3HT interfaces leading to improved hole extraction and a decrease of trap-assisted recombination. Non-encapsulated large area devices show promising air stability through keeping more than 80% of initial efficiency after 1500 h in atmospheric conditions (relative humidity ≈ 60%, r.t.), whereas encapsulated devices show more than >500 h at 85 °C thermal stability (>80%) and 100 h stability against continuous light soaking (>90%). The boosted efficiency and the improved stability make P3HT a good candidate for low-cost large-scale PSCs.
关键词： perovskite interfaces,light soaking,photovoltaic module,polymeric hole transport materials,thermal stability
更新于2025-09-19 17:13:59