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Hydrogen-Bonded Two-Component Ionic Crystals Showing Enhanced Long-Lived Room-Temperature Phosphorescence via TADF-Assisted F?rster Resonance Energy Transfer
摘要： Molecular room-temperature phosphorescent (RTP) materials with long-lived excited states have attracted widespread attention in the fields of optical imaging, displays, and sensors. However, accessing ultralong RTP systems remains challenging and examples are still limited to date. Herein, a thermally activated delayed fluorescence (TADF)-assisted energy transfer route for the enhancement of persistent luminescence with an RTP lifetime as high as 2 s, which is higher than that of most state-of-the-art RTP materials, is proposed. The energy transfer donor and acceptor species are based on the TADF and RTP molecules, which can be self-assembled into two-component ionic salts via hydrogen-bonding interactions. Both theoretical and experimental studies illustrate the occurrence of effective F?rster resonance energy transfer (FRET) between donor and acceptor molecules with an energy transfer efficiency as high as 76%. Moreover, the potential for application of the donor–acceptor cocrystallized materials toward information security and personal identification systems is demonstrated, benefitting from their varied afterglow lifetimes and easy recognition in the darkness. Therefore, the work described in this study not only provides a TADF-assisted FRET strategy toward the construction of ultralong RTP, but also yields hydrogen-bonding-assembled two-component molecular crystals for potential encryption and anti-counterfeiting applications.
关键词： thermally activated delayed fluorescence,energy transfer,cocrystallization,hydrogen bonding self-assembly,room-temperature phosphorescence
更新于2025-09-10 09:29:36
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Facile Method to Synthesize N-Graphene Nano Sheets
摘要： In this paper, we reported about the facile method to generate N-Graphene Nano Sheets (N-GNS) on room temperature. The purposes of this research are to synthesize and characterize N-GNS. This research used the modified Hummers’s method to generate GNS and doping nitrogen to N-GNS used ammonia 10 M at T = 30oC. The N-GNS was characterized by using XRD, FTIR and SEM-EDX. The XRD data show that N atoms was well be deposited on GNS to form N-GNS, it was indicated by the broad and weak peak was appear at 2θ = 26.3o. This data is consistent with SEM-EDX, where the N atoms content on N-GNS is 2.72 %. FTIR data also defenitely confirm that there is interaction between C and N, indicating by the peak is appear at 1396 cm-1. All of data show that the N is exist on GNS, it probes N-GNS may synthesized by facile method on room temperature.
关键词： N-Graphene Nano Sheets,Graphene Nano Sheets,Room Temperature,Ammonia
更新于2025-09-10 09:29:36
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Direct wafer bonding of Ga2O3–SiC at room temperature
摘要： Integration of Ga2O3 on SiC substrate with a high thermal conductivity is one of the promising solutions to reduce the self-heating of Ga2O3 devices. Direct wafer bonding of Ga2O3–SiC at room temperature was achieved by surface activated bonding (SAB) using a Si-containing Ar ion beam. An average bonding energy of ~2.31 J/ m2 was achieved. Both the structure and the composition of the interface were investigated to understand the bonding mechanism. According to the interface analysis, a ~2.2 nm amorphous SiC layer and a ~1.8 nm amorphous β-Ga2O3 layer originating from the ion beam bombardment for surface activation were found at the interface. A slight di?usion at the interface might already happen at room temperature, which should contribute to the strong bonding. To con?rm the di?usion at a low temperature and investigate the possible interfacial variation during device operation, an annealing process was carried out at 473 K. The same analysis was applied on the annealed bonding interface. The interfacial layer shrank by ~0.5 nm after annealing. The further di?usion of Ga and Si at the interface caused by the annealing was con?rmed. Besides, the position of the Ar count peak inside the amorphous Ga2O3 layer shifted by ~0.5 nm toward SiC.
关键词： Ga2O3,Room temperature,Direct wafer bonding,SiC
更新于2025-09-10 09:29:36
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A Room-Temperature High-Conductivity Metal Printing Paradigm with Visible-Light Projection Lithography
摘要： Fabricating electronic devices require integrating metallic conductors and polymeric insulators in complex structures. Current metal-patterning methods such as evaporation and laser sintering require vacuum, multistep processes, and high temperature during sintering or postannealing to achieve desirable electrical conductivity, which damages low-temperature polymer substrates. Here reports a facile ecofriendly room-temperature metal printing paradigm using visible-light projection lithography. With a particle-free reactive silver ink, photoinduced redox reaction occurs to form metallic silver within designed illuminated regions through a digital mask on substrate with insignificant temperature change (<4 °C). The patterns exhibit remarkably high conductivity achievable at room temperature (2.4 × 107 S m?1, ≈40% of bulk silver conductivity) after simple room-temperature chemical annealing for 1–2 s. The finest silver trace produced reaches 15 μm. Neither extra thermal energy input nor physical mask is required for the entire fabrication process. Metal patterns were printed on various substrates, including polyethylene terephthalate, polydimethylsiloxane, polyimide, Scotch tape, print paper, Si wafer, glass coverslip, and polystyrene. By changing inks, this paradigm can be extended to print various metals and metal–polymer hybrid structures. This method greatly simplifies the metal-patterning process and expands printability and substrate materials, showing huge potential in fabricating microelectronics with one system.
关键词： hybrid material printing,metal patterning,high conductivity,flexible electronics,room-temperature printing
更新于2025-09-10 09:29:36
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Room-Temperature Bonding of Wafers with Smooth Au Thin Films in Ambient Air Using a Surface-Activated Bonding Method
摘要： Wafers with smooth Au thin ?lms (rms surface roughness: < 0.5 nm, thickness: < 50 nm) were successfully bonded in ambient air at room temperature after an Ar radio frequency plasma activation process. The room temperature bonded glass wafers without any heat treatment showed a su?ciently high die-shear strength of 47–70 MPa. Transmission electron microscopy observations showed that direct bonding on the atomic scale was achieved. This surface-activated bonding method is expected to be a useful technique for future heterogeneous photonic integration.
关键词： Au-Au bonding,surface-activated bonding,room-temperature bonding,heterogeneous integration
更新于2025-09-10 09:29:36
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A New Method to Prepare Few-Layers of Nanoclusters Decorated Graphene: Nb2O5/Graphene and Its Gas Sensing Properties
摘要： During the last decade, due to its excellent electrical, mechanical and thermal properties of chemically modified graphene has been extensively studied for many applications, such as polymer composites, energy-related materials, biomedical applications and sensors. The aim of this work is to evaluate the gas sensing performance of niobium oxide (Nb2O5) nanoclusters deposited onto few-layers graphene powder by magneton sputtering. Two different samples were prepared by changing electrical power of deposition. The materials were deeply morphologically, structurally and chemically characterized. Finally, they were deposited onto alumina substrates and their sensing properties were investigated vs. different gases, showing good sensing performance vs. ppm concentrations of NO2 at room temperature.
关键词： NO2 detection,room temperature,chemoresistive gas sensors,functionalized graphene
更新于2025-09-09 09:28:46
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Room-temperature synthesis of Mn2+-doped cesium lead halide perovskite nanocrystals via a transformation doping method
摘要： Currently, Mn2+-doped cesium lead halide perovskite nanocrystals have attracted research interests. Here, we report a novel room-temperature transformation doping method for the synthesis of Mn2+-doped CsPbCl3 and CsPb(Br/Cl)3 nanocrystals. Innovatively, the transformation of Cs4PbX6 (X=Cl, Br) phase which has no excitation emission to CsPbX3 phase which has strong luminescence was used in this mechanism. Simply injecting MnCl2 precursor into Cs4PbX6 solution could result in the full transformation of Cs4PbX6 phase to CsPbX3 phase and Mn2+-doped CsPbCl3 or CsPb(Br/Cl)3 were obtained. The basic idea for the transformation doping method is that MnCl2 can not only drive the transformation of the two structures but also Mn2+ can substitute Pb2+. In this reaction, the concentration of Mn precursor is a key influence factor. Moreover, instead of the ligand of OA, the acetic acid was used in our method. Through the adjustment of the ligand in precursor, not just the photoluminescence quantum yields of as-prepared Mn2+-doped CsPbCl3 nanocrystals were improved from 7.8 to 32.6% (Mn2+-doped CsPb(Br/Cl)3 nanocrystals even could reach to 42.7%), the nanocrystals also retained outstanding stability. We propose a combination of structure transformation and ion doping as a perovskite doping mechanism. Our doping method is a novel strategy for lead halide perovskite nanocrystals doping project and it could provide more possibilities in the future.
关键词： photoluminescence quantum yields,Cs4PbX6,Mn2+-doped cesium lead halide perovskite nanocrystals,CsPbX3,room-temperature transformation doping method
更新于2025-09-09 09:28:46
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Rare Earth and Transition Metal Doping of Semiconductor Materials || Gadolinium-doped gallium-nitride
摘要： The race toward a dilute magnetic semiconductor (DMS) that exhibits room-temperature (RT) ferromagnetism has been in progress for about 15 years, sparked by the theoretical prediction that the two wide band-gap semiconductors GaN and ZnO would show a Curie temperature (TC) above 300 K if doped with 5% of Mn and a large hole concentration of 1 (cid:1) 1020/cm3 (Dietl et al., 2000). Despite apparent experimental evidence that RT magnetic order was already reported by many groups shortly after the theoretical prediction, the subject remained unusually controversial in the following years. Dietl (2010) summarizes that after 10 years of research the existence of ferromagnetism is well established for GaAs:Mn and related systems but it remains the major goal in the ?eld to achieve TCs at or above 300 K. Around the same time a review of a large group of theorists summarize: “The results of ab initio calculations seem to suggest that it is rather unlikely to obtain TC values as high as room temperature or above in this range” (Sato et al., 2010). Nonetheless persistent experimental claims of TCs above 300 K for a range of DMS materials can be found up to today. Thus it is worth trying to get a broader view on a given materials systems and compare a range of samples from different sources to elucidate whether these reports are characteristic of the DMS material itself (system-speci?c) or if only peculiarities of a given specimen are reported (sample-speci?c). Only in the former case can we consider those ?ndings to be useful for future potential applications in spintronic devices that have to be operational at ambient conditions.
关键词： ferromagnetism,room-temperature,GaN,Gd doping,dilute magnetic semiconductor
更新于2025-09-09 09:28:46
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Room Temperature Bonding of Wafers Using Si and Ge Films with Extremely Low Electrical Conductivity
摘要： The technical potential of room temperature bonding of wafers in vacuum using amorphous Si (a-Si) and Ge (a-Ge) films was studied. Transmission electron microscopy images revealed no interface corresponding to the original films surfaces for bonded a–Ge–a–Ge films. Analyses of film structure and the surface free energy at the bonded interface revealed higher bonding potential at the connected a–Ge–a–Ge interface than that of a–Si films. The electrical resistivity of a-Ge films is 0.62 ?m, which is lower than that of a-Si film (4.7 ?m), but 7–8 order higher than that of representative material films used for bonding in vacuum. Our results indicate that room temperature bonding using a–Ge films is useful to bond wafers without any marked influence on the electrical properties of devices on wafer surfaces caused by the electrical conductivity of films used for bonding.
关键词： room temperature bonding,electrical conductivity,amorphous Ge,wafer bonding,amorphous Si
更新于2025-09-09 09:28:46
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Ultralong Organic Phosphorescence in the Solid State: the Case of Triphenylene Cocrystals with Halo- and Dihalo-penta/tetrafluorobenzene
摘要： The polycyclic aromatic hydrocarbon (PAH) triphenylene (TP) has been reacted with halo-pentafluorobenzene (XF5, X = Br, I) and 1,4-dihalo-tetrafluorobenzene (X2F4, X = Br, I) to yield the corresponding cocrystals TP·BrF5, TP·Br2F4, TP·IF5, and TP·I2F4 form I. These materials have been synthesized by dissolving TP into an excess of liquid or molten co-former, and single crystals have been grown via seeding chloroform solutions. They have been fully characterized by a combination of techniques including X-ray diffraction, Raman, and luminescence spectroscopy in the solid state. TP·I2F4 form I was found to undergo a single-crystal to single-crystal (SCSC) polymorphic phase transition induced by temperature (when cooled down to 100K) leading to the new form TP·I2F4 form II, which is transformed back into the first structure when brought again at RT. This behavior was confirmed also by Raman spectroscopy. Upon cocrystallization and as a result of the external heavy atom effect, all crystalline materials exhibited bright room temperature phosphorescence clearly visible by naked eye. The latter was almost exclusive for cocrystal TP·I2F4, whereas for TP·Br2F4 both fluorescence and phosphorescence were detected. In TP·Br2F4, the phosphorescence lifetime was of the order of 200 ms, and with the visual outcome of an orange phosphorescence lasting for a couple of seconds upon ceasing the excitation, that makes this compound classifiable as an Ultralong Organic Phosphorescent (UOP) material. The results evidenced the role of the nature of the heavy atom in governing the phosphorescence output from organic cocrystals.
关键词： Room Temperature Phosphorescence,Triphenylene Cocrystals,Ultralong Organic Phosphorescence,Dihalo-tetrafluorobenzene,Halo-pentafluorobenzene
更新于2025-09-09 09:28:46