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Insight into phonon scattering in Si nanowires through high-field hole transport: Impacts of boundary condition and comparison with bulk phonon approximation
摘要： The impact of how to model phonon scattering on hole transport in Si nanowires was studied based on Boltzmann’s transport equation. Boundary conditions for atomistic description of phonons in nanowires and approximation by bulk acoustic and optical phonons were analyzed in terms of their impacts on high-field hole transport. The boundary conditions for phonons influence the drift velocity and momentum relaxation time, especially at low electric field, but the energy relaxation time hardly depends on the boundary conditions. The impacts by the change of boundary conditions can be approximated by the change of the strength of acoustic phonon scattering in bulk phonon picture, though the behavior of energy relaxation and distribution function of holes can not be reproduced by bulk phonon approximation.
关键词： Si nanowires,boundary condition,bulk phonon approximation,phonon scattering,high-field hole transport
更新于2025-09-10 09:29:36
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Light enhanced electrochemistry and electrochemiluminescence of luminol at glassy carbon electrodes
摘要： We report in this work the enhancement effect of light irradiation on the electrochemistry and electrochemiluminescence (ECL) of luminol at the bare glassy carbon electrode (GCE). Light irradiation on the GCE surface induced the formation of hot electron-hole pairs. In alkaline solutions, hot holes can oxidize hydroxide anions to hydroxyl radicals that are capable of promoting the oxidation of luminol to generate larger current and stronger ECL. Moreover, the stability of current and ECL is also significantly improved upon light irradiation. This study provides a simple method to enhance the electrochemistry and ECL of luminol that have promise in improving the sensitivity of luminol-based chemical analysis and bioanalysis.
关键词： light irradiation,electrochemiluminescence,glassy carbon electrode,luminol,hot hole
更新于2025-09-10 09:29:36
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Dopants Control of Electron-Hole Recombination in Cesium-Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Co-Doping Supersedes Mono-Doping
摘要： Using nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory, we simulate electron-hole recombination in pristine and doped inorganic Pb-free double perovskite Cs2TiBr6. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite they do not change the fundamental bandgap of Cs2TiBr6, they decrease the NA electron-phonon coupling and accelerate decoherence, arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants respectively, suppressing electron-hole recombination. More importantly, co-doping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by co-doping in design of high performance all-inorganic Pb-free perovskite solar cells.
关键词： Co-doping,Electron-Hole Recombination,Mono-doping,Energy Conversion and Storage,Cesium-Titanium Halide Double Perovskite,Plasmonics and Optoelectronics,Time Domain Ab Initio Simulation,Dopants Control
更新于2025-09-10 09:29:36
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Validation of sensor for postoperative positioning with intraocular gas
摘要： Purpose: Surgical repair of retinal attachment or macular hole frequently requires intraocular gas. This necessitates specific postoperative positioning to improve outcomes and avoid complications. However, patients struggle with correct positioning. We have developed a novel sensor to detect the position of the gas bubble in the eye and provide feedback to patients in real time. In this paper, we determine the specificity and sensitivity of our sensor in vitro using a model eye. Methods: We assessed the reliability of our sensor to detect when a gas bubble has deviated off a model retinal break in a model eye. Various bubble sizes representing the intraocular kinetics of sulfur hexafluoride gas and varying degrees of deviation from the correct position were tested using the sensor attached to a mannequin head with a model eye. Results: We recorded 36 data points. The sensor acted appropriately in 33 (91.7%) of them. The sensor triggered the alarm every time the bubble deviated off the break (n=15, sensitivity =100%). However, it triggered the alarm (falsely) 3/21 times when the bubble was correctly positioned over the retinal break (specificity =86%). Conclusion: Our device shows excellent sensitivity (100%) and specificity (86%) in detecting whether intraocular gas is tamponading a retinal break in a model eye.
关键词： vitrectomy,retinal detachment,intraocular gas,postoperative positioning,macular hole,pneumatic retinopexy
更新于2025-09-09 09:28:46
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Theoretical study of charge-transport and optical properties of indeno[1,2- <i>b</i> ]fluorene-6,12-dione-based semiconducting materials
摘要： The conducting and optical properties of a series of indeno[1,2-b]fluorene-6,12-dione (IFD)-based molecules have been systematically studied and the influences of butyl, butylthio and dibutylamino substituents on the reorganization energies, intermolecular electronic couplings and charge-injection barriers of IFD have been discussed. The quantum-chemical calculations combined with electron-transfer theory reveal that the incorporation of sulfur-linked side chains decreases reorganization energy associated with hole transfer and optimizes intermolecular π–π stacking, which results in excellent ambipolar charge-transport properties (μh = 1.15 cm2 V?1 s?1 and μe = 0.08 cm2 V?1 s?1); in comparison, addition of dibutylamino side chains increases intermolecular steric interactions and hinders perfect intermolecular π–π stacking, which results in the weak electronic couplings and finally causes the low intrinsic hole mobility (μh = 0.01 cm2 V?1 s?1). Furthermore, electronic spectra of butyl-IFD, butylthio-IFD and dibutylamino-IFD were simulated and compared with the reported experimental data. Calculations demonstrate that IFD-based molecules possess potential for developing novel infrared and near-infrared probe materials via suitable chemical modifications.
关键词： intrinsic electron mobility,structure–function relationship,indeno[1,2-b]fluorene-6,12-dione-based molecules,density functional theory (DFT),intrinsic hole mobility,electronic spectra
更新于2025-09-09 09:28:46
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Foveal microstructure and visual outcomes of myopic macular hole surgery with or without the inverted internal limiting membrane flap technique
摘要： Purpose The aim of this study was to determine the effect of the inverted internal limiting membrane (ILM) flap technique on the macular hole (MH) closure and foveal microstructure recovery of patients with highly myopic MH. Methods Pars plana vitrectomy and gas tamponade with the inverted ILM flap technique (19 eyes) or with the ILM peeling technique (21 eyes) were performed in patients with highly myopic MH with or without retinal detachment. The rate of MH closure and retinal reattachment, the reconstructive anatomical change of the foveal microstructure and the best-corrected visual acuities (BCVA) of the two groups were compared. results The anatomic closure rate was statistically significantly higher in the inverted group (100%) than in the peeling group (66.7%; p=0.009). All eyes with MH retinal detachment had successful retinal reattachment in these two groups. However, the rate of the external limiting membrane (ELM) and ellipsoid zone (EZ) (p=0.020), as well as gliosis (p=0.049) in macular area, detected by OCT, was significantly greater in the inverted group than in the peeling group. The postoperative BCVA was significantly better in the eyes with ELM, EZ (p=0.031) and gliosis (p=0.008), but without hyperreflective foci (p=0.001). Conclusions These findings demonstrate that the inverted ILM flap technique has better efficacy than the ILM peeling technique for patients with myopic MH in closure rate, foveal microstructure and postoperative BCVA.
关键词： foveal microstructure,myopic macular hole,ILM peeling technique,visual outcomes,inverted internal limiting membrane flap technique
更新于2025-09-09 09:28:46
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A review on low-molar-mass carbazole- based derivatives for organic light emitting diodes
摘要： Organic light emitting diodes (OLEDs) have attracted a great deal of attention within academia and industry because of their potential applications in flat panel displays and solid-state lighting technologies. Among all low-molar-mass derivatives under investigation in OLEDs field, carbazole-based materials have been studied at length for their interesting physical properties, including good charge injection and transport, electro-luminescence, improved thermal and morphological stabilities as well as film forming properties. In addition, the relatively high triplet energy level of some substituted carbazoles makes them suitable candidates to design hosts for wide bandgap triplet emitters such as blue dopants. The article is written from structural organic chemist's point of view and is divided in several parts: V-shaped 3(2)-substituted carbazoles and derivatives with 9-carbazolyl rings, star-shaped 3,6(2,7)-substituted carbazoles and branched twin derivatives containing (di)arylcarbazolyl fragments.
关键词： Amorphous material,Ionization potential,Glass transition temperature,Organic light emitting diode,Substituted carbazole,Hole transporting material
更新于2025-09-09 09:28:46
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Modeling charge density in AlGaN/AlN/InGaN/GaN-based double heterostructures including InGaN layer strain relaxation
摘要： An analytical model is presented to calculate the two-dimensional electron gas (2DEG) density and barrier height of bare surface AlGaN/AlN/InGaN/GaN double heterostructures, which use InGaN as the conducting layer. The basic model is derived from electrostatic analysis of the di?erent material interfaces. The e?ect of strain relaxation in the InGaN layer is also incorporated here. Further, the impact of a two-dimensional hole gas at the InGaN/GaN interface, formed when the InGaN layer thickness is high, has been considered. The presented results are seen to agree with the available experimental results. Thus, this model can be a useful tool in the design and modeling of InGaN-based III-nitride heterostructures.
关键词： two-dimensional hole gas,AlGaN/InGaN/GaN heterostructure,strain relaxation,two-dimensional electron gas
更新于2025-09-09 09:28:46
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Highly Selective Oxidation of Glycerol over Bi/Bi3.64Mo0.36O6.55 Heterostructure: Dual Reaction Pathways Induced by Photogenerated 1O2 and Holes
摘要： Selective oxidation of glycerol to produce aimed high-value added products is of great importance in chemical industry. Photocatalytic oxidation provides a promising and green strategy for selective glycerol oxidation. In this work, we develop a Bi/Bi3.64Mo0.36O6.55 heterostructure via a facile solvothermal method for the selective oxidation glycerol to 1, 3-dihydroxyacetone (DHA) in water under visible light irradiation. The excellent performance in activity and selectivity of Bi/Bi3.64Mo0.36O6.55 heterostructure for DHA production is attributed to a dual-pathway photocatalytic reaction process. The mass production 1O2 ascribed to the reduced energy gap (ΔEST), the enhanced spin-orbit coupling (SOC) and the presence of oxygen vacancy is beneficial for the selective oxidation of glycerol to DHA. Simultaneously, the metallic bismuth in the heterostructure promotes the separation of photogenerated holes with efficient redox potential and facilitates the binding bismuth with ortho-hydroxyl in glycerol, thus enhancing the yield and selectivity of DHA production. This work provides a novel strategy and thorough understanding of the development of highly efficient bismuth-based photocatalyst for selective oxidation in organic reactions.
关键词： Photogenerated hole,Bi/Bi3.64Mo0.36O6.55,Glycerol,1O2,Selective oxidation
更新于2025-09-09 09:28:46
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Highly c-axis oriented crystal growth induced giant unusual saturable absorption behavior in wet chemically grown ZnO thin films
摘要： Wet-chemical sol-gel spin coating technique was considered to fabricate ZnO thin films on bare glass substrates with different thickness values (30 nm, 90 nm, 110 nm, 150 nm). The XRD reflections showed a transition from semi-polar crystal growth orientation to polar crystal growth orientation when the thickness was reduced to 30 nm. The nonlinear characteristics of prepared nano-films were quantized by performing open aperture and closed aperture Z-scan measurements under a continuous wavelength regime. The open aperture Z-scan transmittance curves showed a remarkable transition from normalized valley to normalized peak in 30 nm thick ZnO film. The presence of normalized valley and peak were attributed to reverse saturable absorption (RSA) and saturable absorption (SA) behavior respectively. The RSA behavior was attributed to well known two-photon absorption (TPA) mechanisms and the SA behavior was due to the reduction in electron-hole wave function overlapping along c-axis. The closed aperture Z-scan measurement of 30 nm thick ZnO film revealed the violation of two parabolic band (TPB) and Kramer-Kronig relations by exhibiting self-focusing mechanism. The self-focusing mechanism was attributed to thermal effects due to the smaller thickness of ZnO. However, self-defocusing behavior was observed in 90 nm, 110 nm, and 150 nm thick ZnO films.
关键词： electron-hole wavefunction,saturable absorption,polar ZnO,thermo-optic effect,self-focusing
更新于2025-09-09 09:28:46