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Excellent exciton luminescence of CsPbI3 red quantum dots in borate glass
摘要： We have fabricated CsPbI3 perovskite quantum dots in a borate glass by melt-quenching technique. Three representative samples with different treatment conditions are investigated. As treatment condition enhances, energy gap is extracted as 1.75-1.76eV, and photoluminescence peak is adjustable from 675 to 691nm. Full width at half-maximum (FWHM) varies from 43 to 37 nm. PL intensity first increases and then decreases with increasing excitation wavelength, but the peak wavelength and line-shape are independent. High PLQY values of 23.8%-61.4% are obtained. The high PLQY values are attributed to good crystal quality and less energy dissipation. PL lifetime is fitted as 24.0-28.2ns and 100.2-123.0ns for short and long lifetime components in bi-exponential function. For temperature from 25 to 125 oC, PL intensity decreases, but it is reversible. Exciton binding energy is extracted in the level of 375-454meV. The FWHM broadening from 39 to 49nm and peak blue-shift from 690 to 685nm are investigated.
关键词： Photoluminescence quantum yield,Lifetime,CsPbI3,Temperature dependence,Quantum dots glass,Exciton
更新于2025-11-14 15:23:50
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Uncertainty budgets of major ozone absorption cross sections used in UV remote sensing applications
摘要： Detailed uncertainty budgets of three major ultraviolet (UV) ozone absorption cross-section datasets that are used in remote sensing application are provided and discussed. The datasets are Bass–Paur (BP), Brion–Daumont–Malicet (BDM), and the more recent Serdyuchenko–Gorshelev (SG). For most remote sensing application the temperature dependence of the Huggins ozone band is described by a quadratic polynomial in temperature (Bass–Paur parameterization) by applying a regression to the cross-section data measured at selected atmospherically relevant temperatures. For traceability of atmospheric ozone measurements, uncertainties from the laboratory measurements as well as from the temperature parameterization of the ozone cross-section data are needed as input for detailed uncertainty calculation of atmospheric ozone measurements. In this paper the uncertainty budgets of the three major ozone cross-section datasets are summarized from the original literature. The quadratic temperature dependence of the cross-section datasets is investigated. Combined uncertainty budgets is provided for all datasets based upon Monte Carlo simulation that includes uncertainties from the laboratory measurements as well as uncertainties from the temperature parameterization. Between 300 and 330 nm both BDM and SG have an overall uncertainty of 1.5 %, while BP has a somewhat larger uncertainty of 2.1 %. At temperatures below about 215 K, uncertainties in the BDM data increase more strongly than the others due to the lack of very low temperature laboratory measurements (lowest temperature of BDM available is 218 K).
关键词： uncertainty budgets,Monte Carlo simulation,temperature dependence,UV remote sensing,ozone absorption cross sections
更新于2025-09-23 15:21:21
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[IEEE 2020 IEEE 20th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF) - San Antonio, TX, USA (2020.1.26-2020.1.29)] 2020 IEEE 20th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF) - Progress Towards Fully On-Chip Frequency-Stabilization for Sub-Terahertz Sources
摘要： Resonators fabricated in heavily doped silicon have been noted to have a reduced frequency-temperature dependence compared with lightly doped silicon. The resonant frequency of silicon microelectromechanical systems (MEMS) resonators is largely governed by the material’s elastic properties, which are known to depend on doping. In this paper, a suite of different types and orientations of resonators were used to extract the ?rst- and second-order temperature dependences of the elastic constants of p-doped silicon up to 1.7e20 cm?3 and n-doped up to 6.6e19 cm?3. It is shown that these temperature-dependent elastic constants may be used in ?nite element analysis to predict the frequency-temperature dependence of similarly doped silicon resonators.
关键词： temperature dependence,Doping,resonators,silicon
更新于2025-09-23 15:21:01
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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) - Room Temperature Wet Chemical Growth of an Oxygen Enhanced Diffusion Oxide Utilized in a Boron Diffusion Process
摘要： Resonators fabricated in heavily doped silicon have been noted to have a reduced frequency-temperature dependence compared with lightly doped silicon. The resonant frequency of silicon microelectromechanical systems (MEMS) resonators is largely governed by the material’s elastic properties, which are known to depend on doping. In this paper, a suite of different types and orientations of resonators were used to extract the ?rst- and second-order temperature dependences of the elastic constants of p-doped silicon up to 1.7e20 cm?3 and n-doped up to 6.6e19 cm?3. It is shown that these temperature-dependent elastic constants may be used in ?nite element analysis to predict the frequency-temperature dependence of similarly doped silicon resonators.
关键词： temperature dependence,Doping,resonators,silicon
更新于2025-09-23 15:21:01
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Understanding Temperature-Dependent Charge Extraction and Trapping in Perovskite Solar Cells
摘要： Understanding the factors that limit the performance of perovskite solar cells (PSCs) can be enriched by detailed temperature (T)-dependent studies. Based on p-i-n type PSCs with prototype methylammonium lead triiodide (MAPbI3) perovskite absorbers, T-dependent photovoltaic properties are explored and negative T-coefficients for the three device parameters (VOC, JSC, and FF) are observed within a wide low T-range, leading to a maximum power conversion efficiency (PCE) of 21.4% with an impressive fill factor (FF) approaching 82% at 220 K. These T-behaviors are explained by the enhanced interfacial charge transfer, reduced charge trapping with suppressed nonradiative recombination and narrowed optical bandgap at lower T. By comparing the T-dependent device behaviors based on MAPbI3 devices containing a PASP passivation layer, enhanced PCE at room temperature is observed but different tendencies showing attenuating T-dependencies of JSC and FF, which eventually leads to nearly T-invariable PCEs. These results indicate that charge extraction with the utilized all-organic charge transporting layers is not a limiting factor for low-T device operation, meanwhile the trap passivation layer of choice can play a role in the T-dependent photovoltaic properties and thus needs to be considered for PSCs operating in a temperature-variable environment.
关键词： temperature dependence,charge trapping,recombination,charge extraction,passivation layer
更新于2025-09-23 15:21:01
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Size and Temperature Dependent Intraband Optical Properties of Heavily <i>n-</i> Doped PbS Colloidal Quantum Dot Solid-State Films
摘要： Steady-state access to intraband transitions in colloidal quantum dots (CQDs), via doping, permits exploitation of the electromagnetic spectrum at energies below the band gap. CQD intraband optoelectronics allows envisaging cheap mid- and long-wavelength infrared photodetectors and light-emitting devices, which today employ epitaxial materials. As intraband devices start to emerge, thorough studies of the basic properties of intraband transitions in different CQD materials are needed to guide technological research. In this work, we investigate the size and temperature dependence of the intraband transition in heavily n-doped PbS quantum dot (QD) films. In the studied QD size range (5–8 nm), the intraband energy spans from 209 meV to 151 meV. We measure the intraband absorption coefficient of heavily doped PbS QD films to be around 2 × 104 cm-1, proving that intraband absorption is as strong as interband absorption. We demonstrate a negative dependence of the intraband energy with temperature, in contrast to the positive dependence of the interband transition. Also opposite to the interband case, the temperature dependence of the intraband energy increases with decreasing size, going from -29 μeV/K to -49 μeV/K in the studied size range.
关键词： temperature dependence,absorption coefficient,intraband,lead sulphide,quantum dots
更新于2025-09-23 15:21:01
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Scintillation response to gamma-rays measured at wide temperature range for Tl doped CsI with SiPM readout
摘要： A custom design cryostat was constructed to study the temperature dependence of relative light yield and non-proportionality trends of scintillators between –182oC and +152oC. CsI:Tl crystal response to γ-rays and X-rays was investigated between 14 keV and 662 keV. Scintillation light was detected by a SiPM device, which was installed on a copper frame separated from the crystal and the cooling rod to enable operating the device at room temperature. The scintillation efficiency of CsI:Tl is peaked at about room temperature. The light yield of CsI:Tl at temperature close to liquid nitrogen boiling point is reduced by a factor of 15 in comparison to room temperature conditions. The non-proportionality of CsI:Tl scintillation response is high at low temperatures and is getting more proportional with increasing temperature.
关键词： photoelectron yield,temperature dependence,non-proportionality,CsI:Tl
更新于2025-09-23 15:21:01
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Thermal characterization of a silicone-on-glass micro aspheric lens array for a concentrator photovoltaic module
摘要： This study examined the effects of the thermal deformation of a silicone-on-glass (SOG) micro aspheric lens on the optical performance of a concentrator photovoltaic (CPV) module. Thermal deformation of the lens induced by temperature variation causes defocalization of the spot of concentrated light on the solar cell, resulting in a change in the optical efficiency and irradiance uniformity in the solar cell area. The irradiance uniformity affects the fill factor of the solar cell. The effects of the thermal deformation of the lens on the optical efficiency and irradiance uniformity in the solar cell area were evaluated through a three-dimensional thermal deformation simulation and ray-tracing simulation. The simulation methods were validated by indoor heating tests using a prototype SOG lens and III–V triple-junction solar cell. The simulation results for optical systems with geometric concentration ratios of 200 ? and 500 ? revealed that the temperature dependences of the optical performances of a system with SOG micro aspheric lenses showed similar trends to those of a system with SOG Fresnel lenses designed with the same lens surface profiles as aspheric lenses.
关键词： Optical efficiency,Temperature dependence,Microscale concentrator photovoltaics,Plano-convex aspheric lens,Silicone-on-glass lens
更新于2025-09-23 15:19:57
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Mass Accommodation Coefficients of Water on Organics from Complementary Photoacoustic and Light Scattering Measurements on Laser-Trapped Droplets
摘要： The mass accommodation coefficient, αM, describes the liquid?vapor evaporation and condensation kinetics at interface. In spite of numerous experimental efforts, reliable values of αM are still not available for many substances. Here, we present a novel experimental technique, photothermal single-particle spectroscopy (PSPS), that allows for a robust retrieval of mass accommodation coefficients from three simultaneous independent measurements. PSPS combines resonant photoacoustic absorption spectroscopy with modulated Mie scattering measurements on single particles. We study the mass transport of water on organic aerosol droplets that are optically trapped using counter-propagating tweezers. We find the mass accommodation coefficient of water on a pure model organic that is fully miscible with water to be 0.021 at 296 K and to decrease by more than an order of magnitude when the temperature increases to 309 K. The experimentally observed temperature dependence of αM shows an Arrhenius behavior. Furthermore, the water content of the droplets is found to have a profound effect on αM is observed at low water concentrations, while at elevated water concentrations, we observe a 5-fold increase in αM. The technique presented in this work has the potential to become a reliable method for the retrieval of αM values at liquid?vapor interfaces, which are essential for accurate global climate and pharmaceutical aerosol inhalation modeling, to mention but a few.
关键词： temperature dependence,photoacoustic absorption spectroscopy,optical trapping,water transport,organic aerosol droplets,modulated Mie scattering,mass accommodation coefficient,Arrhenius behavior,PSPS,photothermal single-particle spectroscopy
更新于2025-09-23 15:19:57
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Energy transfer and luminescence quenching of Cr3+-doped LiGaW2O8
摘要： Luminescence properties of the Cr3+-doped LiGaW2O8 crystals are investigated by laser excitation spectroscopy. The powder samples for various Cr3+ concentration were prepared by high-temperature solid state reaction. The temperature behaviors of the emission intensity and the decay time of the self-activated LiGaW2O8 host are discussed. The emission spectra and decay times of LiGa1-xW2O8:xCr3+ are measured under UV excitation in the temperature range 10 - 300 K. The luminescence quenching of LiGaW2O8:Cr3+ as functions of temperature and Cr3+-concentration is explained by structural and spectral characteristics.
关键词： luminescence quenching,temperature dependence.,energy transfer
更新于2025-09-19 17:15:36