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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Correlative Microscopy Characterization of Cesium-Lead-Bromide Thin-films
摘要： Inorganic cesium lead halide compounds have gained an increasing interest in the perovskite photovoltaics research community. These compounds are mixed into state of the art organic lead halide perovskite solar cells to provide for more thermal stability, and CsPbX3 (x=I, Br, Cl) nanocubes are investigated as standalone emitter material in light emitting diodes. Eventually, reproducible, single-phase CsPbBr3 thin films could also provide us with a more stable inorganic material for perovskite solar cells. In the present work, we report on microscopic structural and optoelectronic properties of Cs-Pb-Br thin films prepared by different synthesis methods and studied using various electron-microscopy techniques.
关键词： cesium lead bromide,secondary phases,phase distribution,correlative microscopy,electron microscopy,halide Perovskites
更新于2025-11-21 10:59:37
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Tailoring optical cross sections of gold nanorods at a target plasmonic resonance wavelength using bromosalicylic acid
摘要： In many applications, the optical cross sections of gold nanorods (AuNRs) are required to be tailored at a fixed target longitudinal surface plasmon resonance (LSPR) wavelength depending on the excitation source and the photodetector. In this work, we demonstrate the fine tailoring of optical cross sections of AuNRs at a fixed target resonance wavelength, on the basis of AuNR overgrowth using a binary surfactant mixture consisting of 5-bromosalicylic acid (BSA) and cetyltrimethylammonium bromide (CTAB). A systematic study was performed on the sum effects of the BSA concentration and the volume of the growth solution, which gives a formula for quantitative instructions. Based on the formula, we gave examples for the successful synthesis of AuNRs with different optical cross sections at target LSPR wavelengths. From simulation, a nonlinear relationship was further derived to understand the relationship between the aspect ratio and the width of the AuNRs at a target LSPR wavelength for the dimension design of AuNRs. The ratio of optical against physical cross sections was calculated and plotted as a function of the width. The results clearly indicate that AuNRs with a width of 30 nm possess the highest efficiency in terms of optical per physical cross section. Our study provides reliable methods for the synthesis, as well as guidelines for the dimension design of AuNRs, for use in a variety of applications.
关键词： 5-bromosalicylic acid,gold nanorods,optical cross sections,cetyltrimethylammonium bromide,surface plasmon resonance
更新于2025-11-19 16:56:42
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Achieving a high open-circuit voltage in inverted wide-bandgap perovskite solar cells with a graded perovskite homojunction
摘要： Wide-bandgap (~1.7-1.8 eV) perovskite solar cells have attracted substantial research interest in recent years due to their great potential to fabricate efficient tandem solar cells via combining with a lower bandgap (1.1-1.3 eV) absorber (e.g., Si, copper indium gallium diselenide, or low-bandgap perovskite). However, wide-bandgap perovskite solar cells usually suffer from large open circuit voltage (Voc) deficits caused by small grain sizes and photoinduced phase segregation. Here, we demonstrate that in addition to large grain sizes and passivated grain boundaries, controlling interface properties is critical for achieving high Voc’s in the inverted wide-bandgap perovskite solar cells. We adopt guanidinium bromide solution to tune the effective doping and electronic properties of the surface layer of perovskite thin films, leading to the formation of a graded perovskite homojunction. The enhanced electric field at the perovskite homojunction is revealed by Kelvin probe force microscopy measurements. This advance enables an increase in the Voc of the inverted perovskite solar cells from an initial 1.12 V to 1.24 V. With the optimization of the device fabrication process, the champion inverted wide-bandgap cell delivers a power conversion efficiency of 18.19% and sustains more than 72% of its initial efficiency after continuous illumination for 70 h without encapsulation. Additionally, a semitransparent device with an indium tin oxide back contact retains more than 88% of its initial efficiency after 100 h maximum power point tracking.
关键词： wide-bandgap perovskite solar cells,perovskite homojunction,guanidinium bromide
更新于2025-10-22 19:40:53
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3D graphene/AgBr/Ag cascade aerogel for efficient photocatalytic disinfection
摘要： To design semiconductor-based photocatalysts with efficient charge carriers separation and transfer remains an enduring goal of artificial photosynthesis toward target redox reactions. Herein, we report a cascade monolith composite of ternary reduced graphene oxide aerogel/silver bromide/silver (RGA/AgBr/Ag) with efficient charge carriers separation, which exhibits much higher activity than bare AgBr toward photocatalytic bacteria inactivation. Mechanistic studies reveal that the reduced graphene oxide aerogel (RGA) scaffold and Ag nanoparticles serve as electron relay mediators to promote the charge carriers separation and transfer. In addition, the metallic Ag nanoparticles derived from the photoreduction of AgBr during the photocatalytic disinfection can further boost the separation of charge carriers. Control experiments demonstrate that the surface plasmon resonance (SPR)-excited hot electrons of Ag nanoparticles also contributes to enhancing the photoactivity of RGA/AgBr/Ag. As such, the synergy of multiple electron transfer behavior integratively leads to the boosted photocatalytic performance of such RGA/AgBr/Ag aerogel for bacteria inactivation with convenient recyclable operability.
关键词： charge transfer,aerogel,silver bromide,Ag nanoparticles,reduced graphene oxide
更新于2025-09-23 15:23:52
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Doping induced dielectric anomaly below the Curie temperature in molecular ferroelectric diisopropylammonium bromide
摘要： A dielectric anomaly induced by doping has been observed at about 340 K in chlorine-doped diisopropylammonium bromide. The dielectric anomaly has a switchable behaviour, which indicates potential applications on switches and sensors. Temperature-dependent Raman spectrum, X-ray diffraction and differential scanning calorimetry do not show any anomaly around the dielectric anomaly temperature, which prove that the dielectric anomaly does not come from structure phase transition and has no specific heat variety. It is assumed that this dielectric anomaly can be attributed to the freezing of ferroelectric domain walls induced by the pinning of point defects.
关键词： diisopropylammonium bromide,molecular ferroelectric,doping,dielectric anomaly
更新于2025-09-23 15:23:52
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Effect of photochemical advanced oxidation processes on the formation potential of emerging disinfection by-products in groundwater from part of the Pannonian Basin
摘要： This study evaluates the effect of photochemical advanced oxidation processes (AOPs) (O3/UV, H2O2/UV and O3/H2O2/UV) on the formation potential (FP) of emerging disinfection by-products including nitrogenous by-products (N-DBPs) and haloketones (HKs) in groundwater from part of the Pannonian Basin (AP Vojvodina, Republic of Serbia). Among the N-DBPs, the haloacetonitrile (HAN) precursor contents were 9.83 ± 0.59 μg/L while precursors of halonitromethanes, particularly trichloronitromethane (TCNM) were not detected. Similarly, precursors of HKs as carbonaceous DBPs were also not detected in raw water. Ozonation alone and H2O2/UV process with a lower UV dose maximally decomposed HAN precursors (about 70%) while during O3 based AOPs, HANFP varied significantly. Application of UV photolysis and H2O2/UV processes with increasing UV dose doubled the HANFP. Ozone alone, O3/UV and H2O2/UV slightly increased HKs formation potential, particularly 1,1-Dichloro-2-propanone FP (0.93 ± 0.21 to 2.01 ± 0.37 μg/L). None of the investigated treatments influenced the formation of TCNM precursors. The effect of the applied treatments on bromide incorporation was the most evident for HANs.
关键词： emerging disinfection by-products,ozone,bromide incorporation,photochemical advanced oxidation processes
更新于2025-09-23 15:23:52
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Role of electron and hole centers in energy transfer in BaBrI crystals
摘要： In this paper we study a role of F-centers, hole centers and excitons in energy transfer in Eu-doped BaBrI crystals. Optical absorption spectra, thermally stimulated (TSL) and photostimulated (PSL) luminescence in wide temperature range 7-300 K are studied in undoped and doped with different concentrations of Eu ions BaBrI crystals. Based on experimental and calculated results two possible energy tranfer processes from host to Eu2+ ions are established.
关键词： energy transfer,thermoluminescence,alkali earth halides,scintillators,bromide,iodide,F-center,photostimulated luminescence
更新于2025-09-23 15:22:29
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Photocatalytic degradation of azophloxine on porous La2Ti2O7 prepared by sol-gel method
摘要： Cetyltrimethyl ammonium bromide (CTAB) was used in a sol-gel route to synthesize porous lanthanum titanate. The materials are composed of perovskite La2Ti2O7 in monoclinic system. The addition of CTAB does not cause phase transformation, but leads to a slight decreasing tendency of La2Ti2O7 crystallite size. Both the pore volume and pore size distribution range are enlarged after using CTAB. The sample obtained with 4 g CTAB has the maximum BET specific surface area of 42.4 m2/g. When the amount of CTAB is less than 4 g, the increase in photocatalytic degradation efficiency is almost in linear relationship to the amount of CTAB. The reaction rate constants are 0.0032, 0.0116 and 0.0237 min-1 on the La2Ti2O7 samples obtained using 0, 2 and 4 g CTAB. The functional groups in azophloxine molecule are decomposed during photocatalytic oxidation with extending irradiation time.
关键词： cetyltrimethyl ammonium bromide,azophloxine,degradation,photocatalysis,lanthanum titanate
更新于2025-09-23 15:21:21
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Characterization and application of cerium bromide spectrometers for analysis of γ-ray emitting radionuclides in food matrices
摘要： Cerium bromide (CeBr3) scintillators are useful room temperature gamma-ray detectors that provide the robustness of a scintillator with improved resolution over traditional sodium iodide (NaI) detectors. This makes them attractive for field deployment or emergency response operations especially when combined with the power of Monte-Carlo based efficiency determinations. This work documents the characterization of CeBr3 detectors and the efficiency determination of a portable CeBr3 detector based gamma-ray detection system for food measurements.
关键词： Gamma-ray measurement,Cerium bromide,Efficiency calculation,Food safety
更新于2025-09-23 15:21:21
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Highly Efficient and Stable GABr-Modified Ideal-Bandgap (1.35 eV) Sn/Pb Perovskite Solar Cells Achieve 20.63% Efficiency with a Record Small <i>V</i> <sub/>oc</sub> Deficit of 0.33 V
摘要： 1.5–1.6 eV bandgap Pb-based perovskite solar cells (PSCs) with 30–31% theoretical efficiency limit by the Shockley–Queisser model achieve 21–24% power conversion efficiencies (PCEs). However, the best PCEs of reported ideal-bandgap (1.3–1.4 eV) Sn–Pb PSCs with a higher 33% theoretical efficiency limit are <18%, mainly because of their large open-circuit voltage (Voc) deficits (>0.4 V). Herein, it is found that the addition of guanidinium bromide (GABr) can significantly improve the structural and photoelectric characteristics of ideal-bandgap (≈1.34 eV) Sn–Pb perovskite films. GABr introduced in the perovskite films can efficiently reduce the high defect density caused by Sn2+ oxidation in the perovskite, which is favorable for facilitating hole transport, decreasing charge-carrier recombination, and reducing the Voc deficit. Therefore, the best PCE of 20.63% with a certificated efficiency of 19.8% is achieved in 1.35 eV PSCs, along with a record small Voc deficit of 0.33 V, which is the highest PCE among all values reported to date for ideal-bandgap Sn–Pb PSCs. Moreover, the GABr-modified PSCs exhibit significantly improved environmental and thermal stability. This work represents a noteworthy step toward the fabrication of efficient and stable ideal-bandgap PSCs.
关键词： ideal bandgap,perovskite solar cells,mixed tin–lead perovskites,guanidinium bromide,molecular doping
更新于2025-09-23 15:21:01