Stable Cesium Research Articles

Investigating the association between dry deposition of cesium and different growth stages of aboveground parts of Chinese yam.

Radiocesium released into the atmosphere from accidents at nuclear facilities, can be deposited on the surface of the surrounding crop fields as dry and wet deposits. Radiocesium deposition can occur at any time during the growth season. In this study, we used stable cesium (Cs) to investigate the changes in dry Cs deposits on surfaces of aboveground parts of Chinese yam (Dioscorea polystachya) during different growth stages. Chinese yam seedlings were grown for eight different lengths of time and were then simultaneously exposed to aerosol particles containing stable Cs in an aerosol exposure chamber for 5h. The deposition density of Cs on the aboveground parts of the seedlings decreased from 29 to 72d after transplantation (DAT) and did not change significantly after 72 DAT. The Cs deposition density on the seedlings on different DAT correlated with the leaf area available for the deposition of aerosol Cs particles.

Lead-free Cs2TiBr6 perovskite solar cells achieving high power conversion efficiency through device simulation

Recently, lead-based perovskite solar cells (PSCs) have gained significant attention in the photovoltaic industry due to their remarkable properties such as high bandgap and high absorption coefficient. However, challenges such as toxicity, instability, and short shelf life limit the use of inorganic-organic lead-based PSCs. To address these issues, researchers introduced eco-friendly, lead-free, and stable cesium titanium (Cs2TiBr6) single-halide absorber material. The aim of this work is to perform the numerical modelling and simulation of FTO/SnO2/Cs2TiBr6/CBTS/Au structure incorporating interfacial defect layers (IDL) using SCAPS-1D to examine and study its characteristics properties about various photovoltaic (PV) parameters such as light-absorbing layer thickness, charge transport layer thickness, doping, defect density, operating temperature, and quantum efficiency (QE). After evaluating these parameters, the proposed single-halide Cs2TiBr6-based structure shows superior performance as compared to previously reported experimental and simulation-based Cs2TiBr6 perovskite structures. The results show a maximum power conversion efficiency (PCE) of 24.24 %, with a fill factor (FF) of 88.9 %, an open-circuit voltage (VOC) of 1.31 V, and a short-circuit current density (JSC) of 20.76 mA/cm2. This work encourages researchers to develop low-toxic, and stable PSCs for the future solar cell industry.

Characterisation and analysis of soil properties and trace elements in agricultural soils of Rabat-Sale-Kenitra, Morocco: focus on stable strontium and caesium

ABSTRACT This study explores strontium (Sr) and caesium (Cs) dynamics in Moroccan agricultural soils, focusing on contaminant impacts and soil properties. Soil samples from El Koudia, Merchouch, and El Guich exhibit different textures: clayey (Merchouch), sandy clay loam (El Koudia), and sandy (El Guich). Chemical analysis shows consistent pH, with %CaCO3 at 1%, 4%, and 6%, and organic matter content at 4.5%, 1.1%, and 3.3% in Merchouch, El Guich, and El Koudia, respectively. Cation exchange capacity (CEC) and levels of Ca, K, Na, Mn, and Fe were measured. X-ray diffraction (XRD) identified quartz as the main mineral, with site-specific variations. X-ray fluorescence spectrometry (XRF) indicated consistent Cr, Ni, Cu, Zn, As, and Pb levels, and Rb varied significantly. Sr concentrations were 0.17 ppm in El Koudia and Merchouch, and 0.32 ppm in El Guich. Cs was undetected. This research highlights complex soil properties, elemental composition, and contaminant distribution in agricultural soils.

Dual-frequency optical-microwave atomic clocks based on cesium atoms

133Cs, the only stable cesium (Cs) isotope, is one of the most investigated elements in atomic spectroscopy and was used to realize the atomic clock in 1955. Among all atomic clocks, the cesium atomic clock has a special place, since the current unit of time is based on a microwave transition in the Cs atom. In addition, the long lifetime of the 6P3/2 state and simple preparation technique of Cs vapor cells have great relevance to quantum and atom optics experiments, which suggests the use of the 6S−6P D2 transition as an optical frequency standard. In this work, using one laser as the local oscillator and Cs atoms as the quantum reference, we realize two atomic clocks at the optical and microwave frequencies. Both clocks can be freely switched or simultaneously output. The optical clock, based on the vapor cell, continuously operated with a frequency stability of 3.9×10−13 at 1 s, decreasing to 2.2×10−13 at 32 s, which was frequency-stabilized by modulation transfer spectroscopy and estimated by an optical comb. Then, applying this stabilized laser to an optically pumped Cs beam atomic clock to reduce the laser frequency noise, we obtained a microwave clock with a frequency stability of 1.8×10−12/τ, reaching 6×10−15 at 105 s. This study demonstrates an attractive feature for the commercialization and deployment of optical and microwave clocks, and will guide the further development of integrated atomic clocks with better stability. Therefore, this study holds significant practical implications for future applications in satellite navigation, communication, and timing.

Long-term behaviour of Cs-137, Cs-133 and K in beech trees of French forests

In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40–50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.

Reactivity and bioconcentration of stable cesium in a hyperturbid fluvial-estuarine continuum: A combination of field observations and geochemical modeling

Effective, post-accidental management needs an accurate understanding of the biogeochemical behavior of radionuclides in surface environments at a regional scale. Studies on stable isotopes (element homologs) can improve this knowledge. This work focuses on the biogeochemical behavior of stable cesium (Cs) along a major European fluvial-estuarine system, the Gironde Estuary (SW France). We present results obtained from (i) a long-term monitoring (2014–2017) of dissolved (Csd) and particulate (Csp) Cs concentrations at five sites along the freshwater continuum of the Garonne watershed, (ii) Csd and Csp concentrations during four oceanographic campaigns at contrasting hydrological conditions along longitudinal profiles of the estuarine system, (iii) a 24 h cycle of Csp at the estuary mouth, and (iv) a historical trend of Cs bioconcentration in wild oysters at the estuary mouth (RNO/ROCCH, 1984–2017). In addition, we model the partitioning of Cs within the estuarine environment for clay mineral interactions via PhreeqC. At fluvial sites, we observe a geogenic dependence of the Csp and a seasonal variability of Csd, with a downstream increase of the solid-liquid partitioning (log10 Kd values from 3.64 to 6.75 L kg−1) for suspended particulate matter (SPM) < 200 mg L−1. Along the estuarine salinity gradients, Cs shows a non-conservative behavior where fresh SPM (defined as Cs-depleted particles recently put in contact with Csd) act as a Cs sink during both flood and low discharge (drought) conditions. This sorption behavior was explained by the geochemical model, highlighting the relevance of ionic strength, water and SPM residence times. However, at high salinities, the overall log10 Kd value decreases from 6.02 to 5.20 for SPM ∼300–350 mg L−1 due to the Csd oceanic endmember. Despite wild oysters showing low bioconcentration factors (∼1220 L kg−1) at the estuary mouth, they are sensitive organisms to Cs fluxes.

Relationship between stable cesium concentration and body size of Japanese flounder Paralichthys olivaceus and the effect of a size-dependent shift in diet.

To understand the relationship between the radioactive cesium (Cs) concentration in muscle of Japanese flounder Paralichthys olivaceus and the species' biological characteristics (size, sex, and age) under conditions of ecological equilibrium (i.e., distributed among ecosystem components over sufficient time, and with nearly constant ratios of Cs concentration in organisms to the concentration in water) as existed before the accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS), Japan, in 2011, we examined stable Cs, as it is thought to exist in equilibrium in the environment and behave similarly to radioactive Cs in aquatic animals. The concentration of stable Cs in 241 P. olivaceus (range 216-782 mm total length [TL]) collected in Sendai Bay, approximately 90 km north of the FDNPS, in June-July 2015 was expressed as an exponential function with size as an independent variable; the results show the concentration of stable Cs doubled with an increase in TL of 442 mm. Next, to evaluate the cause of the size-dependent change in stable Cs concentration, we examined 909 individuals (200-770 mm TL) collected in September 2013-July 2015 to determine their feeding habit based on size. Analysis of the frequency of occurrence of prey organisms in stomach contents showed that sand lance Ammodytes japonicus (55-180 mm standard length [SL]) was the most consistently consumed across size classes. Analysis on a wet-mass basis showed that A. japonicus and anchovy Engraulis japonicus (65-130 mm SL) were the main food of P. olivaceus sized 200-599 mm TL, whereas chub mackerel Scomber japonicus (120-230 mm SL) and two species of flatfishes (180-205 mm SL) were abundant in the diet of P. olivaceus sized ≥600 mm TL. All these prey items were presumed to have similar concentrations of stable Cs. Based on the above, the effect of diet on the relationship between stable Cs in muscle and fish size was considered negligible. That the diet of P. olivaceus largely did not change with size was also confirmed by C and N stable isotope ratios in P. olivaceus and their prey species. Therefore, the Cs-size relationship is probably determined by changes in the balance between the rate of Cs intake from food and seawater and the excretion rate during growth, both of which change as functions of body mass. Values of stable Cs concentrations among environmental components and animals appear to be a valid indicator for understanding the radioactive Cs distribution in the marine environment and aquatic animals under the equilibrium state, as existed before the 2011 nuclear accident.

Degradation of congo red dye by thermally stable lead-free cesium titanium bromide (CsTiBr3) perovskite nanorods

Degradation of congo red dye by thermally stable lead-free cesium titanium bromide (CsTiBr3) perovskite nanorods

Ecological and toxicological features of the effect of stable cesium on striated muscle tissue (myocardium and skeletal muscles) of mammals

Recently, the risks of radiation danger have significantly increased. This is connected with the start of a full-scale war against Ukraine and the seizure of the Zaporizhzhya NPP by the Russian Federation, which has the second most powerful arsenal of nuclear weapons in the world. The majority of studies devoted to the effect of radioactive radiation on the human body and animals absolutely do not take into account the ecotoxic effect of the carrier and a chemical element. At the same time, the body does not distinguish between radioactive and non-radioactive isotopes of chemical elements and interacts with them during exchange processes. The aim of the work was to study the influence of stable cesium on the microscopic structure of striated muscle tissue, both skeletal and cardiac ones. The results of our research revealed that intensive accumulation of cesium for 24 days occurred in all the examined organs and tissues. In fact, the most intensive accumulative process appeared to be in the heart by 214.9 times and by 695.3 times with skeletal muscles, with a simultaneous decrease in potassium content by 19.2% and 29.1%, respectively, compared to intact rats. We can talk about the presence of two mechanisms of action of cesium on tissues, including striated muscles: as an antagonist of potassium, which concerns the transport system of the latter and as a toxic element that initiates peroxide processes with subsequent modification of membranes and their potassium channels. Functional disturbances in the work of potassium channels of excitable tissues in the repolarization phase occur in the conditions of an increase in intracellular cesium in striated muscles. These disorders can proceed according to the type of acquired "potassium" channelopathies, which in the myocardium can manifest in the form of rhythm disorders, prolonged QT syndrome, etc. This leads to the appearance of significant violations of the histological structure of the examined tissues. Cesium has pronounced damaging effects on both skeletal and cardiac striated muscle tissue, with morphological changes in skeletal and cardiac striated muscle tissue being generally similar. Dystrophic changes in the nuclei and cytoplasm of cardiomyocytes and striated muscles, signs of impaired blood circulation in the microcirculatory channel with the formation of vascular wall edema, destruction of endothelial cells, various types of hemorrhages and lymphohistiocytic infiltration of the stroma of fibers are the consequences of the toxic effect of cesium on tissues. Thus, the results of changes in the histological structure of striated muscles under the action of cesium chloride obtained by us indicate a fairly high cytocidal activity of stable cesium.

Stable and Radioactive Cesium in Natural Environment

Cesium is the heaviest stable alkali metal (with only one stable isotope – 133Cs) and it occurs mainly as a potassium-substituting cation. It is an important trace element in rocks typical for the Earth crust, and its content in biomass is also relatively high compared to those abiogenic elements which are little soluble. Low-cost analytical methods like X-Ray Fluorescence are inadequate to quantify cesium in typical natural samples, so that the usage of ICP-MS (Inductively-Coupled-Plasma Mass Spectrometry) or INAA (Instrumental Neutron Activation Analysis) is necessary. Nevertheless, investigation of the pollution with the radioactive isotope 137Cs, which is an important fission product and can be measured with gamma-ray spectrometry, also contributed to the knowledge of biogeochemistry of cesium. It has been shown that Cs is usually strongly retained in humus (thank to clay minerals), or is cycling intensely within the soil-biomass system, being only slowly removed (at least, this is valid for ecosystems in temperate climate). The results of extensive biomonitoring in Czech coniferous forests (with prevailing spruce) also show that Cs is concentrated in humus (relatively to all other alkali elements) by natural processes.

Highly efficient and stable lead-free cesium copper halide perovskites for optoelectronic applications: A DFT based study

Recently synthesized industrially significant perovskites Cs3Cu2X5 (X=Cl,Br,I) are subjected to a density functional theory (DFT) investigation utilizing the CASTEP code. This study explores various physical features, including structural, optical, thermodynamic, elastic, mechanical, and electronic properties. There is a strong correlation between the optimized structure parameters and the existing experimental data, which demonstrates the reliability of our DFT-based computations. The band structure and density of states (TDOS and PDOS) analysis revealed that all the studied perovskites are direct band gap semiconductors, and Cs3Cu2Br5 has the smallest band gap (2.092 eV). We also discussed the mechanical and cell stability using the Born stability criterion and formation energy, respectively. The mechanical and dynamic stability of each phase is confirmed by the analysis of the elastic constants. According to the computed values of Pugh's and Poisson's ratios as well as Cauchy's pressure, all of the studied compounds are ductile in nature. The study of density of states, total charge density, and Mulliken atomic populations reveal that all the compounds have complex bonding with both ionic and covalent properties. Finally, utilizing the elastic constant data, the Debye temperatures of Cs3Cu2Cl5, Cs3Cu2Br5, and Cs3Cu2I5 have been determined as 82.90 K, 100.00 K, and 80.70 K, respectively. The analysis of thermodynamics (relatively low values of both ΘD and Kmin) as well as optical properties indicate that all the investigated materials have the potential to serve as thermal barrier coating (TBC) materials.

Higher stability and better photoluminescence quantum yield of cesium lead iodide perovskites nanoparticles in the presence of CTAB ligand.

Inorganic halide perovskites, such as CsPbI3, have unique optoelectronic properties which made them promising candidates for several applications.Unfortunately, these perovskites undergo rapid chemical decomposition and transformation into yellow δ-phase. Thus, the synthesis of stable cesium lead iodide perovskites remains an actual challenging field and it is imperative to develop a stabilized black phase for photovoltaic applications. For this purpose, a surfactant ligand was used to control the synthesis of inorganic perovskite CsPbI3 nanoparticles. Herein we demonstrate a new avenue for lead halide perovskites with the addition of either hexadecyltrimethylammonium bromide (CTAB) or silica nanoparticles to maintain in the first place; the stability of the α-CsPbI3 phase, and later on to boost their photoluminescence quantum yield (PLQY). The prepared perovskites were characterized using UV-visible absorption spectroscopy, fluorescence spectroscopy, scanning electron microscopy, thermogravimetric analysis and X-Ray diffraction technique. Results show higher stability of α-CsPbI3 phase and improvement in PLQY % to reach 99% enhancement in presence of CTAB. Moreover, the photoluminescence intensity of CsPbI3 nanoparticles was higher and was maintained for a longer duration in the presence of CTAB.

Retaliation of Alstonia scholaris (L.)R.Br. to caesium and strontium in hydroponics: effect on morpho-physiology and induction of enzymatic defence.

The habitation and environment are affected by the stable isotopes of caesium (Cs) and strontium (Sr), as well as by their radioactive isotopes. The current work gives insight on Alstonia scholaris' capacity to phytoextract stable caesium (Cs) and strontium (Sr), as well as the plant's ability to protect against the toxicity of both elements. Experiments with Cs [0-5mM (CsCl)] and Sr [0-3mM (SrCl2. 6H2O)] dosing in controlled light, temperature, and humidity condition in greenhouse for 21days were undertaken. Cs and Sr accumulation in different plant parts was quantified with atomic absorption spectroscopy (AAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) respectively. Hyper-accumulation capacity for Cs and Sr was estimated with indices like transfer factor (TF) and translocation factors (TrF). The uptake pattern of caesium in Alstonia scholaris is 5452.8-24,771.4mg/kg DW (TF = 85.2-57.6) and in the case of Sr is 1307.4-8705.7mg/kg DW (TF = 85.3-1.46). The findings demonstrated the plant's ability to transfer Cs and Sr to aboveground biomass on the basis of dry weight, with the majority of the metals being deposited in the shoot rather than the root portion of the plant. For Cs and Sr, with increasing concentration, the plants exhibited the enzymatic expression for defence against metal toxicity by free radicals compared to control. Field emission electron microscopy with energy-dispersive spectroscopy (FESEM with EDS) was employed to assess the spatial distribution of Cs and Sr in plant leaf, indicating the accumulation of Cs, Sr, and their homologous components.

Highly stable multi-encapsulated red-emitting cesium lead halide nanocrystals for efficient copper ion detection and imaging in live cells

Recently, cesium lead halide (CsPbX3: X = Cl, Br, I) perovskite nanocrystals (NCs) have shown potentiality in the detection of different heavy metal ions and bioimaging applications for their smaller particle size, tunable emission spectra, high luminescent intensity, narrow emission spectra, multiphoton absorption property, etc. CsPbBr3 NCs are explored extensively in bioimaging applications for their comparatively higher stability in water. A longer wavelength excitation light source is recommended due to less scattering of light results in deeper penetration in living cells. However, imaging in live cells with red-emitting perovskite NCs is not suitable because of their poor structural stability, low emission intensity, and complex synthesis process. To tackle these issues, we introduce a specific halide exchange to the NCs and then multi-encapsulation shelling techniques that eventually improve the structural and environmental stability of the red-emitting NCs. Here, we synthesized Zn-doped CsPbBr3 NCs via the ligand-assisted reprecipitation (LARP) synthesis method in an open atmosphere. Then the highly luminescent red emitting CsPbBrxI3−x NCs with Zn doping were grown via the exchange of halide ions from pre-synthesized Zn-doped CsPbBr3 NCs to maintain the stable perovskite crystal structure in the nanoscale regime. Such NCs were further encapsulated with different shelling materials and then compared their photophysical properties. Among them, n-isopropyl acrylamide passivated Zn-doped CsPbBrxI3−x/SiO2/polyvinylpyrrolidone core/shell/shell NCs showed the highest stability against water and UV-irradiation. These NCs efficiently detect Cu2+-ions in water and achieved a detection limit of around 9.68 µM. The NCs were also tested for their compatibility as a fluorescent probe for live cell imaging using mammalian Chinese Hamster Ovary cells. As a proof-of-principle, we demonstrate both the efficient uptake and biocompatibility of the perovskite NCs. This work provides insight for expanding research activities on red-emitting perovskite NCs by developing a new strategy to improve the stability of the NCs, which is beneficial for both cost-effective bioimaging applications and heavy metal ion detection in water.

Performance evaluation of free hole-transport layer CsPbI3 perovskite solar cells

Stable inorganic cesium lead iodide (CsPbI3)-based perovskite solar cells received intensive research in the last 2 decades. Several experimental and simulation studies have been performed on CsPbI3 solar cells to achieve high efficiency. However, the usage of the hole-transport layer (HTL) has a good impact on the solar cell’s power conversion efficiency (PCE); HTL layer usage increases the cost of the cell. In this work, a SCAPS-1D simulation study is performed on HTL-free CsPbI3 perovskite solar cells to enhance the device performance. The optical refractive index and reflectivity of CsPbI3 are calculated with density functional theory. The solar cell device structure is investigated and optimized by changing parameters like metal back contact work function, absorber thickness, acceptor density, and defect density. It is found that the optimized solar cell device achieved a PCE of 17.2% with Selenium (Se) as a back metal contact. The optimized absorber thickness for the best PCE is 2000 nm, doping density concentration of 1 × 1019 cm−3, and defect density concentration of 2 × 1012 cm−3. A PCE of 24.5% is achieved using these parameters of the CsPbI3 absorber. The simulation study may guide the fabrication of low-cost and highly efficient HTL-free inorganic CsPbI3 solar cells.

Using Agricultural Mixed Waste as a Sustainable Technique for Removing Stable Isotopes and Radioisotopes from the Aquatic Environment

In the current study, dried ground mixed waste of olive waste and water hyacinth was subjected to the treatment of wastewater contaminated with stable or radioactive cobalt and cesium. Contact time, temperature, amount of adsorbent, metal ion concentration and pH-value were evaluated as the most potent factors that affect the adsorption process. Concentrations of Co and Cs ions before and after treatment are measured using ICP-OES technique. Moreover, kinetic and equilibrium isotherm parameters were investigated by explaining the equilibrium data by induction of two isotherms, “Langmuir” and “Freundlich”. Experimental results indicated that more than 85% of 60Co and 134Cs were efficiently removed from spiked wastewater after one hour of contact time by using 0.2 g of dried mixed waste. The optimal time to remove Cs+ and Co2+ was 50 and 90 min, respectively. The kinetic study showed that the adsorption of Cs+ and Co2+ were better suited to the second order. The most favorable pH value was at a range of 6–7 for Cs+ and 5–6 for Co2+. R2 values were higher at the Freundlich isotherm, indicating that the adsorption process was taking place according to Freundlich isotherm at all temperatures for Co2+ and Cs+ ions.

Stable and luminescent cesium copper halide nanocrystals embedded in flexible polymer fibers for fabrication of down-converting WLEDs.

Recently, CsPbX3 (X = I, Br, Cl) perovskite nanocrystals (NCs) have drawn wide attention owing to their outstanding photophysical and optoelectronic properties. However, the toxicity of such NCs remained a big challenge for further commercialization. Herein, we adopt facile methods for synthesizing green-emissive Cs3Cu2Cl5 and blue-emissive Cs3Cu2Br2.5I2.5 perovskite NCs that exhibit broad emission spectra with large Stokes shifts. These NCs showed photoluminescence quantum yields (PLQY) up to 65% (Cs3Cu2Cl5 NCs) and 32% (Cs3Cu2Br2.5I2.5 NCs) with limited stabilities. To further improve the stability, the NCs were blended with a hydrophobic polymer poly-methylmethacrylate (PMMA) and embedded inside the polymer fiber by an electrospinning process to form composite fibers. The as-prepared Cs3Cu2Cl5@PMMA and Cs3Cu2Br2.5I2.5@PMMA fiber films demonstrated good surface coverage and better thermal stability, and even retained their emission properties when dispersed in water. The emissive fibers were also deposited on flexible polyethylene terephthalate (PET) substrates that displayed high resistance towards bending and twisting with no signs of breakage, damage, or loss of optical properties. Finally, UV-pumped phosphor-converted WLEDs fabricated by using these blue and green-emitting fibers revealed CIE chromaticity coordinates at (0.27, 0.33) with a maximum luminous efficiency of 69 Lm W-1 and correlated color temperature (CCT) value of 8703 K. These outcomes can be beneficial for the development of futuristic flexible display technologies.

Investigation of Surface Ionization Detector for Cesium Oven Evaporation Rate

To assure stable cesium injection for negative ion source, the surface ionization detector (SID) is applied for diagnosis. Consisted of emitter and collector, the SID is operating based on bias voltage setting to drive the ionized cesium ions from emitter to the collector for detection. An analysis model of SID for cesium oven evaporation rate is established, investigating the process of cesium transportation in vacuum, thermionic ionization and cesium ion collection. Cesium transportation from nozzle to SID in vacuum is studied on the basis of free molecule flow model, and the cesium density distribution is obtained after having estimated cesium flux density ratio intercepted by SID from nozzle. The collection period is analyzed by particle tracking model, providing the relationship of SID current and ionized cesium current under adaptive bias voltage along with characteristics between SID current and bias voltage reproduced corresponding to experimental results. The model is adjustable and flexible to deal with different 3D structures, geometry and electric field setting. SID analysis for cesium oven of HUST negative ion source is carried out to monitor oven operation and to provide evaporation rate features under various oven temperatures along with error analysis.

Effect of Interface Modification on Mechanoluminescence-Inorganic Perovskite Impact Sensors.

It is becoming increasingly important to develop innovative self-powered, low-cost, and flexible sensors with the potential for structural health monitoring (SHM) applications. The mechanoluminescence (ML)-perovskite sensor is a potential candidate that combines the light-emitting principles of mechanoluminescence with the light-absorbing properties of perovskite materials. Continuous in-situ SHM with embedded sensors necessitates long-term stability. A highly stable cesium lead bromide photodetector with a carbon-based electrode and a zinc sulfide (ZnS): copper (Cu) ML layer was described in this article. The addition of a magnesium iodide (MgI2) interfacial modifier layer between the electron transport layer (ETL) and the Perovskite interface improved the sensor's performance. Devices with the modified structure outperformed devices without the addition of MgI2 in terms of response time and impact-sensing applications.

Investigation of photovoltaic performance of lead-free CsSnI3-based perovskite solar cell with different hole transport layers: First Principle Calculations and SCAPS-1D Analysis

Perovskite solar cells (PSCs) are getting maximum consideration among the research community because of the abrupt rise in their power conservation efficiency (PCE) to 25.5 % within a short span of time. However, the toxicity of the more dominating lead (Pb) based perovskites has been a major obstacle in the path of its commercialization. In this study, we have performed a systematic investigation of the photovoltaic (PV) properties of Pb- free PSCs, consisting of an excellent thermally stable Cesium Tin Iodide (CsSnI3) as an absorber layer. We have explored the impact of three common hole transport layers (HTLs) namely poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(3,4-ethylenedioxythiophene) (PEDOT: PSS) and (2,2′,7,7′-Tetrakis [N, N-di(4-methoxyphenyl) amino]-9,9′-spirobifluorene) (Spiro-OMeTAD) on the performance metrics of the PSCs. The impact of thickness variation, doping density, and defect density of the absorber layer on the PV parameters namely the short circuit current density (Jsc), open circuit voltage (Voc), PCE and Fill Factor (FF) is also examined. Our proposed device comprising of a planer p-n heterojunction structure with p-type CsSnI3 as absorber layer (FTO/n-TiO2/p-CsSnI3/p-HTL) is simulated using SCAPS-1D. WIEN2K software is used to calculate the electrical and optical characteristics of the absorber layer. We found that the P3HT-based device (FTO/n-TiO2/p-CsSnI3/p-P3HT) shows the highest PCE of 26.40 % with FF of 78.21 %, Voc of 0.972 V, and Jsc of 34.70 mA/cm2. The outcomes and interpretation of this paper show that the possibility of achieving a high PCE perovskite device can be attained utilizing safe, and non-toxic materials like CsSnI3.