Emitter Concentration Research Articles

Measurement of Alpha Emitters Concentration in Tomato Fruits Using CR – 39 Plastic Track Detector

Our country suffered from pollution translation as a result to the wars events, so, it is necessary to measure the amount of radiation in the fields that are of indirect contact with human life and health. The main aim of the present work is to measure the concentration of alpha emitters in tomato fruits collected from different farms in Al – Basra governorate in the south of Iraq. Nuclear track detectors of type CR – 39 are used as a detection device and Can technique as a detection technique. Results show that the maximum concentration recorded is sample no.7 of site Al – Rafidhya which was equal to (6.9621 ± 0.111) ppm and sample no.1 of site Lothan with concentration equals to (4.9236 ± 0.117) ppm. The minimum concentrations were in sample 6 of site Al – Lehaiss (1.5360 ± 0.084) ppm followed by sample 9 of site Malhan which recorded (1.6840 ± 0.111) ppm (20.208 ± 1.332 Bq/m3).

Modeling and simulation of a high power InGaP/GaAs heterojunction alphavoltaic battery irradiated by americium-241

The design of semiconductor-based heterojunction structures can be turned useful to raise the efficiency of nuclear micro-batteries. In this study, we have investigated a micro-power alphavoltaic battery by using a lab-made software. The nuclear battery consists of an In0.49Ga0.51P/GaAs heterostructure irradiated by americium-241 (Am241) alpha particles with an average kinetic energy of 5.485 MeV. The alphavoltaic battery exhibits an overall active area of 1 cm2. Based on a comprehensive analytical model, the device current density-voltage J(V) and output electric power P(V) characteristics are simulated extracting the energy conversion efficiency. The model takes into account the reflection of the incident alpha particles, the ohmic losses, the effect of the boundary between the two layers, and the depletion region borders. Different values of the radioisotope apparent activity density, the emitter and base dopant concentrations, and the surface recombination velocities in both the front and back layers are considered during the simulations to optimize the battery performance. The present study reports that by irradiating by a 2.4 mCi/cm2 Am241 source, the obtained energy conversion efficiency of the battery can reach 10.31% with a maximum output power density of 16.07 µW/cm2. Therefore, In0.49Ga0.51P/GaAs heterostructure coupled with Am241 seems a promising design for long-term energy supply in harsh environments.

AFORS-HET-based numerical exploration of tunnel oxide passivated contact solar cells incorporating n- and p-type silicon substrates.

The development of a tunnel oxide interfacial layer capped by a highly doped poly-Si layer is considered one of the most promising methods to reduce charge carrier recombination and improve the performance of conventional PERC devices. The thickness and doping concentration of emitters and BSF layers greatly influence the tunnelling current in TOPCon devices. In this research, we evaluated the performance of tunnel oxide passivated contact (TOPCon) solar cells by conducting an in-depth analysis of various key parameters. The parameter include the type of silicon substrate (n or p-type); the thickness and doping density (N a/N d) of n, n+, p, and p+ layers; and surface recombination velocity (front/rear), which were analyzed using AFORS-HET simulation software. A comparative analysis of performance demonstrates that the highest efficiency is achieved in the n-TOPCon solar cell with the following values: V oc = 660.2 mV, J sc = 45.05 mA cm-2, FF = 82.87%, and PCE = 25.74%. In the optimized p-TOPCon solar cell, the open circuit voltage (V oc) and fill factor (FF) exhibit improvements of 35.9 mV and 0.39%, respectively. However, the values of J sc and PCE decrease by 6.44 mA cm-2 and 2.2%, respectively, in p-TOPCon solar cells. Furthermore, photo-electroluminescence analysis reveals that the n-TOPCon solar cells exhibit a higher maximum photon flux (front/rear) than p-TOPCon solar cells.

Measurements of alpha emitter concentrations (222Rn, 226Ra, and 238U )in blood samples of patients with renal failure of non-smokers in Najaf City, Iraq

Measurements of alpha emitter concentrations (222Rn, 226Ra, and 238U )in blood samples of patients with renal failure of non-smokers in Najaf City, Iraq

Effect of Structural Parameters on Current-Voltage Properties of GaAs-based Resonant Tunneling Diodes Using Device Simulator

The resonant tunneling diode (RTD) was first introduced by Tsu and Esaki back in 1973. The RTD has a nano-meter scale dimension and is capable to operate in the terahertz range of frequency, thanks to its unique negative differential resistive (NDR) property. There are tons of potential of RTD capable to implement in many applications if the optimum scales and parameters of the RTD’s structure can be determined. Hence, this is the reason and purpose of this work being conducted. The effects of structural parameters of RTD are studied and analyzed. From the simulation results generated by the WinGreen simulator, the barrier layer thickness has exhibited to be the most performance-affective structural parameter for RTD, when compared to other parameters such as thicknesses of spacer and quantum-well layers, and doping concentration of emitter and collector layers. The highest peak-to-valley current ratio (PVCR) of InGaAs/AlAs RTD achieved is approximately 78.36 with its barrier layer thickness of 1.6 nm. For GaAs/AlAs RTD, the highest PVCR obtained is approximately 59.29 at 1.6 nm thick of its barrier layer.

Naptha-phenanthroimidazole-based blue fluorophores (y

Organic light-emitting diodes are a promising new technology for next-generation displays and lighting applications, particularly in the quest for efficient deep blue fluorophores (y= < 0.05). Despite the receipt of several reports, it remains imperative to advance the development of a deep blue emitter that can address solubility, stability, color purity, and efficiency. Eye on these challenges, herein, four new blue phenanthroimidazole and naphthalene-based derivatives, 2-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazole(Pq-NH-NA), 2-(naphthalen-1-yl)-1-phenyl-1H phenanthro [9,10-d]imidazole (Pq-An-NA), 2-(naphthalen-1-yl)-1-(3-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazole (Pq-mF-NA), and 2-(naphthalen-1-yl)-1-(4-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazole (Pq-pF-NA) were designed and synthesized. Further, the PI molecules were structurally characterized by spectroscopic analysis, and their thermal decomposition (Td) is found to be 203–309 °C. Substitution at the N1 position of imidazole provides a facile alternative role for photophysical and electronic properties. The PI fluorophores were further characterized in solution, thin-film, and solid where the solid results are enhanced in terms of intense color emission (x = 0.158, y = 0.037). It showed a good quantum yield of 14.28 % in solution and 19.33 % in solid, indicating that fluorinated molecules lead to better performance than the rest of them. Additionally, the InGaN LED fabricated with the fluorinated molecule Pq-pF-NA emitted 425 nm with a deep blue emission and yielding CIE color coordinates (x = 0.154, y = 0.048). The film study also revealed the deep blue emission with increasing concentration of emitter (2.5 %). The observed results apprise that the synthesized fluorophores are efficient to deep blue emitters and capable candidates for organic light-emitting diodes.

In silico studies of OLED device architectures regarding their efficiency

Simulations have become increasingly important to understand and design organic optoelectronic devices, such as organic light emitting diodes (OLEDs) and to optimize their performance by selecting appropriate materials and layer arrangements. To achieve accurate device simulations, it is crucial to consider the interplay between material properties, device architecture, and operating conditions and to incorporate physical processes such as charge injection, transport, recombination, and exciton decay. Simulations can provide insights into device bottlenecks and streamline optimization cycles, eliminating the need for physical prototyping and rationalizing OLED design. In this study, we investigated three heuristic OLED architectures with a 3D kinetic Monte Carlo (kMC) model and compared their quantum efficiency at different operation voltages. Our investigation focused on examining the effects of various layer arrangements on charge and exciton dynamics in OLED devices and establishing design principles for achieving high efficiency, which are consistent with experimental observations. Notably, we find that increasing the thickness of the emissive layer (EML) led to higher luminance efficiency, and that an emitter concentration of approximately 5% results in optimal performance. By using this model, it is possible to rapidly study the influence of many device parameters and explore a broad range of parameter and architecture space within a reasonable time-frame.

Swinging between shine and shadow: Theoretical advances on thermally activated vibropolaritonic chemistry.

Polariton chemistry has emerged as an appealing branch of synthetic chemistry that promises mode selectivity and a cleaner approach to kinetic control. Of particular interest are the numerous experiments in which reactivity has been modified by virtue of performing the reaction inside infrared optical microcavities in the absence of optical pumping; this effort is known as "vibropolaritonic chemistry." The optimal conditions for these observations are (1) resonance between cavity and reactive modes at normal incidence (k = 0) and (2) a monotonic increase of the effect with the concentration of emitters in the sample. Importantly, vibropolaritonic chemistry has only been experimentally demonstrated in the so-called "collective" strong coupling regime, where there is a macroscopic number of molecules (rather than a single molecule) coupled to each photon mode of the microcavity. Strikingly, efforts to understand this phenomenon from a conceptual standpoint have encountered several roadblocks, and no single, unifying theory has surfaced thus far. This Perspective documents the most relevant approaches taken by theorists, laying out the contributions and unresolved challenges from each work. We expect this Perspective to not only serve as a primer for experimentalists and theorists alike but also inform future endeavors in the quest for the ultimate formalism of vibropolaritonic chemical kinetics.

Toward highly efficient deep-blue OLEDs: Tailoring the multiresonance-induced TADF molecules for suppressed excimer formation and near-unity horizontal dipole ratio.

Boron-based compounds exhibiting a multiresonance thermally activated delayed fluorescence are regarded promising as a narrowband blue emitter desired for efficient displays with wide color gamut. However, their planar nature makes them prone to concentration-induced excimer formation that broadens the emission spectrum, making it hard to increase the emitter concentration without raising CIE y coordinate. To overcome this bottleneck, we here propose o-Tol-ν-DABNA-Me, wherein sterically hindered peripheral phenyl groups are introduced to reduce intermolecular interactions, leading to excimer formation and thus making the pure narrowband emission character far less sensitive to concentration. With this approach, we demonstrate deep-blue OLEDs with y of 0.12 and full width at half maximum of 18 nm, with maximum external quantum efficiency (EQE) of ca. 33%. Adopting a hyperfluorescent architecture, the OLED performance is further enhanced to EQE of 35.4%, with mitigated efficiency roll-off, illustrating the immense potential of the proposed method for energy-efficient deep-blue OLEDs.

Stable electrospray signal on a microfabricated glass chip with three-dimensional open edge and tiered depth geometries

This paper presents the microfabrication and performance of a three-dimensional electrospray ionization (ESI) emitter tip made from glass, which achieves stable current signals important for chemical analysis. Our novel microfabrication process and custom-built signal conditioning hardware provides the advantage of providing accurate features and steady signals. The fabrication process relies on standard microfabrication techniques (i.e., deposition, photolithography, and wet etching). This fabrication method involves the novel application of two layers of positive and negative photoresists in addition to Parafilm® wax tape. Open edge and tiered depth details were successfully created from a multilayer planar mask. This is a benefit for integrated miniaturized and microfluidic systems that often require micro features for their functionality but relatively large millimeter size features for their physical periphery. We demonstrate the fundamental performance of electrospray with this microfluidic chip. The emitter tip was fixed on a linear axis stage with high resolution (10 μm) to finely control the tip distance from a metal counter electrode plate. A custom printed circuit board system was built to safely control four voltages applied to the microchip ports from a single high voltage power supply. To readily form the electrospray, non-aqueous solvents were used for their low viscosity and a constant voltage of +2.7 kV was applied to the sheath electrospray microchannel. The liquid being sprayed was 80/20 (v/v) methanol/acetonitrile with 0.1% acetic acid in the sheath microchannel and with ammonium acetate (10–40 mM) in its remaining microchannels. The electrospray signal was measured in response to varying the distance (1.4 to 1.6 mm) between the electrospray emitter tip and a metal counter electrode plate in addition to the varying concentration of the background electrolyte, ammonium acetate. Stable and repeatable electrospray signal showed linear relationships with emitter tip distance and concentration (r2 ≥ 0.95).

Optimization of N-PERT Solar Cell under Atacama Desert Solar Spectrum.

In the Atacama Desert, the spectral distribution of solar radiation differs from the global standard, showing very high levels of irradiation with a particularly high ultraviolet content. Additionally, the response of photovoltaic (PV) technologies is spectrally dependent, so it is necessary to consider local conditions and type of technology to optimize PV devices since solar cells are usually designed for maximum performance under standard testing conditions (STC). In this work, we determined geometrical and doping parameters to optimize the power of an n-type bifacial passivated emitter and rear totally diffused solar cell (n-PERT). Six parameters (the thicknesses of cell, emitter, and back surface field, as well as doping concentration of emitter, base, and back surface field) were used to optimize the cell under the Atacama Desert spectrum (AM 1.08) and under standard conditions (AM 1.5) through a genetic algorithm. To validate the model, the calculated performance of the n-PERT cell was compared with experimental measurements. Computed and experimental efficiencies showed a relative difference below 1% under STC conditions. Through the optimization process, we found that different geometry and doping concentrations are necessary for cells to be used in the Atacama Desert. Reducing the thickness of all layers and increasing doping can lead to a relative increment of 5.4% in the cell efficiency under AM 1.08. Finally, we show the potential effect of metallization and the viability of reducing the thicknesses of the emitter and the back surface field.

Benzimidazole-substituted bisanthracene: a highly efficient deep-blue triplet–triplet fusion OLED emitter at low dopant concentration

Two anthracene derivatives, MAnBz and DiAnBz, have been developed as emitters for deep-blue triplet–triplet fusion (TTF) fluorescence organic light emitting diodes (OLEDs). DiAnBz bearing two anthracene units at a closed distance, separated by one phenylene moiety, shows high photoluminescent quantum yields and deep-blue emission. The remarkable maximum external quantum efficiency (EQEmax) of 6.7% and 8.3% are obtained from DiAnBz-OLEDs with pristine prompt fluorescence and TTF fluorescence models, respectively. In particular, effectively diffusive TTF characteristics still can be detected at DiAnBz-OLED with an extreme low emitter concentration of 1 wt%, whose device performance exhibited a high EQEmax of 7.0% with deep blue emission at CIE (0.148, 0.078). The diffusive TTF characteristics with 20 times shorter delayed emission lifetime (τ2 of 3–4 μs), in comparison with that of MAnBz (τ2 of 60–70 μs) in the time-resolved electroluminescence experiments. This implies that pairing and TTF of the DiAnBz triplet excitons are more effective than that of MAnBz in the light emitting layer.

Visualizing Bioabsorbable Spacer Effectiveness by Confirming the Distal-Tail of Carbon-Ion Beams: First-In-Human Report.

In particle therapy, bioabsorbable polyglycolic acid (PGA) spacer was developed to reduce the healthy organ irradiation dose, especially in the gastrointestinal tract. The PGA spacer is safe and effective; however, there are no reports that have confirmed whether the PGA spacer which inserted in the body actually stops the carbon-ion (C-ion) beams. Here, we visualized and confirmed that the PGA spacer stops the C-ion beams in the body based on the dose distribution using auto-activation positron emission tomography (AAPET). A 59-year-old dedifferentiated retroperitoneal liposarcoma patient underwent C-ion radiotherapy (C-ion RT) on referral. A month before C-ion RT initiation, the patient underwent PGA spacer placement. Postoperatively, the patient received 4.4 Gy (RBE) per fraction of C-ion RT, followed by AAPET. AAPET revealed lower positron emitter concentrations at the distal tissue ventral to the PGA spacer than in the planning target volume. In observing the efficacy of the PGA spacer, the AAPET images and the average count per second of the positron emitter suggested that the PGA spacer stopped the C-ion beams in the body in accordance with the dose distribution. Therefore, AAPET was useful in confirming the PGA spacer’s effectiveness in this study, and the PGA spacer stopped the C-ion beams.

P‐127: Student Poster: Highly Efficient Green Hyper‐fluorescent Organic Light‐Emitting Diodes using tetradentate Pt(II) Complex as Phosphorescent Sensitizer

We developed green hyper‐fluorescent organic light‐emitting diodes (OLEDs) using tetradentate Pt(II) complex phosphorescent sensitizer to improve external quantum efficiency (EQE) and reduce efficiency roll‐off through suppressed Deter energy transfer to green fluorescent emitter of N9,N9,N10,N10‐tetrakis(4‐(2‐phenylpropan‐2‐yl)phenyl)anthracene‐9,10‐diamine (PhtBuPAD). The tetradentate Pt(II) complex including bulky blocking unit prevented Dexter energy transferred into green fluorescent emitter. In the device evaluation, the hyper‐fluorescent OLED is maintained the high EQE of 21.1% in spite of a high doping concentration of green fluorescent emitter of 3 wt%. As a result, the maximum EQE at optimized doping concentration 2 wt% shows 23.4% and 22.2% at 3000 cd/m2. It induced only 5.0% efficiency roll‐off, which is 6.4‐fold improvement compared to our previous work.

Industrial emissions effect into atmospheric air quality: mathematical modeling.

This paper presents the results of modeling the distribution process of industrial emission components at specified distances from the emission source along the normal. The model uses a system of differential diffusion equations to compute the concentration profiles of aerosols, industrial gases, and fine particles in the atmosphere. In order to investigate the regularity of the emitter propagation into the atmosphere, a theory of impurity dispersion was developed. The model is constrained by the effect of particle interactions. The partial derivative equations are presented to calculate the concentrations of aerosols and fine particles under the turbulent airflow in the atmosphere, dispersion of inert impurities, and distribution of chemically active compounds. The adequacy of the mathematical model for a series of theoretical calculations was checked by contrasting the data of the atmospheric air monitoring for the cities of Almaty, Ust-Kamenogorsk, Pavlodar, Atyrau, Krasnodar, Chelyabinsk, Beijing, and Shanghai. Air monitoring data included PM10, SO2, and NO2 levels. The mathematical model solutions for the relative values of the emitter concentration in the direction along the normal of the pollution source at the surface were obtained. Graphical interpretation of the calculation results over the 0…200m distance for time intervals ranging from 3 to 600min was provided. According to the multiple factor cluster analysis, the critical values of SO2 concentrations in Atyrau exceeded MPC in 26.2% of cases. The level of NO2 for Shanghai was 15.6%, and those for PM10 concentrations in Almaty and Atyrau amounted to 16.4%. A comparison of theoretical values and results obtained from official sources showed arithmetic mean of 49.4mg/m3 and maximum value of 823.0mg/m3. Standard deviation comprised 48.9mg/m3. Results were considered statistically significant at p≤0.005. The mathematical model developed in this study can be used to predict the status of atmospheric air.

Assessment of DNA Damage in Blood of Iraqi Museum Workers

: This study was done to evaluate the risk of natural alpha emitter's concentrations in blood of museum employees and any potential DNA damage that may be linked to it. The current research was conducted on employees in State board of antiquities and heritage, Abd alkarim qasim museum and Iraqi museum. Blood samples were collected from 30 participants in employees group and 30 participants in controls group that was collected from general population. Alkaline comet assay has been used to assess DNA damage in lymphocytes of participants. The results showed higher DNA damage and in employees compared with control group high comet L/W value (1.56) (1.1).Thesmokers have increased average L/W value compared to participants who never smoked in employee group. From this study concluded based on these results, exposure of museum employees and archaeologists to natural ionizing radiation may have increased risk to DNA damage and cancer compared to non-occupational employees.

Simple Double Hetero[5]helicenes Realize Highly Efficient and Narrowband Circularly Polarized Organic Light-Emitting Diodes

Simple Double Hetero[5]helicenes Realize Highly Efficient and Narrowband Circularly Polarized Organic Light-Emitting Diodes

Luminescent Lifetime Regulation of Lanthanide-Doped Nanoparticles for Biosensing.

Lanthanide-doped nanoparticles possess numerous advantages including tunable luminescence emission, narrow peak width and excellent optical and thermal stability, especially concerning the long lifetime from microseconds to milliseconds. Differing from other shorter-lifetime fluorescent nanomaterials, the long lifetime of lanthanide-doped nanomaterials is independent with background fluorescence interference and biological tissue depth. This review presents the recent advances in approaches to regulating the lifetime and applications of bioimaging and biodetection. We begin with the introduction of the strategies for regulating the lifetime by modulating the core–shell structure, adjusting the concentration of sensitizer and emitter, changing energy transfer channel, establishing a fluorescence resonance energy transfer pathway and changing temperature. We then summarize the applications of these nanoparticles in biosensing, including ion and molecule detecting, DNA and protease detection, cell labeling, organ imaging and thermal and pH sensing. Finally, the prospects and challenges of the lanthanide lifetime regulation for fundamental research and practical applications are also discussed.

Boost in Solid‐State Photon Upconversion Efficiency through Combined Approach of Melt‐Processing and Purification

Realization of efficient photon upconversion (UC) mediated by triplet–triplet annihilation (TTA) in a solid state is a great challenge, even though order of magnitude higher efficiencies are routinely reported in a solution/liquid state. To address this issue in a typical emitter/sensitizer UC system, a combined approach is introduced based on 1) thorough emitter purification for reduced exciton quenching and 2) UC film fabrication via melt‐processing for attaining large emitter concentrations with suppressed aggregation. Emitter purification via vacuum sublimation is shown to reduce the number of both singlet and triplet quenchers as confirmed by fluorescence and UC quantum yield measurements along with the respective transient measurements performed on nanosecond and millisecond time domains. Application of this approach to the benchmark TTA‐UC system DPA/PtOEP is demonstrated to yield a record‐high UC efficiency (=8 ± 1%, out of maximum 50%) achieved at 40 wt% of DPA homogeneously dispersed in the PMMA host. Importantly, such high efficiency is accomplished in large‐area amorphous films, the most preferred for practical applications, and featuring low UC threshold (=5 mW cm−2) that is close to the solar irradiance. The presented approach describes the guidelines for boosting UC efficiency in the solid state, and generally, is applicable to any conventional TTA‐UC system.

Optimization of Effective Doping Concentration of Emitter for Ideal c-Si Solar Cell Device with PC1D Simulation

Increasing silicon solar cell efficiency plays a vital role in improving the dominant market share of photo-voltaic systems in the renewable energy sector. The performance of the solar cells can be evaluated by making a profound analysis on various effective parameters, such as the sheet resistance, doping concentration, thickness of the solar cell, arbitrary dopant profile, etc., using software simulation tools, such as PC1D. In this paper, we present the observations obtained from the evaluation carried out on the impact of sheet resistance on the solar cell’s parameters using PC1D software. After which, the EDNA2 simulation tool was used to analyse the emitter saturation current density for the chosen arbitrary dopant profile. Results indicated that the diffusion profile with low surface concentration and shallow junction depth can improve the blue response at the frontal side of the solar cell. The emitter saturation current density decreases from 66.52 to 36.82 fA/cm2 for the subsequent increase in sheet resistance. The blue response also increased from 89.6% to 97.5% with rise in sheet resistance. In addition, the short circuit density and open circuit voltage was also observed to be improved by 0.6 mA/cm2 and 3 mV for the sheet resistance value of 130 Ω/sq, which resulted in achieving the highest efficiency of 20.6%.