Search

In this study, a novel perovskite solar cell (PSC) architecture is presented that utilizes an HTL-free configuration with formamide tin iodide (FASnI3) as the active layer and fullerene (C60) as the electron transport layer (ETL), which represents a pioneering approach within the field. The elimination of hole transport layers (HTLs) reduces complexity and cost in PSC heterojunction structures, resulting in a simplified and more cost-effective PSC structure. In this context, an HTL-free tin HC(NH2)2SnI3-based PSC was simulated using the solar cell capacitance simulator (SCAPS) within a one-dimensional framework. Through this approach, the device performance of this novel HTL-free FASnI3-based PSC structure was engineered and evaluated. Key performance parameters, including the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), power conversion efficiency (PCE), I-V characteristics, and quantum efficiency (QE), were systematically assessed through the modulation of physical parameters across various layers of the device. A preliminary analysis indicated that the HTL-free configuration exhibited improved I-V characteristics, with a PCE increase of 1.93% over the HTL configuration due to improved electron and hole extraction characteristics, reduced current leakage at the back contact, and reduced trap-induced interfacial recombination. An additional boost to the device's key performance parameters has been achieved through the further optimization of several physical parameters, such as active layer thickness, bulk and interface defects, ETL thickness, carrier concentration, and back-contact materials. For instance, increasing the thickness of the active layer PSC up to 1500 nm revealed enhanced PV performance parameters; however, further increases in thickness have resulted in performance saturation due to an increased rate of hole–electron recombination. Moreover, a comprehensive correlation study has been conducted to determine the optimum thickness and donor doping level for the C60-ETL layer in the range of 10–200 nm and 1012–1019 cm−3, respectively. Optimum device performance was observed at an ETL-C60 ultra-thin thickness of 10 nm and a carrier concentration of 1019 cm−3. To maintain improved PCEs, bulk and interface defects must be less than 1016 cm−3 and 1015 cm−3, respectively. Additional device performance improvement was achieved with a back-contact work function of 5 eV. The optimized HTL-free FASnI3 structure demonstrated exceptional photovoltaic performance with a PCE of 19.63%, Voc of 0.87 V, Jsc of 27.86 mA/cm2, and FF of 81%. These findings highlight the potential for highly efficient photovoltaic (PV) technology solutions based on lead-free perovskite solar cell (PSC) structures that contribute to environmental remediation and cost-effectiveness. [ABSTRACT FROM AUTHOR]

This paper introduces a novel and cost-effective method for detecting adulterated diesel, specifically targeting contamination with kerosene, by leveraging machine learning and the refractive index values of mixed diesel samples. It proposes a laser-based sensor, employing COMSOL simulations for synthetic data generation to facilitate machine learning training. This innovative approach not only streamlines the detection process by eliminating the need for expensive equipment and specialized personnel but also enables on-site testing without extensive sample preparation. The sensor's design, utilizing light refraction and reflection principles, allows for the accurate measurement of diesel adulteration levels. Validation results showcase the machine learning models' high precision in predicting adulteration percentages, as evidenced by an R-squared value of 0.999 and a mean absolute error of 0.074. This research signifies a leap in sensor technology, offering a practical solution for rapid diesel adulteration detection, especially in developing countries, by minimizing reliance on advanced laboratory analyses. The sensor's design aligns with the requirements for low-cost IoT technology, presenting a versatile tool for various applications. [ABSTRACT FROM AUTHOR]

In this study, a hybrid organic–inorganic perovskite solar cell (PSC) based on methylammonium germanium triiodide (MAGeI3), which is composed of methylammonium ( C H 3 N H 3 +) cations and germanium triiodide ( G e I 3 − ) anions, has been numerically studied using SCAPS-1d codes. An extensive investigation of various electron transport layers (ETLs) and hole transport layers (HTLs) was conducted to identify the most optimal device configuration. The FTO/ZnOS/MAGeI3/PEDOT-WO3 structure performed the highest efficiency of all combinations tested, with an impressive optimized efficiency of 15.84%. This configuration exhibited a Voc of 1.38 V, Jsc of 13.79 mA/cm2, and FF of 82.58%. J-V characteristics and external quantum efficiency (EQE) measurements indicate that this device offers superior performance, as it has reduced current leakage, improved electron and hole extraction characteristics, and reduced trap-assisted interfacial recombination. Optimum device performance was achieved at active layer thickness of 560 nm. These findings may also serve as a basis for developing lightweight and ultra-thin solar cells, in addition to improving overall efficiency. Furthermore, a comprehensive correlation study was conducted to evaluate the optimum thickness and doping level for both ZnOS-ETL and PEDOT-WO3-HTL. The photovoltaic performance parameters of the FTO/ZnOS/MAGeI3/PEDOT-WO3 structure were analyzed over a wide temperature range (275 K to 450 K). The structure exhibited stable performance at elevated operating temperatures up to 385 K, with only minimal degradation in PCE of approximately 0.42%. Our study underscores the promise of utilizing cost-effective and long-term stability materials like ZnOS and PEDOT-WO3 alongside the toxic-free MAGeI3 perovskite. This combination exhibits significant potential for eco-friendly PSC, paving the way for the development of highly efficient ultra-thin PSC. [ABSTRACT FROM AUTHOR]

Efficient drug delivery to target tissue is a major challenge in many cancer treatment modalities. Silica nanoparticles (SiNPs) have been identified as an ideal drug carrier due to their unique properties. In Photodynamic therapy (PDT), one of the key challenges in utilizing photosensitizers (PS) lies in effectively delivering the PS to the targeted tissue. Using Silica nanoparticles encapsulation will effectively prevent the leakage of entrapped PS from the particles, protects against reduction by the retinal endothelial system, and reduces PS toxicity. In this study, Silica nanoparticles (SiNPs) were used as carriers for Safranin (SF) as a photosensitizer agent to treat MCF-7 breast cancer cells in vitro. The SiNPs nanoparticles were synthesized, and their size and shape were measured using Transmission Electron Microscopy (TEM). Cytotoxicity was evaluated for different concentrations of encapsulated and naked SF. The optimal concentrations and exposure times required to eliminate the MCF-7 under light (Intensity ~110 mW/cm2, red laser) were determined. The results indicated that encapsulated SF by SiNPs exhibited higher efficacy than naked SF with a +50% concentration efficacy and +78% exposure time efficacy. This confirmed the superior ability of encapsulated SF to eliminate MCF-7 cells compared to naked SF. The use of synthesized silica nanoparticles loaded with SF improved photodynamic therapy by increasing the bioavailability of SF in the target cells. Our results demonstrate that SiNP encapsulation significantly improves the efficacy of SF in eliminating MCF-7 cells compared to bare SF. This study underscores the potential of SiNPs as a drug delivery system for photodynamic therapy and could pave the way for developing more effective cancer treatments. [ABSTRACT FROM AUTHOR]

This paper discusses the impact of the p-MoS2 transition metal dichalcogenide as an interfacial layer between the CZTS absorber and Mo back contact in the CZTS based solar cell. The study was performed using SCAPS-1D numerical simulation. The I–V characteristic demonstrated a higher slope than CZTS solar cells without considering the interfacial layer. The results verified that the p-MoS2 layer beneficially on the CZTS/Mo hetero-contact mediating an ohmic contact. Accordingly, the conversion efficiency improves from 12.14% to 16.71%. To evaluate the role of the p-MoS2 layer, various performance parameters such as open-circuit voltage (Voc), short circuit current (Jsc), fill factor FF, and efficiency η were explored versus thicknesses, bandgap energies, and the acceptor carrier concentration (NA). The results show that a thickness of the interfacial layer of less than 200 nm could cause deterioration of the overall cell performance, mainly due to created high barriers at the CZTS/p-MoS2 and p-MoS2/Mo interfaces, at low thicknesses, which impedes the drift of photogenerated holes. Additionally, increasing the NA above 1016 cm−3 improves the cell performance, owing to the favourable band alignment at the back contact. Values obtained for Voc and Jsc are 0.88 V and 25.5 mA/cm2, respectively. Moreover, the effect of series resistance Rs on CZTS solar cells was investigated. The efficiency decreases from 12.84% to 9.69% when the Rs correspondingly increases from 0 Ω to 5 Ω. [ABSTRACT FROM AUTHOR]

The influence of Molybdenum diselenide transition metal dichalcogenide material (p-type MoSe2 TMDC) as an interfacial layer between the ultra-thin Cu (In, Ga)Se2 (CIGS) absorber layer, with thickness less than 500 nm, and molybdenum back contact was studied using SCAPS-1D simulation package. The possible effects of the p-MoSe2 layer on the electrical properties and the photovoltaic parameters of the CIGS thin-film solar cells have been investigated. Band gap energy, carrier concentration, and the layer thickness of the p-MoSe2 were varied in this study. The optimum band gap is found to be of 1.3 eV. Interfacial layers of thicknesses less than 200 nm have been found to cause deterioration for the overall cell performance. This might be attributed to the increase in the back-contact recombination current and the reduction of the built-in potential at p-MoSe2/CIGS junction. Furthermore, the MoSe2 layer would form the so-called back surface field (BSF), due to the associated wider band gap with respect to that of CIGS absorber layer. Additionally, the simulation of the I–V characteristic showed a higher slope which implies that MoSe2 layer at the CIGS/Mo interface acts in a beneficial way on the CIGS/Mo hetero-contact adapting it from Schottky type contact to quasi-ohmic contact. The conversion efficiency has increased significantly from 14.61% to 22.08%, without and with the MoSe2 layer, respectively. These findings are very promising for future high performance and cost-effective solar cell devices. [ABSTRACT FROM AUTHOR]

The impact of molybdenum ditelluride (p-type MoTe2) transition metal dichalcogenide (TMDC) material formation as an interfacial layer between CdTe absorber layer and Mo back contact is investigated. The simulation is conducted using the solar cell capacitance simulator (SCAPS) software. Band gap energy, carrier concentration, and layer thickness of the p-MoTe2 have been varied in this study to investigate the possible influences of p-MoTe2 on the electrical properties and the photovoltaic parameters of CdTe thin film solar cells. It has been observed that a thickness of the p-MoTe2 interfacial layer less than 60 nm leads to a decrease in the cell performance. In regard to the effect of the band gap, a maximum efficiency of 16.4% at the optimum energy gap value of 0.95 eV has been obtained at a doping of 1 0 1 9 cm − 3 . Additionally, increasing the acceptor carrier concentration ( N A ) of MoTe2 enhances the solar cell performance. The solar cell efficiency reaches 15.5% with N A of 1 0 1 8 cm − 3 with layer thicknesses above 80 nm. This might be attributed to the possibility of forming a back surface field for the photogenerated electrons, which reduces recombination at the back contact and hence provides a low resistivity contact for holes. The results justify that the MoTe2 interfacial layer mediates an ohmic contact to CdTe films. [ABSTRACT FROM AUTHOR]

Abstract: We report the optimization of electron beam lithography and inductively coupled plasma (ICP) dry etching processes to fabricate pre-patterned Si (100) substrates with sub-100nm holes with controlled size and shape. An efficient in situ cleaning sequence based on atomic hydrogen cleaning at 500°C combined with thermal oxide desorption at 750°C confirmed by reflection high energy electron diffraction (RHEED) pattern of two dimensional clean surface prior to the MBE growth has been established. The MBE growth of GaAs/In0.15Ga0.85As/GaAs system on patterned Si surface has shown highly selective formation of localized dome like nanostructures in patterned holes with 1μm period. [Copyright &y& Elsevier]