The double perovskite materials A2SnCl6 (A= Sr, K) demonstrate significantly enhanced stability compared to Sn2+ based perovskites, as well as promising optoelectronic properties including direct bandgaps. A2SnCl6 adopts a vacancy-ordered double perovskite structure featuring isolated [SnCl6] octahedra, which contribute to a quantum confinement effect that enhances photoluminescence. The calculated structures exhibit a cubic phase with the Fm-3m space group, and their lattice parameters agree closely with reported values. All double perovskites exhibit mechanical stability. The band gaps of the perovskites vary depending on the A substitution from K to Sr. The total density and partial density of states provide insights into the variations in band gaps. The optical properties are determined through frequency-dependent dielectric functions, with optical absorption occurring in the visible range of 400-800 nm. Considering the stability, bandgap, and optical absorption properties, A2SnCl6 (A= Sr, K) emerges as a potential material for photovoltaic applications.
Using the density functional theory, a first-principle approach, the structural, electronic, and optical properties of the double perovskites A2BX6 (A= Cs; B=Sn; X=Cl, Br, and I) were calculated. Calculated parameters lattice constants and band gaps agree with experimental and theoretical observations. The band gap of the A2BX6 compounds is within the optimal range for single-junction photovoltaic applications. The ideal band gap, high dielectric constants, and optimum light absorption of these perovskites make them suitable for high performance single and multi-junction perovskite solar cells
Research from WHO shows in every 1.44 minutes a teenager is killed in road traffic crashes around the world. Our paper suggests the use of Deep Learning Algorithms in preventing such casualties through hardware and software implementation of the device in motor vehicles, also to overcome the potential limitation of Face Recognition to go that extra mile. In this paper we suggest using the integration of 4 models namely, Face Detection, Passive Liveness Detection (PLD), Face Recognition, Eye Detection. The Face Detection model consists of 2 versions which use Haar Cascades and Histogram of Oriented Gradients (HOG). PLD model is used for Presentation Attack Detection. The face recognition model is trained using the shape predictor 68 landmarks which are unique for each face. Using these landmarks, eye detection is also performed and the monitoring of sleepiness is carried out with the overall results of 98% accuracy with the face detection model, 94% accuracy with the face recognition model (limited to n=10 faces per model) with an Eye Aspect Ratio threshold of 0.3. Along with that, different current attack scenarios/ limitations of Facial Recognition that will be faced with these devices are described. Based on these scenarios, some of the preventive methods are elaborated to make the purpose of the device to its fullest performance.
Wide band gap semiconductors such as TiO2, ZnO, and SnO2 etc., have attracted considerable research interest for their possible applications in emerging areas like Spintronics, photovoltaic and photocatalytic devices . Most important feature of doping is to achieve the room temperature ferromagnetism without altering the host semiconducting nature. SnO2 is one of the wide band gap semiconductor with rutile structure widely used in solar cells, transparent electrodes, gas sensors, LED, touch sensitive screens and transistors . Theoretical study was carried out in Mn doped rutile SnO2 using recently implemented Tran and Blaha's modified Becke-Johnson exchange potential model (TB-mBJ). The routine density functional theory calculations based on local density approximation (LDA) and generalized gradient approximation (GGA) underestimated the band gap of strongly correlated systems whereas TBmBJ exchange potential model was found to predict band structures and properties accurately.
The electronic structure and ground state properties of SC16-ZnO, Zn7Mg1O8 and Zn7Al1O8 were studied using Wien2k code. The doping effect of magnesium and aluminium on band structure of Zinc Oxide reveals that the profiles are identical, however slightly shifted due to band broadening. Using super cell approach the electronic and optical properties are also studied for Zn7Al1O8 and Zn7Mg1O8. The calculated parameters like onset of critical point or threshold value, fundamental band gap and dielectric functions are reported for SC16-ZnO, Zn7Mg1O8 and Zn7Al1O8.
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