Journal of Optoelectronical Nanostructures
Volume:7 Issue: 4, Autumn 2022

As fossil fuels cause environmental problems and begin to become depleted, research into developing renewable energy is on the rise. As fossil fuels begin to deplete and the cost of energy rises, there is more and more need for a renewable, clean energy source. One such possible alternative are OSC . Experimental results have reported 8.3% efficiency in lab tests. The development of OSC efficiency is an important step in reducing our carbon footprint. The absorption of photons is not a problem in most OSC because normally 96% of light is absorbed and organic semiconductors have high absorption coefficients even for very thin specimen. After the photons are absorbed, an exciton consisting of a hole and an electron with a binding energy of 0.1 - 1.4 eV is formed. In this article, three different models for the bimolecular recombination of solar cells are explored and a simulation is run and compared to experimental results.

In this study, an experimental investigation on the synthesis method of a ferro-fluid was conducted in order to obtain a highly stable ferro-fluid. For this purpose, various surfactants are applied for colloidal stabilization among which tetra methyl ammonium hydroxide (TMAOH) showed the best performance. Several methods of characterization were chosen to characterize synthesized ferro-fluids such as Zeta potential and the particle size analysis by Dynamic Light Scattering (DLS). Based on the DLS results, the average diameter of Fe3O4 nano-particles was about 30 nm. Besides, the Zeta potential analysis was applied to investigate the stability of synthesized ferro-fluids. Moreover, the dynamic viscosity of the ferro-fluid is estimated at four different temperatures (20 oC, 35 oC, 50 oC, 65 oC). Based on the results, the ferro-fluid viscosity is decreased significantly by the temperature increase. Further, it is obvious that the viscosity of the ferro-fluid is decreased exponentially in terms of shear rate which determines its shear thinning (non-Newtonian) behavior.

The relatively large bandgaps of the methylammonium lead halide perovskites are the major obstacle to achieving broadband response in the lead-based perovskite photodetectors. Partial or total substitution of lead with tin leads to smaller bandgaps for perovskite materials. Here, we investigated the application of a mixed tin-lead perovskite material, (FASnI3)0.6(MAPbI3)0.4, with small bandgap of 1.24 eV as the absorber material in a perovskite photodetector. The device simulation is performed by using SCAPS simulation software. The effect of different parameters such as absorber layer quality and thickness, interface defects, doping concentration and carrier mobility on the performance of the device is studied. The simulation results clarify that the parameters optimization can result in achieving a self-powered photodetector with broad spectral response from 300 to 1050 nm wavelength, a high responsivity of 0.6 A W-1 at 930 nm, almost flat detectivity of over 1013 Jones and a wide linear dynamic range. We believe this study can provide theoretical guidance for the design of highly sensitive, broadband, mixed tin-lead perovskite photodetectors.

The binding energy of a tuned quantum dot (QD) under an external magnetic field have been theoretically investigated. For this goal, the Schrödinger equation is analytically solved without and with considering the impurity term and the energy eigenvalues and eigenfunctions are analytically derived. Then, the binding of the tuned QD was studied considering the various parameters. We found that (i) the binding energy decrease with rising the potential range. (ii) The binding energy reduces with enhancing the potential depth. The depth and stretching range of the confinement potential have important effects on the binding energy of the tuned QD.The binding energy of a tuned quantum dot (QD) under an external magnetic field have been theoretically investigated. For this goal, the Schrödinger equation is analytically solved without and with considering the impurity term and the energy eigenvalues and eigenfunctions are analytically derived. Then, the binding of the tuned QD was studied considering the various parameters. We found that (i) the binding energy decrease with rising the potential range. (ii) The binding energy reduces with enhancing the potential depth. The depth and stretching range of the confinement potential have important effects on the binding energy of the tuned QD.

In this paper an optical filter based on 2D hexagonal photonic crystals that is suitable for the third window of optical communications is proposed. The structure consists of two waveguides including one L4 resonant cavity created by removing 4 holes between them, and one L1 resonant cavity by removing 1 hole near the output waveguide; moreover, 8 holes around the L4 cavity had been selected for optofluidic infiltration within them. This structure is very flexible, and different wavelengths in the third telecommunication window can be chosen using selective optofluidic infiltration with different refractive indices. Simplicity in design, no need to change the size of the holes and separating the desired wavelengths by selecting different optofluidic infiltration materials are the main features of this study. The plane-wave expansion method (PWE) and the finite-difference time-domain method (FDTD) have been used to extract the photonic bandgap and study the behavior of the photonic structure, respectively.

The electrochemical behavior of captopril at the surface of a carbon-paste electrode (CPE) modified with gold nanoparticles (GNPs) is described. The prepared electrode shows an excellent electrocatalytic activity toward the oxidation of captopril, which is leading to marked considerable improvement of sensitivity. Whereas at the surface of unmodified electrode an electrochemical activity for captopril cannot be observed, a very sharp anodic wave with an anodic peak potential about 1.0V (versus Ag/AgCl) is obtained using the prepared modified electrode. Captopril oxidation on CPE/GNPs proceeds at pH between 4.0 and 10.0. Under the optimized conditions, the electrocatalytic oxidation peak current of captopril showed two linear dynamic ranges with a detection limit of 8.28×10-2 µM captopril. The linear calibration range was 1.14-16.98 and 21.49-62.1 µM using amperometric. Finally, the sensor was examined as a selective, simple, and precise new electrochemical sensor for the determination of captopril in pharmaceutical samples including tablets and satisfactory results were obtained.