PREDICTIVE MODELING OF MIXED HALIDE PEROVSKITE CELL USING HYBRID L27 OA TAGUCHI-BASED GA-MLR-GA APPROACH

Perovskite photovoltaic cell is regarded as an alternative configuration for the conventional photovoltaic cells predominantly due to its high efficiency. In this paper, a predictive modeling using a hybrid L27 orthogonal array (OA) Taguchi-based Grey relational analysis (GRA), multiple linear regression (MLR) and genetic algorithm (GA) was proposed to optimize the device parameters for better overall performance. The Perovskite photovoltaic cell model is initially constructed and simulated using solar cell capacitance simulator (SCAPS). The final results reveal that the proposed hybrid L27 OA Taguchi-based GRA-MLR-GA approach has effectively optimized the device parameters in which SnO2:F thickness, SnO2:F donor density, ZnO thickness, ZnO donor density, CH3NH3PbI3-xClx thickness, CH3NH3PbI3-xClx donor density, Spiro-OMeTAD thickness and Spiro-OMeTAD acceptor density are predictively tuned at 0.198 μm, 8.973 x 1018 cm-3, 0.039 μm, 8.827 x 1017 cm-3, 0.386 μm, 1.929 x 1013 cm-3, 0.233 μm and 8.984 x 1018 cm-3 respectively. After the predictive modeling, both FF and PCE of the perovskite photovoltaic cell have been improved for ~5.93% and ~5.78% respectively.

TiO2 Sol-gel Coating as a Transducer Substrate for Impedimetric Immunosensors

Given the importance of the transducer elements in the performance of sensors for various applications, as well as the growing search for devices that are capable of providing the response in shorter time, in this work, titanium dioxide was examined as a candidate for application in an electrochemical biosensor. A TiO2 coating deposited by sol-gel method on a silicon wafer was obtained with an anatase crystalline structure, as an n-type<br /> semiconductor with donor density equal to 2.954 · 1017 cm–3. Its surface was functionalized to be tested as a biosensor to detect snake venom of the Bothrops genera, and each step of the functionalization was investigated using Electrochemical Impedance Spectroscopy (EIS) and Cyclic voltammetry. Despite being less sensitive than the reference method ELISA, the TiO2-based biosensor was also capable of detecting the analyte of interest at 20 μg mL–1, revealing an increase in its leakage resistance and phase shift after incubation in this solution. Furthermore, the total time for carrying out the biodetection with the TiO2-coated device (41.24 ± 0.05 min) was estimated to be approximately 80 % shorter than that required by the labelled standard assay, which indicates that TiO2 is a promising electrochemical transducer for biosensing applications.

Correlation between Defect Density and Corrosion Parameter of Electrochemically Oxidized Aluminum

It has been recognized that a connection may exist between defects of oxide coating and its corrosion protection. Such a link has not been substantiated. We prepare two coatings of anodized aluminum oxide (AAO) and plasma electrolytic oxidation (PEO), and analyze them with Mott-Schottky plots and potentiodynamic polarization scans. The as-grown and annealed AAO coatings exhibit both p-type and n-type semiconductor behaviors. Polarization resistance of the AAO coating increases from (1.8 ± 1.7) × 108 to (4.3 ± 0.5) × 108 Ω·cm2, while corrosion current decreases from (6.1 ± 3.6) × 10−7 to (2.3 ± 0.9) × 10−7 A·cm−2, as annealing temperature increases from room temperature to 400 °C. The parameter analysis on AAO indicates a positive correlation between corrosion current and donor density, a negative correlation between polarization resistance and donor density. The attempt on correlating corrosion potential gives rise to considerable deviation from a linear fit. The results suggest protection of AAO hinges on its donor density, not acceptor. On the PEO coatings, only the n-type behavior is observed. Intriguingly, the donor density of PEO coating is influenced by the annealing temperature of its pre-anodized layer. The most resistant PEO coating, with pre-anodized and 400 °C annealed AAO, exhibits polarization resistance (2.1 ± 0.4) × 109 Ω·cm2 and corrosion current (1.7 ± 0.4) × 10−8 A·cm−2.

Enhanced photoelectrochemical water splitting of hematite multilayer nanowire photoanodes by tuning the surface state via bottom-up interfacial engineering

Tuning the donor density and the surface state density of hematite multilayer nanowire photoanodes.