In this paper, we determine the optical refractive indices of different molarities of glucose using nano-laminated gold/chromium (Au-Cr) thin film via Kretschmann-based Surface Plasmon Resonance (K-SPR) sensing with angular interrogation. The nano-laminated Au-Cr K-SPR sensor detects the glucose presence in low-and high-concentration of 4-12 mmol/L and 55-277 mmol/L, respectively, under the exposure of 670 nm and 785 nm optical wavelengths. The experimental results showed that the minimum limit of detection (LOD) of Au-Cr K-SPR is 4 mmol/L and the glucose sensor sensitivities are in average of 3.41 o /M and 2.73 o /M at 670 nm and 785 nm optical wavelength, respectively. Stable sensitivity for each concentration also shown from the sensorgram results, indicates the stable performance of nanolaminated Au-Cr SPR sensor to detect glucose in the range from mmol/L up to dmol/L. Values of refractive indices for glucose molarities obtained are 1.33187 (4 mmol/L) and 1.3191 (4 mmol/L) at 670 and 785 nm wavelength, respectively. These RI values are beneficial for numerical simulation of glucose sensors using nano-laminated Au-Cr thin films which have been reported for the first time. The sensor can be eventually deployed in integrated photonic sensing devices comprising of multiple analyte detection for lab-on-chip (LoC) and point-of care (PoC) applications.
In the third generation of the solar cell era, significant trends in the development of perovskite solar cells (PSC) were observed. Exploring suitable materials for its wafer structure, such as perovskite and electron transport layers (ETL), were a major emphasis of high-performance PSC development. Because of its matching band structure to MaPbI3, TiO2 is the most often utilized material for ETL. However, in the application of TiO2 to PSC, electron trapping and a wide energy gap become a drawback. The goal of this research is to improve the absorption performance of PSC employing ETL with Fe and Ta-doped TiO2 as well as the thickness of the material. The interaction between the electromagnetic waves of light and the solar cell structure was calculated using Finite-Difference Time-Domain (FDTD) simulations, which resulted in the absorption spectra. In comparison to pure TiO2, which absorbs only 79.5% of the incident light, Fe-TiO2 and Ta-TiO2 as ETL in solar cells have increased absorption spectra to 81.7% and 81.2%, respectively. Finally, we may conclude that the optimum ETL layer parameters are 0.32% Fe doping and a thickness of 100 nm.
The properties of light and its interaction with biological analytes have made it possible to design sophisticated and reliable optical-based biomedical sensors. In this paper, we report the simulation, design, and fabrication of microring resonator (MRR)-based sensors for the detection of diabetic glucose levels. Electron Beam Lithography (EBL) with 1:1 hydrogen silsesquioxane (HSQ) negative tone resist were used to fabricate MRR on a Silicon-on-Insulator (SOI) platform. Scanning Electron Microscopy (SEM) was then used to characterize the morphology of the MRR device. The full-width at half-maximum (FWHM) and quality factors of MRR were obtained by using a tunable laser source (TLS) and optical spectrum analyzer (OSA). In this paper, the three-dimensional Finite Difference Time Domain (3D FDTD) approach has been used to simulate the proposed design. The simulation results show an accurate approximation with the experimental results. Next, the sensitivity of MRR-based sensors to detect glucose levels is obtained. The sensitivity value for glucose level detection in the range 0% to 18% is 69.44 nm/RIU. This proved that our MRR design has a great potential as a sensor to detect diabetic glucose levels.
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