U 3900

The optical transmission was carried out by a double-beam spectrophotometer (U-3900, U-3900, Hitachi, Ltd., Tokyo, Japan). The surface morphology was measured by an atomic force microscope (AFM; nanonaviSPA-400 SPM, SII Nano Technology Inc., Chiba, Japan). The AFM measurement mode used was the tapping mode. The parameters of the AFM tip (Tap150AL-G, Innovative Solutions Bulgaria Ltd., Sofia, Bulgaria) were resonant frequency: 150 KHz and force constant: 5 N/m. The measurement geometry was rectangle and the acquisition time was 4 min. Fourier Transform Infrared Spectroscopy (FTIR) was carried out by the Nicolet 5700. The chemical composition of the thin film was analyzed by X-ray photoelectron spectroscopy (XPS, Thermo Scientific K-Alpha+, Thermo Fisher Scientific Inc., Waltham, MA, USA). The crystal structure of the thin film was investigated by X-ray diffraction (XRD, Rigaku D/max-rB, Rigaku Corporation, Tokyo, Japan). The electrical properties were measured by a semiconductor parameter analyzer (Keithley 4200, Tektronix Inc., Beaverton, OR, USA).
The field-effect mobility (μ) and SS were extracted by using the following equations [13 (link)]
$$I_{\mathrm{D}}=(\frac{W}{2L}{C}_{\mathrm{i}}\mu ){(V_{\mathrm{G}}-V_{\mathrm{th}})}^2$$
$$SS=\frac{d{V}_{\mathrm{G}}}{d(Log{I}_{\mathrm{D}})}$$
where W and L are the channel width and length, respectively. C_i is the capacitance per unit area of the insulator; V_th is the threshold voltage; and V_G is the gate voltage.

The glucose detection experiments using the MOI developed in this study were conducted in a dark room. First, six different concentrations (0.01–0.1 M) of ammonium metavanadate sulfuric acid detection solution were prepared, and the optimal detection liquid concentration was confirmed by diluting hydrogen peroxide 1000 times. After preparing the detection liquid, 5 mg/mL of glucose oxidase and seven different concentrations (0.1–10 mM) of glucose were catalyzed and reacted at 37 °C. To detect the glucose concentrations, HITACHI U-3900 was used to measure the results at different concentrations. Next, a micro-optical instrument was designed using FC blue Mini-LEDs as the light source, combined with fiber optics, collimating lenses, and a micro-spectrometer to measure and analyze the glucose concentrations. Finally, the glucose concentration measurement results obtained using the HITACHI U-3900 and the FC blue Mini-LEDs MOI were compared.

The chlorophyll contents (chlorophyll a, b, and total chlorophyll) of maize leaves exposed to EGC in the net house condition were estimated by using the dimethyl sulfoxide (DMSO) method (Hiscox and Israelstam, 1979 (link); Barnes et al., 1992 (link)). Fully exposed and matured leaves (5th leaves from the ground) were collected and rinsed with sterile water. A sample of 0.5 g was weighed and immediately immersed in 10 ml of DMSO followed by incubation in a hot air oven (80°C) for 4 h. After the complete digestion, 1 ml of the extract was diluted with 5 ml DMSO, and the absorbance was documented using a spectrophotometer (Hitachi, U-3900, Version 2J2530004, Japan) at 645 and 663 nm wavelengths keeping DMSO as a blank. The chlorophyll content was calculated by using Arnon (1949 (link)) formula.
where OD is the absorbance, V is the volume of DMSO used for the extraction of pigments, DF is the dilution factor, and W is the weight of the sample (g). The chlorophyll content was expressed in terms of mg g⁻¹ FW.
The same extract was used for the estimation of carotenoid content under EGC stress (Kirk and Allen, 1965 (link)). The spectrophotometer reading (Hitachi, U-3900, Version 2J2530004, Japan) was recorded at 480 nm, and the carotenoid content was calculated using the following formula and expressed in terms of μg g⁻¹ FW.
where OD is the absorbance recorded at 480, 663, and 645 nm.