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Smart Sensors for Digital Agriculture
Published in Indu Bala, Kiran Ahuja, Harnessing the Internet of Things (IoT) for a Hyper-Connected Smart World, 2023
Optoelectronics is the field of electronics with devices that source, detect, and control light. The light thus releases electrons from a semiconductor or metal surface, and, if there is an external electric field, the free charge carriers thus generated result in a photometric current proportional to the intensity of the light [44]. These sensors can distinguish between entities based on the reflection spectra and are used for mapping for instance, mapping the distribution of weed with the position [45, 46].
Visual Performance
Published in Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe, Visual and Non-Visual Effects of Light, 2020
Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe
Nowadays we can distinguish three types of solid-state light sources: LEDs (light-emitting diodes), OLEDs (organic light-emitting diodes), and PLEDs (polymer light-emitting diodes). An LED is a semiconductor optoelectronic device that emits semi-monochromatic (narrow band) radiation from a wide optical radiation spectrum range, including visible, infrared, and ultraviolet radiation. LEDs emit radiation in a narrow band which is described as a Gaussian-shape. It is characterized by two parameters: the peak wavelength corresponding to the highest emitted radiant flux, and the full width half maximum bandwidth (FWHM) corresponding to the difference in wavelength at which the emitted radiant flux reaches half of the maximum value. The typical value of FWHM is approximately 25 nm. For the production of LEDs, many different materials are used (Al, As, Ga, In, N, P, Se, Si, Zn), allowing the emission of radiation bands with different peak wavelengths [Rea 2000; van Bommel 2019].
Medical Applications
Published in Dave Birtalan, William Nunley, Optoelectronics, 2018
Optoelectronic devices consist of a light-emitting diode (ultraviolet, visible, or near-infrared led) and photosensor (photodiode, phototransistor, or Photologic device). The LED emits a light at a specified wavelength, and the photosensor receives the light and provides an output signal to be evaluated. As light is transmitted from the LED through a tube that contains air or another gas, the photosensor receives photons at a consistent level. The internal walls of the tube reflect some of the light, thus reducing the number of photons received by the photosensor. When a fluid is present in the tube, the number of photons received changes, resulting in a change in the output of the photosensor. This change in output is what allows the user to identify the states mentioned earlier as well as the type of fluid in the tube.
Be2C monolayer as an efficient adsorbent of toxic volatile organic compounds: theoretical investigation
Published in Molecular Physics, 2022
Hossein Farrokhpour, Mehrdad Gerami, Hamidreza Jouypazadeh
Numerous two-dimensional nanomaterials including metals, nitrous oxides, and carbides with special electronic properties have been used for a wide range of applications in photocatalysts [63], energy storage [64], nanoelectronics [65], and sensing [66]. Recently, Li et al. designed a novel two-dimensional (2D) inorganic material, namely Be2C monolayer, by comprehensive density functional theory (DFT) calculations. In the structure of Be2C monolayer, each carbon atom is connected to six Be atoms in an almost planar fashion, forming a quasi-planar hexacoordinate carbon (phC) moiety [67]. As a semiconductor with a direct medium band gap, the Be2C monolayer is promising for applications in electronics and optoelectronics [68]. Our aim in this study is to investigate the ability of the Be2C monolayer for the adsorption of the conventional toxic VOCs including formaldehyde (CH2O), acetaldehyde (C2H4O), vinyl chloride (C2H3Cl), and benzene (C6H6). The adsorption of the molecules on the Be2C monolayer is performed in their isolated forms and their co-adsorption with one water molecule, separately. Also, the absorption spectra of the complexes (monlayer + adsorbate) in the absence of the water molecule are calculated and compared with that of the bare monolayer to investigate its potential for sensing via absorption spectroscopy.
Exploring the effect of oligothiophene and acene cores on the optoelectronic properties and enhancing p- and n-type ability of semiconductor materials
Published in Journal of Sulfur Chemistry, 2021
Ahmad Irfan, Muhammad Imran, Renjith Thomas, Muhammad Asim Raza Basra, Sami Ullah, Abdullah G. Al-Sehemi, Mohammed A. Assiri
Due to their carrier mobility properties, organic semiconductor materials (OSMs) have triggered research work in utilizing them in applications for energy conversion, organic light emitting diodes, optoelectronics and photovoltaics [1]. Recently organic optoelectronics has evolved numerous devices within organic light-emitting diodes (OLEDs) along with organic field-effect transistors (OFETs) [2–4]. Aromatic compounds gained too much interest for synthetic as well as theoretical chemists [5] based on their broad range applications as organic semiconductors [6–10]. The recent research within polycyclic conjugated hydrocarbons (PCHs) has broadened their application in organic electronics industry rapidly as well as to produce new functional compounds instead of inorganic solids [11–17]. The extended conjugation and optoelectronic characteristics in PCHs (e.g. polyacenes) made them attractive as OSMs. As they are unstable, many longer polyacenes dimerize, and photo-oxidize quickly in the air unless they are adequately stabilized [18]. Keeping in mind, the problems there is a need to synthesize polyacene substituents having better stability along with promising electronic characteristics.
Novel method for the determination of the optical conductivity and dielectric constant of SiGe thin films using Kato-Adachi dispersion model
Published in Phase Transitions, 2021
Emna Kadri, Khaled Dhahri, Régis Barillé, Mohamed Rasheed
This variety of applications is mainly due to the tunable band gaps of thin films, to their lattices and strains as they can be tuned to match III–V semiconductors [4]. In addition, the implementations of on Si is notably attractive since it permits to control the band gap as well as the fine material properties such as the refractive index by matching the Ge concentration in the alloy. Recently, the Si-based technologies have demonstrate important prospective for the implementation of new mid-infrared (IR) photonic circuits. Hence, the actuality of our study is mainly roused by the fact that mid-IR based Si1-xGex devices have recently acquired importance due to the gigantic number of applications predictable over the 2–20μm wavelength range [5]. Therefore, the growth and characterization of thin films have been actively investigated for its promising semiconductor device applications in the electronics as well as optoelectronics operating in the visible and infrared region of the light spectrum. Recently, they have become a timely topic due to their capability to generate high-frequency microwave materials on Si [6]. However, one have to disentangle that for x lying between x = 0.05 and x = 0.1, a bulky lattice mismatches about 2.0–4.5% is observed between thin films and Si (001) giving rise to a relaxation of the thin films via serious ‘island growth’ [7].