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Physical Properties of Crystalline Infrared Optical Materials
Published in Paul Klocek, Handbook of Infrared Optical Materials, 2017
James Steve Browder, Stanley S. Ballard, Paul Klocek
Notes: Lead selenide can be used in single-crystal or thin-film form. Crystals of lead selenide can be grown by a variety of methods, the most widely used being the Bridgman-Stockman method. Single crystals can be prepared by pulling from the melt (Czochralski technique) or by slow evaporation in a vacuum onto a substrate of the same crystal structure. Also, lead selenide has been useful as an IR detector. Diode lasers of this material have been reported to emit radiation at 6.5 µm.
Long-Term Non-Operating Reliability of Selected Electronic Products
Published in Judy Pecht, Michael Pecht, Long-Term Non-Operating Reliability of Electronic Products, 2019
Some important infrared components include lead selenide detectors, coolers, and optics. Infrared components may experience some effects of chipping and flaking or mirror and lens coatings and possible lead selenide detector damage if exposed to moisture during long-term storage. Hermetic seals will prevent corrosion of metal parts. While some component failures can also be traced to multi-environmental long-term storage, the sensitivity of some detectors increases with storage time.
Quantum Dots:
Published in Vineet Kumar, Praveen Guleria, Nandita Dasgupta, Shivendu Ranjan, Functionalized Nanomaterials II, 2021
Kulvinder Singh, Shikha Sharma
In another example, lead selenide quantum dots have also been synthesized by the same methodology (Čapek et al. 2015). The synthetic route of lead selenide quantum dots has been divided into three steps that include the preparation of a trioctylphosphineselenide solution, preparation of lead oleate solution, and finally the two solutions are mixed and allowed to treat at high temperature. The trioctylphosphine selenide solution is prepared by mixing selenium powder in trioctylphosphine under an inert atmosphere and stirred for 16 h. resulting in a change of color from yellow to colorless. The preparation of the lead solution is done by taking lead oxide and oleic acid in hexadecane and then heating to get a colorless solution. The two solutions are then added at an elevated temperature to a three-neck flask and then the desired amount of trioctylphosphine and diphenylphosphine are added. After a certain interval of time, the reaction temperature is decreased for the growth of quantum dots. To observe the quantum confinement effect, aliquots are taken from the reaction vessel after certain intervals of time. The precipitates are obtained by treating the sample with toluene, ethanol, and acetonitrile mixture. In the synthesis, trioctylphosphine and oleic acid lower the reaction rate, and diphenylphosphine increases the rate of formation of diphenylphosphineselenide. The size of quantum dots has been controlled with a decrease in the concentration of trioctylphosphine. A similar approach has been implemented for the fabrication of quantum dots of cadmium selenide (Kim et al.2014). In this synthetic route, the solution of selenium-triphenylphosphine is added to the solution of cadmium oleate, octadecene, and ocetylamine which is preheated at 250 °C that results in the formation of cadmium selenide quantum dots. In addition, numerous quantum dots have been prepared by the same approach that includes selenides of lead, cadmium, zinc, telluride of cadmium, and so on (Pu and Hsu 2014; Čapek et al. 2015; Moreels et al. 2011; Hou et al. 2014; Zhang et al. 2010; Gao et al. 2009; Bansal et al. 2016). Generally, the development of quantum dots is classified in two elementary stages, i.e. nucleation and growth of crystallite. When the reaction proceeds with the lowering of the free energy, homogenous nucleation takes place instinctively. Figure 9.10 displays the relation between free energy relationships with the nucleation of the crystallite.
Three decades of on-road mobile source emissions reductions in South Los Angeles
Published in Journal of the Air & Waste Management Association, 2019
In-use vehicle tailpipe exhaust measurements were collected with a remote sensor developed at the University of Denver named Fuel Efficiency Automobile Test (FEAT). The current instrument is composed of infrared (IR) and ultraviolet (UV) light sources placed on one side of the road with a detector unit on the opposite side. Four non-dispersive lead selenide IR sensors are used for a reference channel (3.9 μm), CO (3.6 μm), CO2 (4.3 μm) and HC (3.3 μm) in combination with two dispersive UV spectrometers connected via a quartz fiber coupling. The first spectrometer collects spectra for nitric oxide (NO), sulfur dioxide (SO2) and ammonia (NH3) between 198 and 227 nm while the second records nitrogen dioxide (NO2) spectra between 430 and 450 nm. The detectors sample at 100 Hz and the equipment and methodology has been fully described in the literature (Bishop and Stedman 1996; Burgard et al. 2006a; Burgard, Bishop, and Stedman 2006b).
Effect of oxygen annealing on the photoresponse of PbSe thin films fabricated by the pulsed laser deposition method
Published in Radiation Effects and Defects in Solids, 2018
Ramu Pasupathi Sugavaneshwar, Thang Duy Dao, Takahiro Yokoyama, Satoshi Ishii, Tadaaki Nagao
Among the semiconductor chalcogenides, lead selenide (PbSe) has the largest exciton Bohr radius (46 nm), which allows remarkable quantum confinement already in mesoscale crystals (1–3). In addition, the PbSe infrared (IR) detectors can maintain excellent detectivity in the IR region, even at room temperature, in contrast to the other IR detectors, such as HgCdTe detectors, which needs the operation at liquid nitrogen temperature. Thanks to these advantages, great interest and continuing investigations exist on the PbSe-based alloys (4–6).
Improving the thermoelectric figure of merit
Published in Science and Technology of Advanced Materials, 2021
One of the best ways of reducing the lattice thermal conductivity is the formation of a solid solution [6]. For example, the compound lead telluride is a useful thermoelectric generator material. Its figure of merit can be further improved by alloying it with the isomorphous compounds lead selenide or tin telluride. The disturbance of the short range order is effective in scattering phonons but the maintenance of the long range order means that the carrier mobility is unaffected.