Douglas Keszler | |
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Nationality | American |
Alma mater | Southwestern Oklahoma State University (B.S.) (1979) Northwestern University (Ph.D) (1984) |
Known for | Material Chemistry Inorganic Chemistry |
Scientific career | |
Fields | Chemistry |
Institutions | Oregon State University |
Doctoral advisor | James A. Ibers |
Website | chemistry |
Douglas A. Keszler is a distinguished professor in the Department of Chemistry at Oregon State University, adjunct professor in the Physics Department at OSU and adjunct professor in the Department of Chemistry at University of Oregon. [1] He is also the director of the Center for Sustainable Materials Chemistry, [2] and a member of the Oregon Nanoscience and Microtechnologies Institute (ONAMI) leadership team. [3]
Keszler received his BS at Southwestern Oklahoma State University in 1979. [1] He worked on his PhD in Northwestern University under the supervision of Prof. James A. Ibers and received his degree in 1984. He continued his career as a postdoctoral fellow at Cornell University under the supervision of Prof. Roald Hoffmann in 1984–1985. [4]
Keszler joined the faculty of Oregon State University in 1985 as an assistant professor. He became an associate professor in 1990, professor in 1995 and distinguished professor in 2006. [2]
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Some of Keszler’s early work shows the importance of his research in material science for application purposes. For example, in 2002, he worked on thin-film electroluminescent devices which display high definition monochromic color outputs, and developing them to display a full range of color. They specifically focused on phosphor Zn1-3x/2GaxS:Mn and strontium sulfide codoped with copper and potassium powders which was observed to have identical emission properties as thin films. Essentially by codoping, the band gap length of a material can be tuned so that the color of the light can be adjusted. The light itself is emitted when excited electrons in the conduction band fall back down to the valence band. By manipulating the properties of crystal and defect chemistry, any color can be portrayed for display. [5]
Keszler has also developed a convenient method for solid synthesis. In 2001, he demonstrated a hydrothermal dehydration technique of precipitates which avoids formation of amorphous products that are created through the conventional drying process of heating. Through this method, he showed the formation of Zn2SiO4 and SnSiO3. This technique has allowed for development of materials such as powders, thin films, and luminescent materials. [6]
In 2000, Douglas Keszler and his colleagues worked with non-linear optical materials such as Ca4GdO(BO3)3(GdCOB). They measured the Raman spectra of Ca4GdO(BO3)3(GdCOB) which was grown using the Czochralski method. This experiment was done to ultimately understand the spectroscopic features of Yb3+ and Nd3+ by analyzing vibrations of two different types of (BO3)3− groups. [7]
Keszler’s research group focuses on the synthesis and study of inorganic molecules and materials related to next-generation electronic and energy devices. Their discovery and development on water-based chemistries for high-quality films demonstrates the leading results in the field of ultra small-scale dense nanopatterning and tunneling electronic devices. One of their recent publication in 2014 focuses on amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) which are widely used in active-matrix organic light-emitting diode (AMOLED) applications, as well as active-matrix liquid crystal display (AMLCD) backplane applications. AMOLED is a display technology used in smartwatches, mobile devices, laptops, and televisions. OLED describes a specific type of think-film-display technology. TFT is a special kind of field-effect transistor made by depositing thin films of an active semiconductor layer as well as the dielectric layer and metallic contacts over a supporting but non-conducting substrate. Keszler's group discovered that indium gallium zinc oxide (IGZO) is a material-of choice for the replacement of hydrogenated silicon (a-Si:H) that is currently used in switching TFTs. [8] [9] IGZO comparing to hydrogenated silicon material has incredible advantages in the cost of synthesis.
Another aspect of Keszler's research demonstrates synthesis of functional inorganic materials such as high-quality inorganic films and ordered nanostructures with single-digit nanometer resolution in solution. In 2013, they came up with successful aqueous-based synthesis of ultrathin films of TiO2 and aqueous-derived Al4O3(PO4)2(AlPO) films and were able to assemble these materials into nanolaminates. [10] Keszler group’s successful synthesis of flat cluster [Al13(μ3-OH)6(μ2-OH)18(H2O)24]15+ using an electrochemical method and treating aqueous aluminum nitrate solution with a zinc metal powder at room temperature demonstrate the importance of his work to the field of water-based material synthesis. [6] From that, they focused more on developing aqueous-based synthesis of couple other compounds such as [Sc2(μ-OH)2(H2O)6(NO3)2](NO3)2] from an aqueous scandium nitrate solution. [11]
Douglas Keszler has received a number of awards and honors, including the following:
A borate is any of a range of boron oxyanions, anions containing boron and oxygen, such as orthoborate BO3−3, metaborate BO−2, or tetraborate B4O2−7; or any salt of such anions, such as sodium metaborate, Na+[BO2]− and borax (Na+)2[B4O7]2−. The name also refers to esters of such anions, such as trimethyl borate B(OCH3)3.
A thin-film transistor (TFT) is a special type of field-effect transistor (FET) where the transistor is made by thin film deposition. TFTs are grown on a supporting substrate. A common substrate is glass, because the traditional application of TFTs is in liquid-crystal displays (LCDs). This differs from the conventional bulk metal oxide field effect transistor (MOSFET), where the semiconductor material typically is the substrate, such as a silicon wafer.
Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main source of iron for the steel industry. Fe2O3 is readily attacked by acids. Iron(III) oxide is often called rust, and to some extent this label is useful, because rust shares several properties and has a similar composition; however, in chemistry, rust is considered an ill-defined material, described as hydrous ferric oxide.
Lead(II) nitrate is an inorganic compound with the chemical formula Pb(NO3)2. It commonly occurs as a colourless crystal or white powder and, unlike most other lead(II) salts, is soluble in water.
Copper(II) nitrate describes any member of the family of inorganic compounds with the formula Cu(NO3)2(H2O)x. The hydrates are blue solids. Anhydrous copper nitrate forms blue-green crystals and sublimes in a vacuum at 150-200 °C. Common hydrates are the hemipentahydrate and trihydrate.
Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2. It forms hydrates. Zinc chloride, anhydrous and its hydrates are colorless or white crystalline solids, and are highly soluble in water. Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride. This salt is hygroscopic and even deliquescent. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O.
Arsenous acid (or arsenious acid) is the inorganic compound with the formula H3AsO3. It is known to occur in aqueous solutions, but it has not been isolated as a pure material, although this fact does not detract from the significance of As(OH)3.
Lanthanum(III) oxide, also known as lanthana, chemical formula La2O3, is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts, among other uses.
Sodium perborate is chemical compound whose chemical formula may be written NaH2BO4, Na2H4B2O8, or, more properly, [Na+]2[B2O4(OH)4]2−. Its name is sometimes abbreviated as PBS.
Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide can be found as a colorless amorphous powder or as brown or red crystals. Cadmium oxide is an n-type semiconductor with a band gap of 2.18 eV at room temperature.
Sodium hexanitritocobaltate(III) is inorganic compound with the formula Na3[Co(NO2)6]. The anion of this yellow-coloured salt consists of the transition metal nitrite complex [Co(NO2)6]3−. It was a reagent for the qualitative test for potassium and ammonium ions.
Gallium(III) oxide is an inorganic compound and ultra-wide-bandgap semiconductor with the formula Ga2O3. It is actively studied for applications in power electronics, phosphors, and gas sensing. The compound has several polymorphs, of which the monoclinic β-phase is the most stable. The β-phase’s bandgap of 4.7–4.9 eV and large-area, native substrates make it a promising competitor to GaN and SiC-based power electronics applications and solar-blind UV photodetectors. The orthorhombic ĸ-Ga2O3 is the second most stable polymorph. The ĸ-phase has shown instability of subsurface doping density under thermal exposure. Ga2O3 exhibits reduced thermal conductivity and electron mobility by an order of magnitude compared to GaN and SiC, but is predicted to be significantly more cost-effective due to being the only wide-bandgap material capable of being grown from melt. β-Ga2O3 is thought to be radiation-hard, which makes it promising for military and space applications.
Indium(III) oxide (In2O3) is a chemical compound, an amphoteric oxide of indium.
Iron(III) nitrate, or ferric nitrate, is the name used for a series of inorganic compounds with the formula Fe(NO3)3.(H2O)n. Most common is the nonahydrate Fe(NO3)3.(H2O)9. The hydrates are all pale colored, water-soluble paramagnetic salts.
Bromous acid is the inorganic compound with the formula of HBrO2. It is an unstable compound, although salts of its conjugate base – bromites – have been isolated. In acidic solution, bromites decompose to bromine.
Indium gallium zinc oxide (IGZO) is a semiconducting material, consisting of indium (In), gallium (Ga), zinc (Zn) and oxygen (O). IGZO thin-film transistors (TFT) are used in the TFT backplane of flat-panel displays (FPDs). IGZO-TFT was developed by Hideo Hosono's group at Tokyo Institute of Technology and Japan Science and Technology Agency (JST) in 2003 and in 2004. IGZO-TFT has 20–50 times the electron mobility of amorphous silicon, which has often been used in liquid-crystal displays (LCDs) and e-papers. As a result, IGZO-TFT can improve the speed, resolution and size of flat-panel displays. It is currently used as the thin-film transistors for use in organic light-emitting diode (OLED) TV displays.
Indium(III) hydroxide is the chemical compound with the formula In(OH)3. Its prime use is as a precursor to indium(III) oxide, In2O3. It is sometimes found as the rare mineral dzhalindite.
Bismuth oxynitrate is the name applied to a number of compounds that contain Bi3+, nitrate ions and oxide ions and which can be considered as compounds formed from Bi2O3, N2O5 and H2O. Other names for bismuth oxynitrate include bismuth subnitrate and bismuthyl nitrate. In older texts bismuth oxynitrate is often simply described as BiONO3 or basic bismuth nitrate. Bismuth oxynitrate was once called magisterium bismuti or bismutum subnitricum, and was used as a white pigment, in beauty care, and as a gentle disinfectant for internal and external use. It is also used to form Dragendorff's reagent, which is used as a TLC stain.
Terbium compounds are compounds formed by the lanthanide metal terbium (Tb). Terbium generally exhibits the +3 oxidation state in these compounds, such as in TbCl3, Tb(NO3)3 and Tb(CH3COO)3. Compounds with terbium in the +4 oxidation state are also known, such as TbO2 and BaTbF6. Terbium can also form compounds in the 0, +1 and +2 oxidation states.
Cobalt compounds are chemical compounds formed by cobalt with other elements.