Carl M. Lampert

Bio: Carl M. Lampert is an academic researcher from Lawrence Berkeley National Laboratory. The author has contributed to research in topics: Electrochromism & Electrochromic devices. The author has an hindex of 16, co-authored 34 publications receiving 1267 citations.

Heat mirror coatings for energy conserving windows

Abstract: Heat-mirror coatings are important as transparent insulation for a host of applications, including building window glazings. They reduce thermal emittance of glass and polymeric substrates, thereby decreasing the effective radiative loss of a glazing or window assembly. Properties of coatings and substrates, as well as various window designs, are detailed. The paper reviews heat-mirror deposition technology including chemical vapor deposition using hydrolysis and pyrolysis reactions, dc and rf sputtering using reactive, biased and nonreactive techniques, vapor deposition and ion plating. The properties of single-layer films including coatings of In 2 O 3 :Sn, doped SnO 2 , Cd 2 SnO 4 , noble and transition metal films are enumerated. Multilayer films described include dielectric overcoated metals such as ZnS/metal/ZnS, Bi 2 O 3 /Au/Bi 2 O 3 and TiO 2 /Ag/TiO 2 . Electrical, solar and infrared radiative properties are tabulated. Much of the data presented is also useful for photovoltaic and collector applications. New and innovative materials systems are suggested.

Effect of deposition pressure on the microstructure and electrochromic properties of electron-beam-evaporated nickel oxide films

Abstract: Electron-beam-evaporated nickel oxide films were shown to have a microcrystalline cubic nickel oxide structure. The pressure in the chamber during the film deposition has a large effect on the crystal size and the stoichiometry of the films. The redox currents, the efficiency of these films to color, and their optical properties were influenced by the processing conditions employed and the resulting microstructure. A model is proposed based on the observed microstructure that explains the source of overstoichiometric oxygen and ion transport in these films.

Preparation and properties of spin-coated Nb2O5 films by the sol-gel process for electrochromic applications

Abstract: The preparation and properties of Nb2O5 coatings made by the sol-gel process were investigated. The films were deposited by spin coating on In2O3:Sn/glass and quartz substrates from a polymeric solutions of niobia derived from niobium ethoxide. The films were characterized by investigation of the stoichiometry, refractive index, optical transmission, electrochemical behavior, and the microstructure. X-ray diffraction studies showed the films to be amorphous for heat treatments below 450°C. X-ray photoelectron spectroscopy (XPS) measurement revealed the O:Nb atomic stoichiometry to be 5:2. Cyclic voltammetric measurements showed that the Nb2O5/1M LiClO4-propylene carbonate system exhibits electrochemical reversibility beyond 1 200 cycles without change in performance. In situ UV-Vis-NIR spectroelectrochemical measurement revealed that Nb2O5 films exhibit an electrochromic effect in the spectral range 300<λ<2100 nm and remain unchanged in the infrared spectral range. The change in visible transmittance was 40% for a 250 nm thick electrode. XPS spectra indicate that Nb(V) is reduced to a lower valence state Nb(IV) in a colored state with injected Li+. The bronze coloration is due to a simultaneous injection of electrons and Li+ ions into Nb2O5. The sol-gel-deposited Nb2O5 films are useful for cathodically coloring electrochromic electrodes in electrochromic devices.

Optical and electrochemical characteristics of niobium oxide films prepared by sol-gel process and magnetron sputtering A comparison

Abstract: Electrochromic niobia (Nb205) coatings were prepared by the sol-gel spin-coating and d.c. magnetron sputtering techniques. Parameters were investigated for the process fabrication of sol-gel spin coated Nb205 films exhibiting high coloration efficiency comparable with that d.c. magnetron sputtered niobia films. X-ray diffraction studies (XRD) showed that the sol-gel deposited and magnetron sputtered films heat treated at temperatures below 450°C, were amorphous, whereas those heat treated at higher temperatures were slightly crystalline. X-ray photoelectron spectroscopy (XPS) studies showed that the stoichiometry of the films was Nb205. The refractive index and electrochromic coloration were found to depend on the preparation technique. Both films showed low absorption and high transparency in the visible range. We found that the n, k values of the sol-gel deposited films to be lower than for the sputtered films. The n and k values were n = 1.82 and k = 3 × 10 -3, and n = 2.28 and k = 4 × 10 -3 at 530 nm for sol-gel deposited and sputtered films, respectively. The electrochemical behavior and structural changes were investigated in 1 M LiC1On/propylene carbonate solution. Using the electrochemical measurements and X-ray photoelectron spectroscopy, the probable electrode reaction with the lithiation and delithiation is Nb205 + x Li++x e-~ LixNb205. Cyclic voltametric (CV) measurements showed that both Nb205 films exhibits electrochemical reversibility beyond 1200 cycles without change in performance. "In situ" optical measurement revealed that those films exhibit an electrochromic effect in the spectral range 300 < h < 2100 nm but remain unchanged in the infrared spectral range. The change in visible transmittance was 40% for 250 nm thick

Microstructure on a black chrome solar selective absorber

Abstract: Presented at the SPIE 22nd International Technical Symposium, San Diego, CA, August 28 - 31, 1978 LBL-8022c, d- 'j l MICROSTRUCTURE OF A BLACK.CHROME SOLAR SELECTIVE ABSORBER Carl M. Lamper1: RECETVED I..AWRENCF. SEP'KfLEY i.ABORAJORY August 1978 OCT 3 1978 LiBRARY AND DOCUMENTS SECTION Prepared for. the U. S. Department of Energy under Contract W-7405~ENG-48

Evaporated Sn‐doped In2O3 films: Basic optical properties and applications to energy‐efficient windows

Abstract: We review work on In2O3:Sn films prepared by reactive e‐beam evaporation of In2O3 with up to 9 mol % SnO2 onto heated glass. These films have excellent spectrally selective properties when the deposition rate is ∼0.2 nm/s, the substrate temperature is ≳150 °C, and the oxygen pressure is ∼5×10−4 Torr. Optimized coatings have crystallite dimensions ≳50 nm and a C‐type rare‐earth oxide structure. We cover electromagnetic properties as recorded by spectrophotometry in the 0.2–50‐μm range, by X‐band microwave reflectance, and by dc electrical measurements. Hall‐effect data are included. An increase of the Sn content is shown to have several important effects: the semiconductor band gap is shifted towards the ultraviolet, the luminous transmittance remains high, the infrared reflectance increases to a high value beyond a certain wavelength which shifts towards the visible, phonon‐induced infrared absorption bands vanish, the microwave reflectance goes up, and the dc resisitivity drops to ∼2×10−4 Ω cm. The corre...

Past achievements and future challenges in the development of optically transparent electrodes

Abstract: Increasing demand for raw materials means that alternatives to indium-tin oxide are desired for optically transparent electrode applications. Carbon nanotube, metal nanowire networks and regular metal grids have been investigated as possible options. In this review, these materials and recently rediscovered graphene are compared with the usual transparent conductive oxides.

Electrochemically Active Polymers for Rechargeable Batteries.

Abstract: Electrochemical energy storage systems (batteries) have a tremendous role in technical applications In this review the authors examine the prospects of electroactive polymers in view of the properties required for such batteries Conducting organic polymers are considered here in the light of their rugged chemical environment: organic solvents, acids, and alkalis The goal of the present article is to provide, first of all in tabular form, a survey of electroactive polymers in view of potential applications in rechargeable batteries It reviews the preparative methods and the electrochemical performance of polymers as rechargeable battery electrodes The theoretical values of specific charge of the polymers are comparable to those of metal oxide electrodes, but are not as high as those of most of the metal electrodes normally used in batteries Therefore, it is an advantage in conventional battery designs to use the conducting polymer as a positive electrode material in combination with a negative electrode such as Li, Na, Mg, Zn, MeH{sub x}, etc 504 refs

Transparent conductors as solar energy materials: A panoramic review

Abstract: Transparent conductors (TCs) have a multitude of applications for solar energy utilization and for energy savings, especially in buildings. The largest of these applications, in terms of area, make use of the fact that the TCs have low infrared emittance and hence can be used to improve the thermal properties of modern fenestration. Depending on whether the TCs are reflecting or not in the near infrared pertinent to solar irradiation, the TCs can serve in “solar control” or “low-emittance” windows. Other applications rely on the electrical conductivity of the TCs, which make them useful as current collectors in solar cells and for inserting and extracting electrical charge in electrochromic “smart windows” capable of combining energy efficiency and indoor comfort in buildings. This Review takes a “panoramic” view on TCs and discusses their properties from the perspective of the radiative properties in our ambience. This approach leads naturally to considerations of spectral selectivity , angular selectivity , and temporal variability of TCs, as covered in three subsequent sections. The spectrally selective materials are thin films based on metals (normally gold or titanium nitride) or wide band gap semiconductors with heavy doping (normally based on indium, tin, or zinc). Their applications to energy-efficient windows are covered in detail, experimentally as well as theoretically, and briefer discussions are given applications to solar cells and solar collectors. Photocatalytic properties and super-hydrophilicity are touched upon. Angular selective TCs, for which the angular properties are caused by inclined columnar nanostructures, are then covered. A discussion of TC-like materials with thermochromic and electrochromic properties follows in the final part. Detailed treatments are given for thermochromic materials based on vanadium dioxide and for electrochromic multi-layer structures (incorporating TCs as essential components). The reference list is extensive and aims at giving an easy entrance to the many varied aspects of TCs.

Electrochromic tungsten oxide films: Review of progress 1993–1998

Abstract: W oxide films are of critical importance for electrochromic device technology, such as for smart windows capable of varying the throughput of visible light and solar energy. This paper reviews the progress that has taken place since 1993 with regard to film deposition, characterization by physical and chemical techniques, optical properties, as well as electrochromic device assembly and performance. The main goal is to provide an easy entrance to the relevant scientific literature.