01350nas a2200181 4500008004100000245007700041210006900118260001200187300001400199490000700213520076000220100002100980700001901001700002501020700002301045700002301068856007701091 1998 eng d00aOptical Constants of Sputter-Deposited Ti-Ce Oxide and Zr-Ce Oxide Films0 aOptical Constants of SputterDeposited TiCe Oxide and ZrCe Oxide  c09/1998 a5993-60010 v373 a

Films of Ti oxide, Zr oxide, Ce oxide, Ti-Ce oxide, and Zr-Ce oxide were made by means of reactive dc magnetron sputtering in a multitarget arrangement. The films were characterized by x-ray diffraction and electrochemical measurements, both techniques being firmly connected to stoichiometric information. The optical constants n and k were evalued from spectrophotometry and from variable-angle spectroscopic ellipsometry. The two analyses gave consistent results. It was found that n for the mixed-oxide films varied smoothly between the values for the pure oxides, whereas k in the band-gap range showed characteristic differences between Ti-Ce oxide and Zr-Ce oxide. It is speculated that this difference is associated with structural effects.

1 aVeszelei, Monica1 aKullman, Lisen1 aGranqvist, Claes, G.1 avon Rottkay, Klaus1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/optical-constants-sputter-deposited01789nas a2200205 4500008004100000245005300041210005300094260001200147300001000159490000800169520118600177653001801363653002901381653001901410653001901429100002301448700002301471700001701494856007201511 1996 eng d00aOptical Indices of Electrochromic Tungsten Oxide0 aOptical Indices of Electrochromic Tungsten Oxide c08/1997 a10-160 v3063 a

Tungsten trioxide (WO3) is the most widely used material for the active layer of electrochromic devices. Knowledge of the complex refractive index over the range of coloration states is required for device design. Optical constants of WO3 over the whole solar spectrum were determined as a function of injected charge. Films of WO3 were prepared by electron-beam evaporation, then colored in several steps by reduction with lithium (Li) up to 68 mC cm-2 µm-1 injected charge. Measurements included variable-angle spectroscopic ellipsometry and spectroscopic transmittance and reflectance at normal incidence. Analysis was complicated by the fact that a transparent-conducting layer of indium tin oxide (ITO) was required to perform lithiation. Optical indices of the glass substrate and ITO transparent conductor were determined separately and then fixed in the model. The indices of WO3 could then be extracted from measurements on the complete structure. A parametric dispersion model corresponding to Gaussian broadening of the oscillators was used to represent the dielectric response of WO3.

10aColored state10aComplex refractive index10aelectrochromic10atungsten oxide1 avon Rottkay, Klaus1 aRubin, Michael, D.1 aWen, Shi-Jie uhttps://facades.lbl.gov/publications/optical-indices-electrochromic02176nas a2200181 4500008004100000245005500041210005500096260001200151300001000163490000700173520164100180100002301821700002301844700001701867700001901884700002401903856006701927 1996 eng d00aOptical Indices of Lithiated Electrochromic Oxides0 aOptical Indices of Lithiated Electrochromic Oxides c07/1998 a49-570 v543 a

Optical indices have been determined for thin films of several electrochromic oxide materials. One of the most important materials in electrochromic devices, WO3, was thoroughly characterized for a range of electrochromic states by sequential injection of Li ions. Another promising material, Li0.5Ni0.5O, was also studied in detail. Less detailed results are presented for three other common lithium-intercalating electrochromic electrode materials: V2O5, LiCoO2, and CeO2-TiO2. The films were grown by sputtering, pulsed laser deposition (PLD) and sol-gel techniques. Measurements were made using a combination of variable-angle spectroscopic ellipsometry and spectroradiometry. The optical constants were then extracted using physical and spectral models appropriate to each material. Optical indices of the underlying transparent conductors, determined in separate studies, were fixed in the models of this work. The optical models frequently agree well with independent physical measurements of film structure, particularly surface roughness by atomic force microscopy. Inhomogeneity due to surface roughness, gradient composition, and phase separation are common in both the transparent conductors and electrochromics, resulting sometimes in particularly complex models for these materials. Complete sets of data are presented over the entire solar spectrum for a range of colored states. This data is suitable for prediction of additional optical properties such as oblique transmittance and design of complete electrochromic devices.

1 aRubin, Michael, D.1 avon Rottkay, Klaus1 aWen, Shi-Jie1 aÖzer, Nilgün1 aSlack, Jonathan, L. uhttps://facades.lbl.gov/publications/optical-indices-lithiated01218nas a2200145 4500008004100000050001400041245004900055210004800104260003100152490000800183520075800191100002300949700002300972856007700995 1996 eng d aLBL-3858600aOptical Indices of Pyrolitic Tin-Oxide Glass0 aOptical Indices of Pyrolitic TinOxide Glass aSan Francisco, CAc04/19960 v4263 a

SnO2:F is a widely used transparent conductor and commercially available in a multilayer structure as Tech glass. Current applications include photovoltaics, electrochromics and displays. Optical design of these and other applications requires knowledge of the optical constants, in some cases, over the whole solar spectrum. Various optical property measurements were performed including variable angle spectroscopic ellipsometry, and spectral transmittance and reflectance measurements. This material is deposited in several steps and has a fairly complex structure. The measured data were fit to models based on this structure to obtain the optical indices. Atomic force microscopy confirmed the optically modeled surface roughness.

1 avon Rottkay, Klaus1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/optical-indices-pyrolitic-tin-oxide01797nas a2200145 4500008004100000050001500041245005700056210005700113260002700170520132200197100002301519700002301542700001901565856006701584 1996 eng d aLBNL-3959400aOptical Modeling of a Complete Electrochromic Device0 aOptical Modeling of a Complete Electrochromic Device aSan Diego, CAc10/19963 a

Optical indices have been determined for thin films of all materials needed to model a typical electrochromic device. Two electrochromic materials, tungsten oxide and lithium nickel oxide, are widely used in electrochromic devices. The optical indices of the underlying transparent conductors as well as a polymer electrolyte were also analyzed. The optical data was obtained using a combination of variable-angle spectroscopic ellipsometry and spectroradiometry. The data was then fit to appropriate models of structure and dispersion in order to extract the optical indices of the materials. First, the optical indices of the transparent conductive substrates were obtained and fixed in the model. The best models correspond well to independent physical measurements of film structure, such as atomic-force microscopy and surface profiling. Surface roughness, gradient composition and other types of inhomogeneity are common in both the transparent conductors and electrochromic, resulting in particularly complex models. The polymer has a homogeneous structure, but obtaining optically smooth surfaces was a problem. Complete sets of data were produced over the entire solar spectrum for a range of colored states of the films. Using the data for each layer, a realistic electrochromic device was simulated.

1 avon Rottkay, Klaus1 aRubin, Michael, D.1 aKerr, John, B. uhttps://facades.lbl.gov/publications/optical-modeling-complete01683nas a2200157 4500008004100000050001400041245009300055210006900148300001200217490000800229520114900237100002301386700002301409700001901432856007401451 1995 eng d aLBL-3804200aOptical Indices of the Tin-doped Indium Oxide and Tungsten Oxide Electrochromic Coatings0 aOptical Indices of the Tindoped Indium Oxide and Tungsten Oxide  a551-5560 v4033 a

Thin films of tin-doped indium oxide are widely used for transparent conductors. One application of In2O3:Sn (ITO) is transparent contacts for electrochromic electrodes. Optical design of electrochromic devices requires knowledge of the optical constants for each layer from the near ultraviolet and visible to the mid infrared. Determination of the optical constants of the electrochromic layer cannot be made in isolation; a complete device or at least a half-cell including a layer of ITO is required to change the optical state of the electrochromic material. Measurements on ITO were made using variable-angle spectral ellipsometry, and spectral transmittance and reflectance. A series of structural models were fit to this data. The problem is complicated because of inhomogeneity in the films, variability in the manufacturing process, and sensitivity to environmental conditions. The spectral dependency was modeled by a single Lorentz oscillator and a Drude free-electron component. This data was then used as the basis for a model to extract the optical constants for a tungsten oxide electrochromic film.

1 avon Rottkay, Klaus1 aRubin, Michael, D.1 aÖzer, Nilgün uhttps://facades.lbl.gov/publications/optical-indices-tin-doped-indium