-
CLEO Collaboration,
D. M. Asner,
G. Tatishvili,
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
J. Napolitano,
K. M. Ecklund, [......],
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
A. Powell,
C. Thomas,
G. Wilkinson
[show abstract]
[hide abstract]
ABSTRACT: We analyze a sample of 3 million quantum-correlated D0 D0bar pairs from 818
pb^-1 of e+e- collision data collected with the CLEO-c detector at E_cm = 3.77
GeV, to give an updated measurement of \cos\delta and a first determination of
\sin\delta, where \delta is the relative strong phase between doubly
Cabibbo-suppressed D0 --> K+pi- and Cabibbo-favored D0bar --> K+pi- decay
amplitudes. With no inputs from other experiments, we find \cos\delta = 0.81
+0.22+0.07 -0.18-0.05, \sin\delta = -0.01 +- 0.41 +- 0.04, and |\delta| = 10
+28+13 -53-0 degrees. By including external measurements of mixing parameters,
we find alternative values of \cos\delta = 1.15 +0.19+0.00 -0.17-0.08,
\sin\delta = 0.56 +0.32+0.21 -0.31-0.20, and \delta = (18 +11-17) degrees. Our
results can be used to improve the world average uncertainty on the mixing
parameter y by approximately 10%.
10/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: Hybrid electrolytes produced by the sol–gel process were obtained by doping a di-urea cross-linked POE/ siloxane hybrid host framework (d-U(2000)) with lithium hexafluoroantimonate (LiSbF 6). Flexible, transparent xerogel films with ∞ > n ≥ 2.5 (where n, composition, represents the molar ratio of oxyethylene units OCH 2 CH 2 per Li + ion), thermally stable to at least 200 °C, were prepared. At 30 °C the highest ionic conductivity of all the electrolytes prepared was 1.32 × 10 − 5 S cm − 1 for n = 30. The electro-chemical stability windows of these materials span at least 6.0 V. Samples with n b 200 are amorphous, ho-mogeneous and non-porous. Crystallites of POE are formed in the most dilute electrolyte (n = 200). The guest Li + ions were shown to coordinate to the oxygen atoms of the urea carbonyl groups over the entire range of salt concentration. The great majority of the SbF 6 − ions interact with the Li + ions. Contact ion pairs were detected only at n = 200. Trace amounts of "free" anions exist in all electrolyte samples.
-
J. Insler,
H. Muramatsu,
C. S. Park,
L. J. Pearson,
E. H. Thorndike,
S. Ricciardi,
C. Thomas,
M. Artuso,
S. Blusk,
R. Mountain, [......],
G. Wilkinson,
D. M. Asner,
G. Tatishvili,
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
J. Napolitano,
K. M. Ecklund
[show abstract]
[hide abstract]
ABSTRACT: The first measurements of the coherence factor RKS0Kπ and the average strong-phase difference δDKS0Kπ in D0→KS0K∓π± decays are reported. These parameters can be used to improve the determination of the unitary triangle angle γ in B-→D˜K- decays, where D˜ is either a D0 or a D̅ 0 meson decaying to the same final state, and also in studies of charm mixing. The measurements of the coherence factor and strong-phase difference are made using quantum-correlated, fully reconstructed D0D̅ 0 pairs produced in e+e- collisions at the ψ(3770) resonance. The measured values are RKS0Kπ=0.73±0.08 and δDKS0Kπ=(8.3±15.2)° for an unrestricted kinematic region and RK*K=1.00±0.16 and δDK*K=(26.5±15.8)° for a region where the combined KS0π± invariant mass is within 100 MeV/c2 of the K*(892)± mass. These results indicate a significant level of coherence in the decay. In addition, isobar models are presented for the two decays, which show the dominance of the K*(892)± resonance. The branching ratio B(D0→KS0K+π-)/ B(D0→KS0K-π+) is determined to be 0.592±0.044(stat)±0.018(syst), which is more precise than previous measurements.
Phys. Rev. D. 05/2012; 85(9).
-
CLEO Collaboration,
J. Insler,
H. Muramatsu,
C. S. Park,
L. J. Pearson,
E. H. Thorndike,
S. Ricciardi,
C. Thomas,
M. Artuso,
S. Blusk, [......],
G. Wilkinson,
D. M. Asner,
G. Tatishvili,
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
J. Napolitano,
K. M. Ecklund
[show abstract]
[hide abstract]
ABSTRACT: The first measurements of the coherence factor R_{K_S^0K\pi} and the average
strong--phase difference \delta^{K_S^0K\pi} in D^0 \to K_S^0 K^\mp\pi^\pm
decays are reported. These parameters can be used to improve the determination
of the unitary triangle angle \gamma in B^- \rightarrow \widetilde{D}K^-$
decays, where $\widetilde{D}$ is either a D^0 or a D^0-bar meson decaying to
the same final state, and also in studies of charm mixing. The measurements of
the coherence factor and strong-phase difference are made using
quantum-correlated, fully-reconstructed D^0D^0-bar pairs produced in e^+e^-
collisions at the \psi(3770) resonance. The measured values are R_{K_S^0K\pi} =
0.73 \pm 0.08 and \delta^{K_S^0K\pi} = (8.3 \pm 15.2)$^\circ$ for an
unrestricted kinematic region and R_{K*K} = 1.00 \pm 0.16 and \delta^{K*K} =
(26.5 \pm 15.8)$^\circ$ for a region where the combined K_S^0 \pi^\pm invariant
mass is within 100 MeV/c^2 of the K^{*}(892)^\pm mass. These results indicate a
significant level of coherence in the decay. In addition, isobar models are
presented for the two decays, which show the dominance of the K^*(892)^\pm
resonance. The branching ratio {B}(D^0 \rightarrow K_S^0K^+\pi^-)/{B}(D^0
\rightarrow K_S^0K^-\pi^+) is determined to be 0.592 \pm 0.044 (stat.) \pm
0.018 (syst.), which is more precise than previous measurements.
03/2012;
-
M. Artuso,
S. Blusk,
R. Mountain,
T. Skwarnicki,
S. Stone,
L. M. Zhang,
T. Gershon,
G. Bonvicini,
D. Cinabro,
A. Lincoln, [......],
G. S. Adams,
J. Napolitano,
K. M. Ecklund,
J. Insler,
H. Muramatsu,
C. S. Park,
L. J. Pearson,
E. H. Thorndike,
S. Ricciardi,
C. Thomas
[show abstract]
[hide abstract]
ABSTRACT: The first flavor-tagged amplitude analysis of the decay D0 to the
self-conjugate final state K+K-pi+pi- is presented. Data from the CLEO II.V,
CLEO III, and CLEO-c detectors are used, from which around 3000 signal decays
are selected. The three most significant amplitudes, which contribute to the
model that best fits the data, are phirho0, K1(1270)+-K-+, and non-resonant
K+K-pi+pi-. Separate amplitude analyses of D0 and D0-bar candidates indicate no
CP violation among the amplitudes at the level of 5% to 30% depending on the
mode. In addition, the sensitivity to the CP-violating parameter gamma/phi3 of
a sample of 2000 B+ -> D0-tilde(K+K-pi+pi-)K+ decays, where D0-tilde is a D0 or
D0-bar, collected at LHCb or a future flavor facility, is estimated to be (11.3
+/- 0.3) degrees using the favored model.
01/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: In view of the potential technological impact of solid polymer electrolytes (SPEs) in the domain of solid-state electrochemistry, particularly in the production of advanced batteries, sensors and electrochromic and photoelectrochemical devices, the sub-class of SPE materials has attracted considerable interest during the last two decades. Li+-doped ormolyte systems obtained using the sol-gel method have been investigated in the last few years. In this study we have used conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis to characterize an electrolyte system based on a lithium perchlorate (LiClO4)-doped di-urethane cross-linked poly(epsilon-caprolactone)(PCL)/siloxane hybrid matrix. The PCL/siloxane host hybrid matrix represents an attractive alternative, as it is expected to have lower environmental impact than electrolytes currently used in commercial devices. The biocompatible, biodegradable and air-permeable properties of the PCL matrix have led to extensive application of this material in the manufacture of suture cord, artificial skin, re-sorbable prosthetic devices and as a container for drug delivery. The amorphous hybrid materials characterized in this study combine acceptable levels of ionic conductivity (9.58 x 10(-5) and 2.53 x 10(-4) S cm(-1) at 25 and 90 degrees C, respectively) with low environmental impact. The authors of a previous publication, have concluded that organic-inorganic systems based on poly(epsilon-caprolactone) may be used as dual-function electrolyte/adhesive component in prototype solid-state electrochromic devices. This component provides significant advantages in optical performance, cycle lifetime and durability of the electrochromic devices relative to conventional liquid electrolytes. (C) 2011 Elsevier B.V. All rights reserved.
Synthetic Metals 01/2012; 161(23-24):2682-2687. · 1.83 Impact Factor
-
G. S. Adams,
J. Napolitano,
K. M. Ecklund,
J. Insler,
H. Muramatsu,
C. S. Park,
L. J. Pearson,
E. H. Thorndike,
S. Ricciardi,
C. Thomas, [......],
K. K. Seth,
A. Tomaradze,
T. Xiao,
L. Martin,
A. Powell,
G. Wilkinson,
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin
[show abstract]
[hide abstract]
ABSTRACT: Using a data sample of 2.59×107 ψ(2S) decays obtained with the CLEO-c detector, we perform amplitude analyses of the complementary decay chains ψ(2S)→γχc1; χc1→ηπ+π- and ψ(2S)→γχc1; χc1→η′π+π-. We find evidence for an exotic P-wave η′π amplitude, which, if interpreted as a resonance, would have parameters consistent with the π1(1600) state reported in other production mechanisms. We also make the first observation of the decay a0(980)→η′π and measure the ratio of branching fractions B(a0(980)→η′π)/B(a0(980)→ηπ)=0.064±0.014±0.014. The ππ spectrum produced with a recoiling η is compared to that with η′ recoil.
Phys. Rev. D. 12/2011; 84(11).
-
CLEO Collaboration,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
L Martin,
A. Powell,
G Wilkinson,
H. Mendez, [......],
M. Selen,
J. Wiss,
J Libby,
M. Kornicer,
R. E. Mitchell,
C. M. Tarbert,
D. Besson,
T. K. Pedlar,
D. Cronin-Hennessy,
J. Hietala
[show abstract]
[hide abstract]
ABSTRACT: Using the entire CLEO-c psi(3770) to DDbar event sample, corresponding to an
integrated luminosity of 818 pb^-1 and approximately 5.4 x 10^6 DDbar events,
we measure the form factors for the decays D0 to rho- e+ nu_e and D+ to rho0 e+
nu_e for the first time and the branching fractions with improved precision. A
four-dimensional unbinned maximum likelihood fit determines the form factor
ratios to be: V(0)/A_1(0) = 1.48 +- 0.15 +- 0.05 and A_2(0)/A_1(0)= 0.83 +-
0.11 +- 0.04. Assuming CKM unitarity, the known D meson lifetimes and our
measured branching fractions we obtain the form factor normalizations A_1(0),
A_2(0), and V(0). We also present a measurement of the branching fraction for
D^+ to omega e^+ nu_e with improved precision.
12/2011;
-
N. Lowrey,
S. Mehrabyan,
M. Selen,
J. Wiss,
J. Libby,
M. Kornicer,
R. E. Mitchell,
M. R. Shepherd,
C. M. Tarbert,
D. Besson, [......],
V. E. Kuznetsov,
J. R. Patterson,
D. Peterson,
D. Riley,
A. Ryd,
A. J. Sadoff,
X. Shi,
W. M. Sun,
J. Yelton,
P. Rubin
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a Dalitz plot analysis of D0→KS0π0π0 using the CLEO-c data set of 818 pb-1 of e+e- collisions accumulated at √s=3.77 GeV. This corresponds to 3×106 D0D̅ 0 pairs from which we select 1259 tagged candidates with a background of 7.5±0.9 percent. Several models have been explored, all of which include the K*(892), K2*(1430), K*(1680), the f0(980), and the σ(500). We find that the combined π0π0 S-wave contribution to our preferred fit is (28.9±6.3±3.1)% of the total decay rate while D0→K̅ *(892)0π0 contributes (65.6±5.3±2.5)%. Using three tag modes and correcting for quantum correlations we measure the D0→KS0π0π0 branching fraction to be (1.058±0.038±0.073)%.
Phys. Rev. D. 11/2011; 84(9).
-
CLEO Collaboration,
G. S. Adams,
J. Napolitano,
K. M. Ecklund,
J. Insler,
H. Muramatsu,
C. S. Park,
L. J. Pearson,
E. H. Thorndike,
S. Ricciardi, [......],
K. K. Seth,
A. Tomaradze,
T. Xiao,
L. Martin,
A. Powell,
G. Wilkinson,
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin
[show abstract]
[hide abstract]
ABSTRACT: Using a data sample of 2.59 x 10^7 psi(2S) decays obtained with the CLEO-c
detector, we perform amplitude analyses of the complementary decay chains
chi_c1 -> eta pi+ pi- and chi_c1 -> eta' pi+ pi-. We find evidence for a P-wave
eta' pi scattering amplitude, which, if interpreted as a resonance, would have
exotic J^PC = 1^-+ and parameters consistent with the pi_1(1600) state reported
in other production mechanisms. We also make the first observation of the decay
a_0(980) -> eta' pi and measure the ratio of branching fractions B(a_0(980) ->
eta' pi)/B(a_0(980) -> eta pi) = 0.064 +- 0.014 +- 0.014. The pi pi spectrum
produced with a recoiling eta is compared to that with eta' recoil.
09/2011;
-
J. Y. Ge,
D. H. Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
J. Napolitano,
K. M. Ecklund,
J. Insler,
H. Muramatsu,
C. S. Park, [......],
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
L. Martin,
A. Powell,
G. Wilkinson
[show abstract]
[hide abstract]
ABSTRACT: Using e+e- collision data corresponding to 5.88×106Υ(3S) [25.9×106ψ(2S)] decays and acquired by the CLEO III [CLEO-c] detectors operating at the Cornell Electron Storage Ring, we study the single-pion transitions from Υ(3S)[ψ(2S)] to the respective spin-singlet states hb[c]. Utilizing only the momentum of suitably selected transition-π0 candidates, we obtain the upper limit B(Υ(3S)→π0hb)<1.2×10-3 at 90% confidence level, and measure B(ψ(2S)→π0hc)=(9.0±1.5±1.3)×10-4. Signal sensitivities are enhanced by excluding very asymmetric π0→γγ candidates.
Phys. Rev. D. 08/2011; 84(3).
-
T K Pedlar,
D Cronin-Hennessy,
J Hietala,
S Dobbs,
Z Metreveli,
K K Seth,
A Tomaradze,
T Xiao,
L Martin,
A Powell, [......],
N Lowrey,
S Mehrabyan,
M Selen,
J Wiss,
J Libby,
M Kornicer,
R E Mitchell,
M R Shepherd,
C M Tarbert,
D Besson
[show abstract]
[hide abstract]
ABSTRACT: Using 586 pb(-1) of e+ e- collision data at E(c.m.) = 4170 MeV, produced at the Cornell Electron Storage Ring collider and collected with the CLEO-c detector, we observe the process e+ e- → π+ π- h(c)(1P). We measure its cross section to be 15.6±2.3±1.9±3.0 pb, where the third error is due to the external uncertainty on the branching fraction of ψ(2S) → π0 h(c)(1P), which we use for normalization. We also find evidence for e+ e- → ηh(c)(1P) at 4170 MeV at the 3σ level and see hints of a rise in the e+ e- → π+ π- h(c)(1P) cross section at 4260 MeV.
Physical Review Letters 07/2011; 107(4):041803. · 7.37 Impact Factor
-
CLEO Collaboration,
J. Y. Ge,
D H Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
J. Napolitano,
K. M. Ecklund,
J. Insler,
H Muramatsu, [......],
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
L Martin,
A. Powell,
G Wilkinson
[show abstract]
[hide abstract]
ABSTRACT: Using e^+e^- collision data corresponding to 5.88M Y(3S) [25.9M psi(2S)]
decays and acquired by the CLEO III [CLEO-c] detectors operating at CESR, we
study the single-pion transitions from Y(3S) [psi(2S)] to the respective
spin-singlet states h_{b[c]}. Utilizing only the momentum of suitably selected
transition-pi^0 candidates, we obtain the upper limit B(Y(3S) -> pi^0 h_b) <
1.2\times 10^{-3} at 90% confidence level, and measure B(psi(2S) -> pi^0 h_c) =
(9.0+-1.5+-1.3)\times 10^{-4}. Signal sensitivities are enhanced by excluding
very asymmetric pi^0 -> gamma gamma candidates.
06/2011;
-
CLEO Collaboration,
N. Lowrey,
S. Mehrabyan,
M. Selen,
J. Wiss,
J Libby,
M. Kornicer,
R. E. Mitchell,
M. R. Shepherd,
C. M. Tarbert, [......],
V. E. Kuznetsov,
J. R. Patterson,
D Peterson,
D Riley,
A Ryd,
A. J. Sadoff,
X Shi,
W. M. Sun,
J Yelton,
P Rubin
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a Dalitz plot analysis of D^0 to K^0_S pi^0 pi^0
using the CLEO-c data set of 818 inverse pico-barns of e^+ e^- collisions
accumulated at sqrt{s} = 3.77 GeV. This corresponds to three million D^0
D^0-bar pairs from which we select 1,259 tagged candidates with a background of
7.5 +- 0.9 percent. Several models have been explored, all of which include the
K^*(892), K^*_2(1430), K^*(1680), the f_0(980), and the sigma(500). We find
that the combined pi^0 pi^0 S-wave contribution to our preferred fit is (28.9
+- 6.3 +- 3.1)% of the total decay rate while D^0 to K^*(892)^0 pi^0
contributes (65.6 +- 5.3 +- 2.5)%. Using three tag modes and correcting for
quantum correlations we measure the D^0 to K^0_S pi^0 pi^0 branching fraction
to be (1.059 +- 0.038 +- 0.061)%.
06/2011;
-
CLEO Collaboration,
L Martin,
A. Powell,
G Wilkinson,
J. Y. Ge,
D H Miller,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
B. Moziak, [......],
R. E. Mitchell,
D. Besson,
T. K. Pedlar,
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao
[show abstract]
[hide abstract]
ABSTRACT: We present the first search for the decay $D^+_{s}\to \omega e^{+}\nu$ to
test the four-quark content of the $D^+_{s}$ and the $\omega$-$\phi$ mixing
model for this decay. We use 586 $\mathrm{pb}^{-1}$ of $e^{+}e^{-}$ collision
data collected at a center-of-mass energy of 4170 MeV. We find no evidence of a
signal, and set an upper limit on the branching fraction of
$\mathcal{B}(D^+_{s}\to\omega e^+\nu)<$0.20% at the 90% confidence level.
05/2011;
-
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
L Martin,
A. Powell,
G Wilkinson, [......],
S. Mehrabyan,
M. Selen,
J. Wiss,
J Libby,
M. Kornicer,
R. E. Mitchell,
M. R. Shepherd,
C. M. Tarbert,
D. Besson,
T. K. Pedlar
[show abstract]
[hide abstract]
ABSTRACT: Using 586 $\textrm{pb}^{-1}$ of $e^{+}e^{-}$ collision data acquired at
$\sqrt{s}=4.170$ GeV with the CLEO-c detector at the Cornell Electron Storage
Ring, we report the first observation of $D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}$
with a significance of $5.3 \sigma$. The ratio of branching fractions
$\calB(D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}) / \calB(D_{s}^{*+} \to D_{s}^{+}
\gamma)$ is measured to be $[ 0.72^{+0.15}_{-0.13} (\textrm{stat}) \pm 0.10
(\textrm{syst})]%$, which is consistent with theoretical expectations.
04/2011;
-
CLEO Collaboration,
T. K. Pedlar,
D. Cronin-Hennessy,
J. Hietala,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
T. Xiao,
L Martin, [......],
N. Lowrey,
S. Mehrabyan,
M. Selen,
J. Wiss,
J Libby,
M. Kornicer,
R. E. Mitchell,
M. R. Shepherd,
C. M. Tarbert,
D. Besson
[show abstract]
[hide abstract]
ABSTRACT: Using 586pb^-1 of e^+e^- collision data at E_CM = 4170MeV, produced at the
CESR collider and collected with the CLEO-c detector, we observe the process
e^+e^- --> pi^+ pi^- h_c(1P). We measure its cross section to be
15.6+-2.3+-1.9+-3.0pb, where the third error is due to the external uncertainty
on the branching fraction of psi(2S) --> pi^0 h_c(1P), which we use for
normalization. We also find evidence for e^+e^- --> eta h_c(1P) at 4170MeV at
the 3sigma level, and see hints of a rise in the e^+e^- --> pi^+ pi^- h_c(1P)
cross section at 4260MeV.
04/2011;
-
D. Besson,
D. P. Hogan,
T. K. Pedlar,
D. Cronin-Hennessy,
J. Hietala,
P. Zweber,
S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze, [......],
J. Yelton,
P. Rubin,
N. Lowrey,
S. Mehrabyan,
M. Selen,
J. Wiss,
J. Libby,
M. Kornicer,
R. E. Mitchell,
C. M. Tarbert
[show abstract]
[hide abstract]
ABSTRACT: We report on a study of exclusive radiative decays of the Υ(1S) resonance into a final state consisting of a photon and two KS0 candidates. We find evidence for a signal for Υ(1S)→γf2′(1525); f2′(1525)→γKS0KS0, at a rate B(Υ(1S)→γf2′(1525))=(4.0±1.3±0.6)×10-5, consistent with previous observations of Υ(1S)→γf2′(1525); f2′(1525)→K+K-, and isospin. Combining this branching fraction with existing branching fraction measurements of Υ(1S)→γf2′(1525) and J/ψ→γf2′(1525), we obtain the ratio of branching fractions: B(Υ(1S)→γf2′(1525))/B(J/ψ→γf2′(1525))=0.09±0.02, approximately consistent with expectations based on soft-collinear effective theory.
Phys. Rev. D. 02/2011; 83(3).
-
[show abstract]
[hide abstract]
ABSTRACT: In this exploratory study the results of characterisation of a poly(oxyethylene) (PEO)/siloxane hybrid network electrolyte doped with lithium hexafluoroarsenate (LiAsF6) are described. In accordance with convention, the lithium salt concentration is expressed in terms of the number of oxyethylene units in the organic component of the host network per Li+ ion guest species. Samples of solvent-free electrolytes were prepared with a range of guest salt concentration using the sol-gel process. Hybrid materials based on LiAsF6, were obtained as mechanically robust, flexible, transparent and completely amorphous films and characterised by conductivity measurements, thermal analysis and electrochemical stability. Preliminary characterisation of electrochromic devices (ECDs) incorporating optimised LiAsF6-doped di-ureasil compositions has confirmed that these electrolytes perform satisfactorily as multifunctional component layers in this application. (C) 2011 Elsevier Ltd. All rights reserved.
Electrochimica Acta. 01/2011; 57:52-57.
-
[show abstract]
[hide abstract]
ABSTRACT: The sol-gel process has been used to prepare hybrid electrolytes composed of a poly(oxyethylene) (POE)/siloxane hybrid network doped with lithium tetrafluoroborate (LiBF4) with compositions of n between infinity and 2.5. In this context the lithium salt concentration has been expressed in terms of the number of oxyethylene units in the organic component of the network per Li+ ion. Electrolyte samples with n >= 20 are thermally stable up to approximately 250 degrees C. All the materials synthesized are semi-crystalline: in the composition range n >= 15 free crystalline POE exists and at 60 >= n >= 2.5 evidence of the presence of a crystalline POE/LiBF4 compound has been found. At n = 2.5 the latter crystalline phase coexists with free salt. The room temperature conductivity maximum of this electrolyte system is located at n = 10 (1.5x10(-5) S cm(-1) at 22 degrees C). The electrochemical stability domain of the sample with n = 15 spans about 5.5 V versus Li/Li+. This new series of materials represents a promising alternative to the LiTFSI- and LiClO4-doped POE and POE/siloxane analogues. Preliminary tests performed with a prototype electrochromic device (ECD) comprising the sample with n = 8 as electrolyte and WO3 as cathodically coloring layer are extremely encouraging. The device exhibits switching time around 50 s, an optical density change of 0.13, open circuit memory of about 4 months and high coloration efficiency (106 cm(2) C-1 in the 3(rd) cycle).
International journal of electrochemical science 01/2011; 6(8):3355-3374. · 3.73 Impact Factor
