electrochromic devices,conducting polymers

1. MAXIMUM CONTRAST FROM ELECTROCHROMIC MATERIALS: LIMITATIONS OF DUAL SYSTEMS Javier Padilla , Venkataramanan Seshadri, Gregory A. Sotzing and Toribio F.Otero Center for Electrochemistry and Intelligent Materials, UPCT, Spain Institute of Materials Science UCONN, USA 234th ACS NATIONAL MEETING 2007, BOSTON AUGUST 19th-23th

2. ELECTROCHROMIC DEVICES: ELECTROCHEMICAL CELLS (WITH INTERESTING APPLICATIONS) + - electrodes Ionic conducting medium ions e -

3. Number of publications related to synthesis and electrochromism (1997-2007): 505 Number of publications about optimization of contrast: 1 !!!! J. Y. Lim, H. C. Ko, H. Lee, Synthetic Metals, 155 (2005) 595. MOTIVATION

4. Observation Absorbance A=-log(I f /I i )=C  d Magnitudes Thickness of the material Molar absortivity of the material Concentratión of absorbent species (directly related to oxidation-reduction) Contrast ~ 0 Contrast ~ 0 Máximum contrast? Quantified by means of the Absorbance= -log(I f /I i ) Transmittance T=10 -A Contrast  T=T c -T d STARTING POINT Lambert-Beer law I i I f Contrast ???

5. LAMBERT-BEER LAW… A=C  d A=  q C  number of absorbent species number of absorbent species  q Absorbent species Photon  q Coloration efficiency Charge per surface unit

6. OBTENTION OF MAXIMUM CONTRAST FOR A SINGLE POLYMER Absorbance-redox charge relation Electrochemical characterization Optical characterization A=  q T = exp(-  q)  =2.303    T = 100[exp(-  c q) - exp(-  d q)] J. Padilla, V. Seshadri, G. A. Sotzing, T. F. Otero, Electrochem. Commun. 2007 , 9 , 1931. ONLY ONE FILM TO OBTAIN ALL THE INFORMATION!!!

7. DUAL SYSTEMS. COMPLEMENTARY POLYMERS + = Cathodic coloration Anodic coloration EXPECTED BENEFITS: LONGER LIFETIME ENHANCED CONTRAST PBEDOT-NMCz PEDOT

8. 25 Combinaciones. Simulación Experimental confirmation Dual combinations: Theoretical prediction Individual characterization OBTENTION OF MAXIMUM CONTRAST FOR DUAL SYSTEMS Absorbance of a dual system=Sum of individual abosorbances

9. Redox charge range 0-5 mCcm -2 10 32 combinations!!! Maximum dual contrast < Maximum individual contrast !!!! System chosen: PEDOT/PBEDOT-NMCz   T = 100[exp-(  c1 q 1 +  c2 q 2 ) - exp-(  d1 q 1 +  d2 q 2 )] OBTENTION OF MAXIMUM CONTRAST FOR DUAL SYSTEMS J. Padilla et al (submitted)

11. THANKS FOR YOUR KIND ATTENTION ONE LAST THING……

12. 234th ACS National Meeting (August 19-23, 2007). Our overall theme is “Biotechnology for Health and Wellness” (BIOHW) Biomimetics, Artificial Muscles & Nano-Bio 2007 Scientists Meet Doctors Cartagena, Spain, Europe, Nov 6-7-8-9, 2007 To the memory of Prof. A. MacDiarmid, he had accepted our invitation as plenary lecturer of the congress and his nomination as Honorary Doctor of the Polytechnic Univ. of Cartagena. Major areas of interest are: Biomimetics, Artificial Muscles (Polymeric or Artificial Muscles for the Failing Heart . (One session for medical applications) Nano-Bio COME AND JOIN US AT THE 4th WORLD CONGRESS ON BIOMIMETIC,ARTIFICIAL MUSCLES AND NANO-BIO http://www.upct.es/~nano-bio/index.htm

14. OPTIMIZATION OF THE PRODUCTION PROCESS Studied polymer PBEDOT-NMCz Process rate Energy consumption Quality of the films J. Padilla, T. F. Otero, Journal of Solid State Electrochemistry 2007 , DOI 10.1007/s10008-007-0346-9

16. a) Two layers of 0.069 and 0.654 absorbance (555 nm) b) Addition of a layer with 0.315 absorbance (555 nm) results in a loss of 36.97 %T in the clear layer, and only 10.72 %T in the dark layer. Loss in transmittance due to an additional absorbent layer is greater for a clear state. c) Evolution of the transmittance in the clear and dark states of PBPMOM-ProDOT films when an additional layer of PBEDOT-NMCz (3.85 mCcm -2 , 0.1983 and 0.5179 absorbance in its clear and dark states, respectively) is included. d) Evolution of the corresponding contrasts (PBPMOM-ProDOT films alone or with the added PBEDOT-NMCz film).