Spectrally Selective PANI/ITO Nanocomposite Electrodes for Dual Band Dynamic Windows
Mirko Magni,a Pelin Yilmaz,b Sandra Martinez,c Rosa Maria Gonzalez Gil,c Monica Della Pirriera,c Michele Mancab,c
a Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Via Golgi 19, Milano, Italy
b IIT- CBN - Fondazione Istituto Italiano di Tecnologia - Center for Biomolecular Nanotechnologies, via Barsanti 14, 73010, Arnesano (Lecce), Italy
c LEITAT Technological Center, Carrer de la Innovaciò 2, 08225, Terrassa (Barcelona), Spain e-mail: [email protected]
Chromogenic materials are able to change their optical properties as a response to an external stimulus, such as light irradiation (photochromic materials), temperature variation (thermochromic materials) or electric potential (electrochromic materials).
Glazing employing electrochromic materials can change their optical characteristics of transparency and absorption of solar radiation according to users’ needs by simultaneously reducing visible light and NIR transmission through the window. However, spectral selectivity has been becoming a key requirement in smart dynamic windows as it permits maximizing both visual and thermal comfort while minimizing energy consumption for heating, cooling, and lighting [1].
Herein, a dual band electrochromic system is presented, which consists of an engineered nanocomposite electrode capable of advantageously combining the broad band plasmonic response of nanocrystalline indium-tin-oxide (ITO) with high optical contrast of polyaniline (PANI). Their synergistical spectroelectrochemical features make possible the implementation of a four-state tunable electrochromic system (here referred to as “plasmochromic”), which permits selectively regulating optical transmittance in the visible and near-infrared range and exhibits excellent spectral selectivity across a potentials window of only 1.2 V, with a visible light vs. solar transmittance ratio tunable from 0.67 to 1.61.
Electrochemical and spectroscopic features of the two constituting components (i.e., ITO nanocrystals and PANI) will be discussed, together with the study of how their single characteristics symbiotically combine each other in defining the performance of the resulting hybrid plasmochromic electrodes.
Finally, a set of dual-band EC devices offering an excellent VIS/NIR spectral selectivity within a relatively small electrochemical window will be presented, discussing their main key features [2].
400 600 800 1000 1200 1400 1600
0 20 40 60 80
Transmission (%)
Wavelength (nm)
OCP -1.3V -1.7V -2.1V -2.3V -2.4V -2.5V -2.6V -2.8V -3.2V +0.3V +0.5V +0.6V +0.7V +1.4V
a
-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0
1 2 3 4 5
Rp
CPE1 CPE2 Rs
Rs Rp Credox
Voltage Applied vs Saturated AgCl/Ag (V) log (R (W cm2))
a
-5 -4 -3 -2
log (C (F cm-2))
1 10 100 1000 10000 100000
0 20 40 60 80
PANI/ITO at -0.25V PANI at -0.25V PANI/ITO at 0.10V PANI at 0.10V PANI/ITO at 0.95V PANI at 0.95V
j (o)
w (rad s-1) a
–
References
[1] F. Pacheco-Torgal, S. Jalali, Constr. & Build. Mater., 25 (2011) 582.
[2] P. Yilmaz, M. Magni, S. Martinez, R.M. Gonzalez Gil, M. Della Pirriera, M. Manca, ACS Appl.
Energy Mater. 3 (2020) 3779.
