HOPV12 - Blogs

4 th Hybrid and Organic Photovoltaic Conference -Uppsala 2012 308
C160 -Dynamical modulation of the optical transmittance in multifunctional dyesensitized
photelectrochemical devices based on the implementation of indium-tin
oxide plasmonic resonators
Michele Manca *a , Francesco Todisco b , Roberto Giannuzzi a , Alessandro Cannavale a , Raffaella
Buonsanti c , Luisa De Marco a , Delia Milliron c , Giuseppe Gigli a
a, Italian Institute of Technology, via Barsanti 1 , Arnesano (LECCE), 73010, IT
b, Dipartimento Interateneo di Fisica , Via Amendola 173 - 70125 BARI , IT
c, The Molecular Foundry - Lawrence Berkeley National Laboratory , Berkeley (CA) 94720 , USA
A photovoltachromic cell 1 may potentially act as a complex artificial skin, by generating
electric energy as a photovoltaic system but also ‘‘perceiving’’ even small variations in external
radiation and controlling the energy fluxes by means of a smart variation of their optical
transmittance. To this aim we recently developed a specifically designed bi-functional
counterelectrode by depositing a C-shaped platinum frame which bounds a square region
occupied by a tungsten oxide (WO3) film, onto a transparent conductive substrate. 2 These two
regions have been electrically separated to make possible distinct operations on one or both of
the available circuits. This allowed to measure two different sets of parameters: those
corresponding to the photovoltaic functionality (PV circuit) and those corresponding to the
photoelectrochromic one (PEC circuit). Such an unconventional counterelectrode makes it
possible to achieve a twofold outcome: a smart and fast-responsive control of the optical
transmittance and a relatively high photovoltaic conversion efficiency.
At the same time, in the recent literature transparent conductive oxide (TCO) nanocrystals
(NCs) have been demonstrated to act as plasmonic electrochromic materials able to selectively
modulate the infrared region. 3 Unlike metals, plasmon resonance frequencies of doped
semiconductors can be modified by changing the material’s composition, creating new
opportunities for plasmonic manipulation of light. In fact, a well-defined localized surface
plasmon resonance have recently been observed in the optical (infrared) spectra of highly
doped semiconductor nanocrystals, especially transparent conducting oxides such as indiumtin
oxide (ITO) 4
Figure 1 Schematic representation of the photovoltachromic cells realized for the present study. 1.Electric
separation on the counterelectrode; 2. Platinum catalyzer; 3. Dynamically switchable electrode; 4. TCO; 5. Glass
substrate; 6. Sealant; 7. Titanium dioxide and dye absorbed; Circuitry: Red: photovoltaic; Blue:
Photoelectrochromic.
Starting from these remarks, we recently implemented the above referred TCO NCs a
switchable plasmonic resonators in the photoelectrochromic (PE) half of a PVCC making them
possible to generate an effective dynamic (and reversible) modulation of the optical
adsorption. 5 To do this we advantageously combined the optical switchability in the NIR region
of a TCO-NCs-based mesoporous film with the photovoltaic functionality of dye-sensitized
solar cell, thus defining a rout for the development of a novel class of photoelectrochromic
© SEFIN 2012