Page 560 - Polymer-based Nanocomposites for Energy and Environmental Applications

Hybrid materials based on polymer nanocomposites for environmental applications 513

more abundant and cheaper than platinum (Pt) electrode used in conventional type
DSSCs. 0.1 wt% CoS nanoparticles were dispersed in aqueous PEDOT/PSS solution
and sonicated [28]. Furthermore, the mixture was kept under stirring for 12 h to
achieve good dispersion. The PEDOT/PSS/CoS nanocomposite films were prepared
by spin-coating process from the above dispersed solution. Titanium carbide (TiC) is a
conductive ceramic material with high hardness and electrochemically inert nature.

Besides, it shows some catalytic activity toward I 3 reduction. TiC/PEDOT/PSS com-
posite films have been studied and used as counter electrodes for DSSCs [29]. Com-
mercial PEDOT/PSS aqueous solution containing 10 wt% TiC nanoparticles was cast
into thin film by the doctor-blade method. Silicon (Si) crystals, including single- and
multicrystalline types, have dominated photovoltaic industry for decades. Si has sev-
eral advantages for mass production such as its abundance on Earth, nontoxicity, high-
thermal stability, and strong light absorption. It is reported that exciton dissociation at
the polymer/Si interface is energetically favored and becomes increasingly favorable
for quantum-confined Si nanocrystals [30]. P3HT and Si nanocrystals were mixed in
dichlorobenzene, sonicated for a certain time, and spincast into nanocomposite film to
serve as the active layer in hybrid solar cells.
Single-walled CNTs (SWCNTs) and multiwalled CNTs (MWCNTs) have been
intensively studied due to the unique quasione-dimensional nanostructure and out-
standing electronic properties. The investigations of CNTs have been focused not only
on fundamental issues but also on miscellaneous industrial applications such as tran-
sistors, supercapacitors, light-emitting devices, and solar cells. It has been reported
that 0.1–0.2 wt% SWCNTs relative to PVK were mixed together in toluene and ultra-
sonicated, followed by spin-coating process to form nanocomposite layers, serving as
the hole transport layer (HTL) to improve device efficiency of organic light-emitting
diodes (OLEDs) [31]. SWCNTs and poly(3-octylthiophene) (P3OT) were dissolved in
chloroform separately. The desired composite was prepared by mixing the two sep-
arate solutions, and uniformity of the mixed solution was attained through sonication.
The SWCNTs/P3OT nanocomposite layers were obtained by either spin-coating,
drop-casting, or printing techniques [32]. SWCNTs and P3HT were mixed in chloro-
benzene and sonicated for better dispersion, followed by spincoating to give
SWCNTs/P3HT nanocomposite films [33]. SWCNTs and a luminescent polymer
MEH-PPV were mixed in chlorobenzene and sonicated, followed by spincoating to
obtain nanocomposite layer for OLED application [34]. COOH-functionalized
SWCNTs were added in aqueous PEDOT/PSS solution and placed in an ultrasonic
bath for a few hours to reach better dispersion.
The SWCNT/PEDOT/PSS nanocomposite films were prepared by spin-coating
method [35]. Turning to MWCNTs, it is found that 1%–1.35% MWCNTs could be
dispersed well in aqueous PEDOT/PSS or poly(styrenesulfonic acid) solution under
ultrasonication [36]. The composite film was obtained by spin-coating process from
the composite solution, and the thickness of the composite film was controlled by
adjusting the spin rate. 0.625 wt% acid-functionalized MWCNTs in aqueous
PEDOT/PSS solution incorporating small amounts of surfactant (sorbitol or sodium
dodecyl sulfate) were prepared and sonicated to ensure a homogeneous mixture,
followed by spincoating or inkjet printing to deposit into nanocomposite films [37].