Synthesis, characterization, and dye-sensitized solar cell fabrication using solid biopolymer electrolyte membranes

Abstract

Solid biopolymer-based electrolytes have been synthesized and characterized. Potassium iodide (KI) and iodine have been added in a biopolymer (sago palm) matrix to develop solid polymer electrolyte. Relationships between electrical and ionic transport parameters have been studied in detail, and the mechanism for ion transport has been proposed. Impedance spectroscopy reveals a significant enhancement in ionic conductivity by salt doping and the conductivity maxima was obtained at 50 wt% of KI concentration and also the system displays Arrhenius behavior. Dielectric phenomenon, mobility, charge carrier density, and diffusion coefficient also supports the conductivity data. Fourier transform infrared spectroscopy confirms the formation of a complex structure, while X-ray diffraction and optical microscopy affirms the complex structure as well as a reduction of crystallinity in the biopolymer electrolyte by salt doping. A dye-sensitized solar cell fabricated using fluorine-doped tin oxide–titanium dioxide (N3 dye)/maximum conducting electrolyte showed the short-circuit current density of 2.91 × 10−4 A cm−2, open-circuit voltage of 0.58 V, and efficiency of 0.57% at 1 sun condition.

Perspectives for solid biopolymer electrolytes in dye sensitized solar cell and battery application

“…In our laboratory we have tested a series of biopolymers(like Agarose/ Agars, Sago Starch, Arrowroot Starch, Phythagel)doped with different alkali metal salts and carried out detailed electrical and structural investigations specific for the application area of DSSCs [101,136,137,166]. The experimental observations and discussions are described below.…”

“…In some instances, biopolymer films are soaked in an electrolyte solution to allow diffusion of ions. The BPE film matrix obtained is characterized by using various techniques [101,136,137,166]. The basic organic chemistry and physics that lie behind preparation and working principle of a BPE is summarized in the following section.…”

“…The photovoltaic parameters of polysaccharides with various salts (like NaI, KI and NH 4 I etc) are reported in literature and tabulated in Table 3. As expected, the most efficient biopolymer electrolyte based DSSCs contain I À /I 3 À redox couple [101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116][117]136,137,160,166,[178][179][180][181].…”

“…For developing redox couple in biopolymer-KI electrolyte system, addition of iodine in the polymer matrix is needed.DSSCs arefabricated by using the highest ionic conductivity composition of the electrolytes. The different photovoltaic parameters such as J sc (A cm À 2 ), V oc (V), FF (%), Area (cm 2 ) and light intensity in biopolymers: salt matrix developed in our laboratory [101,136,137,166] as well as exist in literature are listed in Table 7 [101-181].…”

“…It is clear that adding KI in Arrowroot matrix enhances the ionic conductivity and conductivity maxima were obtained by doping NaI and KI concentration where conductivity value approaches at 6.7 Â 10 À 4 and 1.04 Â 10 À 4 S/cm, respectively [166,167]. Adding (GlycerolþLiCl) and KI in Sago Palm matrix enhances the ionic conductivity and conductivity maxima was obtained by adding LiCl where conductivity value approachedto 10 À 3 S/cm with LiCl [38] and 3.4 Â 10 À 4 S/cm for KI [136,137]. Potato starch with NH 4 I based biopolymer electrolyte prepared by solution casting technique gives best ionic conductivity of ∼2.4 Â 10 À 4 S/cm [163].…”