**4.3 Ink-jet printing**

Ink-jet technology for electronic circuit manufacturing at very low costs has been used, and additional applications in this desirable technology have been noted. It is very interesting to create powerful inks for the versatile display of electronic devices using ink-jet technology. Researchers have prepared the AgNPs through chemical reduction from the silver nitrate using triethylamine to reduce and protect agents. The nanoparticles have been sintered through washing it with

**Figure 4.** *SEM image of silver nanorods grown on the Si substrate at (a) 313 K and (b) 133 K [41].*

acetone and deionised water to remove the particles and organic contaminants present on the surface; after cleaning the film, it was treated with ozone by UVO-100 UV ozone for 30 min. These AgNPs suspensions were spin-coated with 500 rpm, 15 seconds on the polyimide substrate and dried at room temperature to remove the solvent. The resulting AgNPs on the polyimide substrate was heated from 100 to 200 °C and held at 200 °C for 1 h to convert to silver films. The synthesised AgNPs were sintered at different temperatures, and it was shown that the resistivity of the silver film sintered at 150 °C for 1 h was close to the resistivity of bulk silver. Upon the results, the prepared nanoparticles showed a low sintering temperature. Therefore, silver nanoparticles would be used to construct the electronics through ink-jet printing [42].

#### **4.4 Fillers**

The micro-sized silver particle fillers are seen as full density silver flakes; they had demonstrated to be highly porous agglomerates. Conjugated polymers with different nanoscale filler inclusions **have been investigated for** sensor applications, including gas sensors, biosensors, and chemical sensors. **Nanofill**ers used include nanowires of metal oxide, nanotubes of **carbon and nanoscale** silver [43]. In the coming decades, nanofiller-based silver nanoparticles and their related products are very promising. In the future, we will face many risks and challenges, in particular energy problems, and research into sustainable energy conversion is expected to explode, both theoretically and experimentally, and polymer nanocomposites will not stand out from this trend, such as self-cleaning or "easyto-clean" coatings, coated on the surface of a building, protective substrates and glass can help to save energy and water in facility cleaning. In contrast, insulating nanocomposite coatings can help save billions of dollars in energy savings to keep homes in winter.

#### *4.4.1 AgNPs as inorganic filler*

Mineral or metallic fillers are reviewed as inorganic fillers. Clay, nano clay [montmorillonite (MMT)], silver nanoparticles (AgNPs), and calcium carbonate (CaCO3) are the most common inorganic reinforcement material-based composites. AgNPs is also a popular metallic filler due to its physicochemical properties, including optical, electrical, catalytic, antimicrobial, and therapeutic properties. It can be synthesised either chemically or biologically. Conventional physical and chemical methods are more costly and toxic than biological methods that can produce nanoparticles in high yields, with good solubility and stability [44]. The biological method is most preferred and very simple, cost-effective, fast, environmentally friendly, and non-toxic. The green approach is preferred for synthesising AgNPs because it uses bacteria, plant extracts, fungi, vitamins, and amino acids far from chemical methods. Few researchers had analysed these nanoparticles via TEM. The resistivity was also evaluated through various levels of filler loading. The AgNPs prepared and synthesised were spheres and nano-sized approximately 50–150 nm in diameter and micro-sized particles with diameters of 5–8 μm, and flakes of silver of 10 μm in length. The data concluded that it was not easy to find the cross-linkage of particles, and there are very lesser chances of different contact and contact area. Through the resistivity measurements, it has been demonstrated that the conductivity of micro-sized silver particle-filled adhesive is influenced by constriction resistance, the AgNPs-containing adhesive is controlled by tunnelling and even thermionic emission. Therefore the particular AgNPs were succeeded to increase the electrical conductivity [45].

**227**

**Figure 5.**

*Silver Nanoparticles in Various New Applications DOI: http://dx.doi.org/10.5772/intechopen.96105*

In recent years, the emerging technology in plasmonic effects in thin-film silicon solar cell is widely studied. It has been a promising application in solar cell fabrication industries due to the nanoscale properties of the silver nanoparticles established in the interface between the metal and dielectric contacts which in turn enhance the light-trapping properties of thin-film silicon solar cells through an increase in absorbance capacity and production of hot electrons that enhance the photocurrents in the solar cell [46]. Silver indium sulphide quantum dots (QD) supported by glutathione (GSH) and polyethylene (PET) as dual-ligands have been synthesised by [47] using an environmentally friendly and reproducible aqueous method. The resulting silver indium sulphide quantum dots present surprisingly long lifespans of 3.69 ls, excellent fluorescent stability and low cytotoxicity, making them the ideal candidate for real-time bioimaging. Thus, they can effectively passivate the surface trap centres and thus reduce non-radiative emissions in **Figure 5**.

Few groups have tried to fabricate nano-enzymatic glucose biosensors by depositing AgNPs using the in-situ chemical reduction method on TiO2 nanotubes, which is synthesised using an anodic oxidation process. Scanning electron microscopy was used to determine the structure, morphology, and mechanical activity of the electrode. It was present both inside and outside of TiO2 nanotubes whose length and diameter were about 1.2 μm and 120 nm. The composition was constructed and used as an electrode of a non-enzymatic biosensor for glucose oxidation. The electrocatalytic properties of the prepared electrodes for glucose oxidation were investigated by cyclic voltammetry (CVs) and differential pulse voltammetry (DPV). Nano enzymatic glucose biosensors have exciting applications in catalysis and sensor areas [48]. In [49] work, their silver nanostructures were significantly stabilised by the Mercaptopropionic Acid (MPA), and Self Assembled Monolayer (SAM) biosensor detection limit for endotoxin *E.coli* was estimated at 340 pg./ml. We investigated biosensor selectivity in different experiments, taking endotoxin *B.abortus* as the second form of endotoxin contamination in our target samples (HBs-ag developed

*Silver indium sulphide QDs stabilised by GSH and PET have been successfully prepared using an* 

*(QY) photoluminescence (PL) of up to 37.2 percent [47].*

*environmentally friendly and reproducible aqueous route. The resulting QDs have an absolute quantum yield* 

**4.5 Solar cell optimisation**

**4.6 Biosensor fabrication**
