Noble metal NPs are highly attractive candidates because of their unique combination of physical, chemical, mechanical, and structural properties. A lot of developments in this area are still fascinating the materials research community, and are broadly categorized in various sectors such as chemical sensors, biosensors, Förster resonance energy transfer (FRET), and microelectronic applications. The related function and properties of the noble metals in these areas can be further tailored by tuning their chemical, optical, and electronic properties that are influenced by their size, shape, and distribution. The most widely used Au and Ag NPs in dispersed phase below 100 nm exhibit strong color change in the visible range which alters upon aggregation of the NPs. The chemical sensing of the analyte is influenced by these NPs aggregates. In this article, we have summarized the uniqueness of noble metal NPs, their synthesis methods, nucleation and growth process, and their important applications in chemical sensing, microelectronic packaging, and Förster resonance energy transfer.

Silver nanorods were synthesized by burning out the as prepared Ag-PVA nanocomposite films at 300 °C in air. Aqueous PVA solution is acts as stabilizing agents for silver nanorods. The formation of silver nanorods was confirmed from the appearance of two surface plasmon absorption maxima at 425 and 465 nm due to transverse and longitudinal mode of vibration of electrons. SEM micrograph showed the resultant nanorods were 500–600 nm in length and 50–70 nm in diameter. It is supported by TEM with more 1000 nm in length and 40–60 nm diameters. The XRD demonstrated that the nanorods were present in fcc crystal of pure silver. Finally the X-ray photoelectron spectroscopy (XPS) also confirmed the formation of silver nanorods with 3d₅/₂ and 3d₃/₂ band at 368.6 and 374.6 eV respectively.

Solar cells based on p-conjugated donor-acceptor (D-A) organic molecular systems are a promising alternative to conventional electrical energy generation. D-A molecular systems, which have a triphenylamine (TPA) moiety linked with a benzothiadiazole (BTD) moiety, open the potential development of new small molecule donors for bulk heterojunction (BHJ) solar cells. Here, a series of donor-acceptor-π-acceptor (D-A-π-A) small molecule donors (SMD) derived from triphenylamine (TPA) donor and benzothiadiazole (BTD) acceptor building blocks, were designed for BHJ organic solar cells. The small molecule donors SMD1-4 were studied using density functional theory (DFT) and time dependent-DFT (TDDFT) methods, to understand the effect of cyano and fluorine group functionalization on their properties. The effect of structure alteration by cyano and fluorine group functionalization on the optoelectronic properties, the calculated highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO gaps were theoretically explored. The V oc (open-circuit photovoltage) and fill factor (FF) for SMD1-4 were obtained with a PC 71 BM acceptor, which showed that these organic small molecules are potential small molecule donors for organic bulk heterojunction solar cells.