Metallic nanoparticles (NPs) are of great importance owing to their unique distinctiveness and potential requests in numerous applications. Recently, silver (Ag) NPs, due to their unique and extraordinary properties, has been of interest to a large number of researchers. Overall, there are three essential approaches for manufacturing NPs, namely; chemical, physical and biological or green approaches. In the present study, Ag NPs have been synthesized using Citrullus colocynthis fruit extract and a eutectic-based ionic liquid, as a reducing, capping and stabilizing agent. Additionally, these mediums are one-pot, environmentally friendly and economic for synthesizing pure, stable, highly crystalline, thermally stable NPs. Then the biosynthesized Ag NPs were identified by means of diverse description methods to investigate their size, purity, stability, degree of crystallinity, structure, thermal and optical properties. Afterward, the biosynthesized Ag NPs, from both mediums, has been utilized for thin film preparation using the spin-coating method. The p-type silicon (100) wafer utilized as a substrate and the Ag NPs disseminated on the substrate homogeneously. The utilized characterization showed that the synthesized Ag NPs thin film possesses highly standard properties of thin film in which can be utilized for photovoltaic devices.

Silver nanoparticles (Ag NPs) can be produced from various approaches including physical, chemical, and biological approaches. However, green synthesis methods are simple, efficient, and eco-friendly methods and provide relatively more stable nanoparticles. In the current investigation, Ag NPs have been synthesized utilizing Citrullus colocynthis fruit extract as a reducing, capping, and stabilizing agent. Then, Ag NPs were characterized through various classification methods to investigate their size, purity, stability, degree of crystallinity, structure, and optical properties. The impact of different parameters including concentration of AgNO 3 , pH, and reaction temperature on the biosynthesized Ag NPs and corresponding surface plasmon resonance (SPR) behavior were investigated intensively. This study showed that increasing pH values cause tightening the SPR peaks, and therefore, obtaining monodisperse NPs. On the other hand, increasing the reaction temperature increased the band gap of NPs and, thus, reduced the size of NPs. However, the agglomeration state and later the stability of the biosynthesized Ag NPs are increasing with increasing the AgNO 3 concentration. This investigation, exceptional and unique, confirms that reaction pH, the reaction temperature, and the precursor concentration play important roles in the formation process of NPs. Through selective combination of these trio, one can produce Ag NPs with desired structural, morphological, and optical properties which can be suitable for different applications. Keywords Green synthesis method; Silver nanoparticles; Reaction pH; Citrullus colocynthis fruit extract737 4.0). You are free to copy and redistribute articles in any medium 738 or format and also free to remix, transform, and build upon articles 739 for any purpose (including a commercial use) as long as you give 740 appropriate credit to the original source and provide a link to the 741 Creative Commons (CC) license. If you modify the material, you 742 must indicate changes in a proper way.743