AgInS 2 nanostructures: sonochemical synthesis, characterization, and its solar cell application S. Mostafa Hosseinpour-Mashkani 1 • Ali Sadeghinia 2 • Zabihullah Zarghami 1 • Kourosh Motevalli 3 Received: 17 April 2015 / Accepted: 7 September 2015 Ó Springer Science+Business Media New York 2015 Abstract According to literature, coordination com- pounds as suitable precursors have never been used for ultrasonic synthesis of AgInS 2 nanostructure. For this purpose, silver(I) salicylate, [Ag(HSal)], as a novel pre- cursor is introduced to synthesize AgInS 2 nanostructure. Besides, the effects of various experimental including reaction time, irradiation power, silver precursors, sulfide sources, surfactant, and type of solvent on morphology, particle size, and chemical structure of the products were studied by SEM and XRD techniques. In order to examine the application of AgInS 2 nanostructures as an absorption layer in FTO/AgInS 2 /CdS/Pt-FTO solar cell, a thin film of CdS was put on an AgInS 2 film through chemical bath in order to build a solar cell. The studies showed that mor- phology and size play crucial role on efficiencyand the highest efficiency (0.12 %) is achieved by flower-like nanostructures while the lowest efficiency (0.045 %) is achieved by agglomerated products. 1 Introduction Semiconductor nanocrystals (NCs) have attracted great attention on their synthesis and characterization because of the unique size and shape dependent properties and could be widely used in light emitting diodes, lasers, solar cells and bio-labeling, etc. [1–4]. I–III–VI (AgMX 2 , CuMX 2 ; M = Al, Ga, In; X = S, Se) ternary compounds containing no highly toxic elements are direct band gap semiconduc- tors with a large absorption coefficient and could be potentially applied in optical devices and photovoltaic solar cells [5–7]. Several methods have been reported for the synthesis of I–III–VI ternary compounds, such as Micro- wave-assisted synthesis [8, 9],ultrasonic spray pyrolysis [10], hydrothermal and solvothermal reactions [11–14], microwave hydrothermal [15, 16], single-source precursor route [17], and hot injection [18, 19]. As one of the most important ternary chalcogenides, AgInS 2 (AIS) is an intriguing functional material because of its promising applications in photovoltaic, optoelectronic and photocat- alytic fields [17, 20]. AgInS 2 can be crystallized in two different phases known as tetragonal (chalcopyrite) and orthorhombic structures. It has found that the orthorhombic phase of AIS has a steady state at above 620 °C, while the chalcopyrite phase is stable below this temperature [9, 20]. Chalcopyrite and orthorhombic phases have the direct band gap energy in the range of 1.86–2.04 eV [9, 20–22]. Mentioned band gap energy values for each of the phases are more than the optimal energy for absorber material (1.45 eV) in solar cell. Therefore, AgInS 2 can be nomi- nated as an appropriate absorber in the shorter wavelength to apply in the solar cell films [20–22]. Although AgInS 2 compound indicates the n-type electrical conductivity but this characteristic can be changed to p-type conductivity via doping with the different elements such as Sb [23] and Sn [24]. In this work, a facile ultrasonic process is intro- duced to fabricate AgInS 2 nanoparticles by using [Ag (HSal)] and AgNO 3 as silver precursors. Besides, InCl 3 Á4H 2 O, and thioglycolic (TGA) acid and thioac- etamide (TAA) were used as indium and sulfur sources, & S. Mostafa Hosseinpour-Mashkani Hosseinpour.sm@gmail.com 1 Young Researchers and Elites Club, Arak Branch, Islamic Azad University, Arak, Iran 2 Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran 3 Applied Chemistry Department, Islamic Azad University, South Tehran Branch, Tehran, Iran 123 J Mater Sci: Mater Electron DOI 10.1007/s10854-015-3763-z