%0 Journal Article
%T Green Synthesis of Nanocrystalline Cu2ZnSnS4 Powder Using Hydrothermal Route
%A Shri kant Verma
%A Vikash Agrawal
%A Kiran Jain
%A Renu Pasricha
%A Suresh Chand
%J Journal of Nanoparticles
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/685836
%X Nanocrystalline Cu2ZnSnS4 (CZTS) powder was synthesized by a hydrothermal process, using thiourea as sulfur precursor. The powder was qualitatively analyzed using X-ray to identify the phase, and the size of the particles was determined using transmission electron microscopy (TEM). Raman peak at 337.5£¿cm£¿1 confirms the formation of pure CZTS particles. The powder was also synthesized solvothermally using ethylenediamine as solvent. The hydrothermally synthesized powder indicated the presence of the kesterite phase Cu2ZnSnS4 and particle size of about 4-5£¿nm. This environmentally green synthesis by hydrothermal route can produce gram scale synthesis of material with a chemical yield in excess of ~£¿90%. UV Vis absorption spectra measurements indicated the band gap of as-synthesized CZTS nanoparticles to be 1.7£¿eV, which is near the optimum value for photovoltaic solar cell, showing its possible use in photovoltaics. 1. Introduction Thin film solar cells based on chalcopyrite type semiconductors like CuInSe2, CuInGaSe2 (CIGS), and so forth have shown high efficiency and applicability for large scale applications [1]. CIGS based solar cells exhibit improved stability under long-term excitation, and their best efficiency available nowadays exceeds 20% [2]; however, gallium and indium used for preparation of the active layer are rare earth elements and are expensive also. Hence, Cu2ZnSn(SSe)4 was found of more interest, because of less toxicity, earth abundance, nearly optimum direct band gap of about 1.05¨C1.50£¿eV, and a high absorption coefficient [3, 4]. Compared with the vacuum approaches, the nonvacuum approaches are the more desired techniques to achieve low production costs, because of the advantages offered by these methods, such as simplicity, easy to scale up, and high material utilization [4, 5]. Diverse deposition routes of Cu2ZnSnS4 (CZTS) thin films such as sputtering, spray pyrolysis, sol-gel, and electro-deposition have been reported [6, 7]. Much attention has been focused recently on fabrication of low cost and highly efficient solar cells. In this respect, the synthesis of nanocrystalline powders through wet chemical routes is gaining importance, since spin casting or printing nanocrystalline powders enable roll to roll processing for large scale manufacturing. Solar cells based on Cu2ZnSnSe4 (CZTS) have achieved power conversion efficiencies as high as 11.1% using a hydrazine based approach [8]. However, hydrazine is highly toxic and very unstable, and its use requires extreme caution during handling. Recent advances in the synthesis of
%U http://www.hindawi.com/journals/jnp/2013/685836/