Effect of Sn concentration on optical and structural properties of Pb1-xSnxS nanopowder Rahim Lotfi Orimi, Hasan Khandan Fadafan and Alameh Asadpour Eur. Phys. J. Appl. Phys., 67 2 (2014) 20404 Published online: 08 August 2014 DOI: 10.1051/epjap/2014140159