Band gap tunable Sn-doped PbSe nanocrystals: solvothermal synthesis and first-principles calculations

Abstract

We have reported that the Sn-doped PbSe nanocrystals could be synthesized via a facile solution-based method. Structural and optical characterizations were employed to investigate the properties of the nanocrystals. The x value could be altered across the entire range from 0.58 to 1 by modulating the ratio of cation precursor contents. The band gap energy of the Sn-doped PbSe nanocrystals could be tuned and changed in a nearly linearly way with respect to the x value. Furthermore, using oleylamine as the solvent promoted the nanocrystals to self-assemble as nano-flowers. The theoretical analysis based on first-principles calculations and density of states (DOS) in the VASP code demonstrates the validity of the experimentally obtained band gap variation and values. The band gap energy values at the edge of the solar spectrum render them as competitive candidates for solar applications.