Lead tin sulfide (Pb1-xSnxS) nanocrystals: A potential solar absorber material

Yen-Chen Zeng; Sheng-Fong Sie; Nipapon Suriyawong; Belete Asefa Aragaw; Jen-Bin Shi; Ming-Way Lee

doi:10.1016/j.jcis.2016.11.005

Lead tin sulfide (Pb_1-_xSn_xS) nanocrystals: A potential solar absorber material

J Colloid Interface Sci. 2017 Feb 15:488:246-250. doi: 10.1016/j.jcis.2016.11.005. Epub 2016 Nov 2.

Authors

Yen-Chen Zeng¹, Sheng-Fong Sie¹, Nipapon Suriyawong¹, Belete Asefa Aragaw¹, Jen-Bin Shi², Ming-Way Lee³

Affiliations

¹ Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.
² Department of Electronic Engineering, Feng Chia University, Taichung 40724, Taiwan.
³ Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan. Electronic address: mwl@phys.nchu.edu.tw.

PMID: 27835818
DOI: 10.1016/j.jcis.2016.11.005

Abstract

We present a new ternary semiconductor absorber material - Pb_1-_xSn_xS - for solar cells. Pb_1-_xSn_xS nanocrystals (NCs) were synthesized using the successive ionic layer adsorption reaction (SILAR) process. Energy-dispersive X-ray spectroscopy revealed the Sn ratio for a sample prepared with five SILAR cycles to be x=0.55 (i.e. non-stoichiometric formula Pb_0.45Sn_0.55S). The optical spectra revealed that the energy gap E_g of the Pb_1-_xSn_xS NCs decreased with an increasing number of SILAR cycles n, with E_g=1.67eV for the sample with n=5. Liquid-junction Pb_1-_xSn_xS quantum dot-sensitized solar cells were fabricated using the polysulfide electrolyte. The best cell yielded a short-circuit current density J_sc of 10.1mA/cm², an open circuit voltage of 0.43V, a fill factor FF of 50% and an efficiency of 2.17% under 1 sun. The external quantum efficiency spectrum (EQE) covered a spectral range of 300-800nm with a maximum EQE of ∼67% at λ=650nm. At the reduced light of 0.1 sun, the efficiency increased to 3.31% (with a normalized J_sc=17.7mA/cm²) - a respectable efficiency for a new sensitizer. This work demonstrates that Pb_1-_xSn_xS shows potential as a solar cell absorber.

Keywords: Lead tin sulfide; Liquid junction; Quantum dot; Solar cell; Successive ionic layer adsorption and reaction.