Lead tin sulfide (Pb1-xSnxS) nanocrystals: A potential solar absorber material.
We present a new ternary semiconductor absorber material - Pb1-xSnxS - for solar cells. Pb1-xSnxS 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 Pb0.45Sn0.55S). The optical spectra revealed that the energy gap Egof the Pb1-xSnxS NCs decreased with an increasing number of SILAR cycles n, with Eg=1.67eV for the sample with n=5. Liquid-junction Pb1-xSnxS quantum dot-sensitized solar cells were fabricated using the polysulfide electrolyte. The best cell yielded a short-circuit current density Jscof 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 Jsc=17.7mA/cm2) - a respectable efficiency for a new sensitizer. This work demonstrates that Pb1-xSnxS shows potential as a solar cell absorber.
Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.
Yen-Chen
YC
Zeng
Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.
Sheng-Fong
SF
Sie
Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.
Nipapon
N
Suriyawong
Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.
Belete Asefa
BA
Aragaw
Department of Electronic Engineering, Feng Chia University, Taichung 40724, Taiwan.
Jen-Bin
JB
Shi
Institute of Nanoscience and Department of Physics, National Chung Hsing University, Taichung 402, Taiwan. Electronic address: mwl@phys.nchu.edu.tw.
Ming-Way
MW
Lee
Lead tin sulfide; Liquid junction; Quantum dot; Solar cell; Successive ionic layer adsorption and reaction