Abstract
We report the synthesis and photovoltaic properties of a new ternary solar absorber – Ag8SnS6 nanocrystals prepared by successive ionic layer adsorption reaction (SILAR) technique. The synthesized Ag8SnS6 nanocrystals have a bandgap Eg of 1.24–1.41 eV as revealed from UV-Vis and external quantum efficiency (EQE) measurements. Its photovoltaic properties were characterized by assembling a liquid-junction Ag8SnS6 sensitized solar cell for the first time. The best cell yielded a Jsc of 9.29 mA cm−2, a Voc of 0.23 V, an FF of 31.3% and a power conversion efficiency (PCE) of 0.64% under 100% incident light illumination using polysulfide electrolyte and Au counter electrode. The efficiency improved to 1.43% at a reduced light intensity of 10% sun. When the polysulfide was replaced by a cobalt electrolyte with a lower redox level, the Voc increased to 0.54 V and PCE increased to 2.29% under 0.1 sun, a respectable efficiency for a new solar material. The EQE spectrum covers the spectral range of 300–1000 nm with a maximum EQE of 77% at λ = 600 nm. The near optimal Eg and the respectable photovoltaic performance suggest that Ag8SnS6 nanocrystals have potential to be an efficient IR solar absorber.
Highlights
Semiconductor nanocrystals are receiving much research attention in the eld of photovoltaics
Semiconductor nanocrystals materials can be prepared by solution-based processing, which has the advantages of ease of fabrication and lowcost over Si based solar cell processing
The structural property of the prepared Ag–Sn–S ternary phase was investigated by studying its X-ray diffraction (XRD) pattern a er annealing at 400 C under nitrogen atmosphere
Summary
Semiconductor nanocrystals are receiving much research attention in the eld of photovoltaics. This is due to the unique properties of semiconductor NC materials such as band gap tenability[1,2] and high absorption coefficient.[3] multiple exciton generation effect and hot electron injection in these solar absorbers could improve the solar cell efficiency beyond the Shockley–Queisser limit.[4,5,6,7,8,9] Semiconductor nanocrystals materials can be prepared by solution-based processing, which has the advantages of ease of fabrication and lowcost over Si based solar cell processing. Liquid-junction quantum dot-sensitized solar cells based on Ag8SnS6 nanocrystals are demonstrated for the rst time. Photovoltaic performance on SILAR conditions, sun intensity and type of electrolyte have been studied
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