Premium
Development and Properties of Surfactant‐Free Water‐Dispersible Cu 2 ZnSnS 4 Nanocrystals: A Material for Low‐Cost Photovoltaics
Author(s) -
Kush Priya,
Ujjain Sanjeev Kumar,
Mehra Navin Chand,
Jha Pika,
Sharma Raj Kishore,
Deka Sasanka
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201300290
Subject(s) - czts , kesterite , analytical chemistry (journal) , raman spectroscopy , materials science , x ray photoelectron spectroscopy , band gap , absorption spectroscopy , absorption (acoustics) , chemistry , chemical engineering , optoelectronics , optics , physics , chromatography , composite material , engineering
A simple, yet novel hydrothermal method has been developed to synthesize surfactant‐free Cu 2 ZnSnS 4 nanocrystal ink in water. The environmentally friendly, 2–4 nm ultrafine particles are stable in water for several weeks. Detailed X‐ray diffraction (XRD) and high‐resolution transmission electron microscopy revealed the formation of single‐crystalline‐kesterite‐phase Cu 2 ZnSnS 4 . Elemental mapping by scanning electron microscopy/energy dispersive spectrometry corroborated the presence of all four elements in a stoichiometric ratio with minor sulfur deficiency. Finally, Raman spectroscopy ruled out the possible presence of impurities of ZnS, Cu 2 SnS 3 , SnS, SnS 2 , Cu 2− x S, or Sn 2 S 3 , which often interfere with the XRD and optical spectra of Cu 2 ZnSnS 4 . X‐ray photoelectron spectroscopic studies of the as‐synthesized samples confirmed that the oxidation states of the four elements match those of the bulk sample. Optical absorption analyses of thin film and solution samples showed high absorption efficiency (>10 4 cm −1 ) across the visible and near‐infrared spectral regions and a band gap E g of 1.75 eV for the as‐synthesized sample. A non‐ohmic asymmetric rectifying response was observed in the I – V measurement at room temperature. The nonlinearity was more pronounced for this p‐type semiconductor when the resistance was measured against temperature in the range 180–400 K, which was detected in the hot‐point probe measurement.