Phase-selective synthesis of bornite nanoparticlesElectronic Supplementary Information (ESI) available: ICDD database PXRD patterns of high bornite [01-073-1667] and digenite [01-073-8624], XPS data, TEM image (50,000×) of high bornite nanoparticles obtained at 180 °C, PXRD patterns of nanoparticles obtained from various 1-dodecanethiol/oleic acid ratios, PXRD patterns of low bornite particles obtained after 6 h, PXRD patterns of nanoparticles obtained with varying Cu:Fe mole ratios, and mass pe

• Main Authors: Wiltrout, Alex M, Freymeyer, Nathaniel J, Machani, Tony, Rossi, Daniel P, Plass, Katherine E
• Format: Journal Article
• Language: English
• Published: 29.11.2011
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c1jm13677a

Nanoparticles of the copper iron sulfide phase bornite (ideally Cu 5 FeS 4 ) have been synthesized phase selectively. Either the low or high bornite phase can be obtained through alteration of reactant ratios or reaction temperature, revealing a phase-selectivity that results from distinct rates of formation. The phase, shape, size, and composition of these novel nanomaterials are characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The light absorption behaviour was investigated using ultra-violet/visible/near-infrared spectroscopy (UV/vis/NIR), revealing direct band gaps that are phase-dependent (low bornite, E g = 0.86 eV and high bornite, E g = 1.25 eV). The band gap exhibited by high bornite nanoparticles lies in the range of optimal solar energy conversion efficiency for a single-junction photovoltaic, making it a potentially useful light absorber consisting of inexpensive, abundant elements. Lastly, the selective formation of bornite nanoparticles, as opposed to the copper sulphides, chalcocite (Cu 2 S) and digenite (Cu 1.80 S), or chalcopyrite (CuFeS 2 ) is demonstrated, suggesting solid solution formation between bornite and digenite nanoparticles. Novel polymorphic bornite nanoparticles, which are potentially useful solar light absorbers consisting of inexpensive, abundant elements, are synthesized phase selectively.