Near-Infrared Absorbing Cu12Sb4S13 and Cu3SbS4 Nanocrystals: Synthesis, Characterization, and Photoelectrochemistry

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• 作者：Joel van Embden ; Kay Latham ; Noel W. Duffy ; Yasuhiro Tachibana
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：August 7, 2013
• 年：2013
• 卷：135
• 期：31
• 页码：11562-11571
• 全文大小：553K
• 年卷期：v.135,no.31(August 7, 2013)
• ISSN：1520-5126

文摘

Herein, we present the novel synthesis of tetrahedrite copper antimony sulfide (CAS) nanocrystals (Cu₁₂Sb₄S₁₃), which display strong absorptions in the visible and NIR. Through ligand tuning, the size of the Cu₁₂Sb₄S₁₃ NCs may be increased from 6 to 18 nm. Phase purity is achieved through optimizing the ligand chemistry and maximizing the reactivity of the antimony precursor. We provide a detailed investigation of the optical and photoelectrical properties of both tetrahedrite (Cu₁₂Sb₄S₁₃) and famatinite (Cu₃SbS₄) NCs. These NCs were found to have very high absorption coefficients reaching 10⁵ cm^鈥? and band gaps of 1.7 and 1 eV for tetrahedrite and famatinite NCs, respectively. Ultraviolet photoelectron spectroscopy was employed to determine the band positions. In each case, the Fermi energies reside close to the valence band, indicative of a p-type semiconductor. Annealing of tetrahedrite CAS NC films in sulfur vapor at 350 掳C was found to result in pure famatinite NC films, opening the possibility to tune the crystal structure within thin films of these NCs. Photoelectrochemistry of hydrazine free unannealed films displays a strong p-type photoresponse, with up to 0.1 mA/cm² measured under mild illumination. Collectively these optical properties make CAS NCs an excellent new candidate for both thin film and hybrid solar cells and as strong NIR absorbers in general.