Supplementary Information for:
Wurtzite Cu2ZnSnSe4 nanocrystals for high
performance organic-inorganic hybrid photodetectors
Jian-Jun Wang, Jin-Song Hu, Yu-Guo Guo,* and Li-Jun Wan*
Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National
Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of
Sciences (CAS), Beijing 100190, P.R. China
*E-mail: ygguo@iccas.ac.cn; wanlijun@iccas.ac.cn
Experimental Section
Synthesis of Oleate compounds. The Cu–oleate complex was prepared by reacting CuCl2 and sodium
oleate. In a typical synthesis of Cu–oleate complex, CuCl2∙2H2O (40 mmol) and sodium oleate (80mmol)
was dissolved in a mixture solvent composed of 80 ml ethanol, 60 ml distilled water and 140 ml hexane.
The resulting solution was heated to 70 °C and kept at that temperature for four hours. When the
reaction was completed, the upper organic layer containing the Cu–oleate complex was washed three
times with 30 ml distilled water in a separatory funnel. After washing, hexane was evaporated off,
resulting in Cu–oleate complex in a waxy solid form. The Zn-oleate and In-oleate were prepared
similarly.1
(1)
Park, J.; An, K.; Hwang, Y.; Park, J.; Noh, H.; Kim, J.; Park, J.; Hwang, N.; Hyeon, T. Ultralarge-scale syntheses of monodisperse nanocrystals. Nature Mater. 3, 891-895 (2004).
Figure S1. TEM image of as-synthesized CZTSe NCs in different solvents (a) oleylamine. (b) 2 ml oleic
acid and 6 ml hexadecane.
Figure S2. XRD patterns of synthesized CZTSe NCs by using diphenyl diselenide at a heating rate of 4
oC/min. (b) a corresponding TEM image.
Figure S3. XRD patterns of synthesized CuInSe2 NCs by using Cu–oleate and In–oleate (a) by using
diphenyl diselenide and different solvent 1) oleylamine. 2) 2 ml oleic acid and 6 ml hexadecane. (b) by
using oleylamine and different Se sources. 1) diphenyl diselenide. 2) selenourea. 3) Se powder.
Figure S4. (a) A low-magnification TEM image of CZTSe NCs synthesized by injecting Se source, (b)
XRD patterns of synthesized CZTSe NCs by hot injection.
Figure S5. High-resolution XPS spectrum of Cu 2p (blue), Zn 2p (green), Sn 3d (orange), and Se 3d
(black). The copper HR-XPS spectrum shows two symmetric peaks at 931.5 and 951.3 eV with a peak
splitting of 19.8 eV, characteristic of monovalent copper. The zinc 2p peaks located at 1021.3 and
1044.2 eV show a peak separation of 22.9 eV, consistent with the standard splitting of 22.97 eV,
suggesting Zn (II). The tin 3d peaks located at 485.8 and 494.3 eV, and a peak splitting of 8.5 eV
indicates Sn (IV). The Se 3d peak located at 53.9 eV indicating Se2-.
Figure S6. Energy dispersive X-ray spectroscopy (EDS) of the synthesized wurtzite structure CZTSe.
The C, O and Ni peaks come from the Ni grid.
Figure S7. UV-vis absorption spectrum of wz-CZTSe NCs. The inset shows an obtained band gap of
1.46 eV.
Figure S8. Typical SEM images of (a) P3HT:CZTSe hybrid film and (b) CZTSe NCs.