Gas-phase synthesis of nanoparticles of group 12 chalcogenides

Abstract

The effect of pyridine addition upon the gas-phase reactions of hydrogen sulfide (H₂S) or hydrogen selenide (H₂Se) with either dimethylcadmium (Me₂Cd) or dimethylzinc (Me₂Zn) has been investigated. The deposits of CdS, CdSe, ZnSe or ZnS which form have been analysed by powder X-ray diffraction (PXRD), elemental analysis and transmission electron microscopy (TEM). At ambient temperatures the deposits consist of particles in the nanocrystalline size range of the hexagonal phase. The average particle size within the deposits is dependent upon the concentration of pyridine in the gas phase, the temperature at which the reactants are mixed and, in the case of ZnSe, whether an inert (He) or reducing (H₂) carrier gas is used. At ambient temperatures in an inert carrier gas, the control of particle size exerted by pyridine decreases in the order ZnS > CdS > CdSe > ZnSe, although in hydrogen, the prereaction between Me₂Zn and H₂Se could be almost completely eliminated by raising the temperature. Further investigation of CdS deposits have been carried out by photoacoustic spectroscopy (PAS) to access the band-gap, and solid-state ¹³C and ¹¹³Cd NMR to probe the surface state of the particles. Elemental analysis and the NMR studies suggest that pyridine binds through the lone pair of the nitrogen to surface metal atoms on growing particles, inhibiting further particle growth. The particle size is greatly dependent upon the strength of the pyridine–surface metal atom interaction, the acidity of the EH bond (E=S or Se) and the polarity of the MMe bond (M=Zn or Cd). In hydrogen, it is proposed that amide species may form and be responsible for growth inhibition.

References

1. S. Fujiita, Y. Matsuda and A. Sasaki, J. Crystal Growth, 1984, 68, 231.
2. A. Yoshikawa, S. Muto, S. Yamaga and H. Kasai, J. Crystal Growth, 1988, 86, 279.
3. S. Yamaga, A. Yoshikawa and H. Kasai, J. Crystal Growth, 1988, 86, 252.
4. A. C. Jones, J. Crystal Growth, 1994, 145, 505.
5. P. J. Wright, B. Cockayne, A. J. Williams, A. C. Jones and E. D. Orrell, J. Crystal Growth, 1987, 84, 552.
6. M. J. Almond, M. P. Beer, M. G. B. Drew and D. A. Rice, J. Organomet. Chem., 1991, 421, 129.
7. B. Cockayne, P. J. Wright, A. J. Armstrong, A. C. Jones and E. D. Orrell, J. Crystal Growth, 1988, 91, 57.
8. A. C. Jones, J. Phys. Paris II, 1991, C2, 253.
9. K. F. Jensen, A. Annapragada, K. L. Ho, J.-S. Huh, S. Patnaik and S. Salim, J. Phys. Paris II, 1991, C2, 243.
10. P. J. Wright, P. J. Parbrook, B. Cockayne, A. C. Jones, E. D. Orrell, K. P. O'Donnell and B. Henderson, J. Crystal Growth, 1989, 94, 441.
11. P. J. Wright, B. Cockayne, P. J. Parbrook, A. C. Jones, P. O'Brien and J. R. Walsh, J. Crystal Growth, 1990, 104, 601.
12. M. J. Almond, M. P. Beer, K. Hagen, D. A. Rice and P. J. Wright, J. Mater. Chem., 1991, 1, 1065.
13. O. Briot, M. DiBlasio, T. Cloitre, N. Briot, P. Bigenwald, B. Gil, M. Averous, R. L. Aulombard, L. M. Smith, S. A. Rushworth and A. C. Jones, Mater. Res. Soc. Symp. Proc., 1994, 340, 515.
14. P. J. Wright, B. Cockayne, P. J. Parbrook, P. E. Oliver and A. C. Jones, J. Crystal Growth, 1991, 108, 525.
15. M. A. Malik, M. Motevalli, J. R. Walsh, P. O'Brien and A. C. Jones, J. Mater. Chem., 1995, 5, 731.
16. O. F. Z. Khan, P. O'Brien, P. A. Hamilton, J. R. Walsh and A. C. Jones, Chemtronics, 1989, 4, 244.
17. R. E. Linney and D. K. Russell, J. Mater. Chem., 1993, 3, 587.
18. H. Dumont, A. Marbeuf, J. Bouree and O. Gorochov, J. Mater. Chem., 1992, 2, 923.
19. H. Dumont, A. Marbeuf, J. Bouree and O. Gorochov, J. Mater. Chem., 1993, 3, 1075.
20. D. A. Jackson, J. Crystal Growth, 1989, 94, 459.
21. H. Weller, Angew. Chem., Int. Ed. Engl., 1993, 32, 41.
22. H. Weller, Adv. Mater., 1993, 5, 88.
23. X. Li, J. R. Fryer and D. J. Cole-Hamilton, J. Chem. Soc., Chem. Commun., 1994, 1715.
24. N. L. Pickett, D. F. Foster and D. J. Cole-Hamilton, J. Mater. Chem., 1996, 6, 507.
25. N. L. Pickett, D. F. Foster and D. J. Cole-Hamilton, J. Crystal Growth, 1997, 170, 476.
26. D. F. Foster and D. J. Cole-Hamilton, Inorg. Synth., 1997, 31, 29.
27. A. Rasencwaig, Chemical analysis, Vol 57 Photoacoustics and Photoacoustic Spectroscopy, Wiley, New York, 1980.
28. S. F. Bertram in Handbook of X-Rays, ed. E. F. Kaelble, McGraw-Hill, New York, 1967, pp 17–19.
29. S. W. Haggata, X. Li and D. J. Cole-Hamilton, J. Mater. Chem., 1996, 6, 1771.
30. A. Guinier, X-Ray Diffraction, W. H. Freeman, San Francisco, 1963, pp. 226–237.
31. R. B. Somoano, Angew. Chem., Int. Ed. Engl., 1978, 17, 238.
32. P. O'Brien and S. Haggata, Adv. Mater. Opt. Electron., 1995, 5, 117.
33. M. G. Bawendi, A. R. Kortan, M. L. Steigerwald and L. E. Brus, J. Chem. Phys, 1989, 91, 7282.
34. A. Baronnet, Rev. Mineral., 1992, 27, 231.
35. N. N. Greenwood and A. Earnshaw, Chemistry of the Elements, Pergamon, Oxford 1974.
36. A. J. De Koning, J. Boersma and G. J. M. Van Der Kerk, J, Organomet. Chem, 1980, 195, 1.
37. N. A. Bell and G. E. Coates, J. Chem. Soc. A, 1968, 823.
38. W. S. Rees, D. M. Green, T. J. Anderson, E. Bretschneider, B. Pathangey, C. Park and J. Kim, J. Electron. Mater., 1992, 21, 361.