Chemical vapor synthesis (CVS) enables the generation of nanoparticles with well-defined local, crystal and microstructure at an excellent control of process parameters, especially the time-temperature profile T(t).
The phase formation during gas phase synthesis is poorly understood. Ex situ methods suffer from aging of the nanoparticles, oxidation during storage and sample preparation and lead to a loss of information especially in case of small nanoparticles, transient or metastable phases.
The formation of nanoparticles is a complex, dynamic process and can be studied in detail by in situ / operando methods where and while particles are (trans-)formed:
- Aerosol Mass Spectrometry (AMS) to study molecular and particle species
- Laser Induced Fluorescence (LIF) to measure the gas temperature in the hot wall reactor
- X-ray absorption spectroscopy (XAS, XANES and EXAFS) to determine local and electronic structure of precursor vapor and nanoparticles
- Small angle X-ray scattering (SAXS) to study microstructure and morphology of the nanoparticles
- Wide angle X-ray scattering (WAXS) to investigate the formation of crystalline phases and the crystal structure
- Combination of SAXS and WAXS provides detailed information about agglomeration
- Combination of XAS and WAXS enables the study of nucleation
- S. R. Joshi, M. A. Schroer, and M. Winterer, In Situ X-ray Scattering of Tin Oxide Nanoparticles during Chemical Vapor Synthesis, Chem. Mater. 37 (2025) 5710-5723
- A. Levish, S. Joshi, and M. Winterer, Chemical Vapor Synthesis of Nanocrystalline Iron Oxides, Applications in Energy and Combustion Science 15 (2023) 100177, 9pp.
- M. A. Schroer, A. Levish, Y. Yildizlar, M. Stepponat, and Markus Winterer, A versatile chemical vapor synthesis reactor for in situ x-ray scattering and spectroscopy, Rev. Sci. Instrum. 93 (2022) 113706, 11pp.
- A. Levish and M. Winterer, Formation of polymorphs and pores in small nanocrystalline iron oxide particles, Sci. Rep. 12 (2022) 15291, 11pp
- A. Levish and M. Winterer, In situ cell for x-ray absorption spectroscopy of low volatility compound vapors, Rev. Sci. Instr. 91 (2020), 063101, 7pp
- C. Notthoff, C. Schilling, and M. Winterer, Gas temperature measurements inside a hot wall chemical vapor synthesis reactor, Review of Scientific Instruments 83/11 (2012), 114904
- M. Ali, M. D. Donakowski, C. Mayer, and M. Winterer, Chemical vapor functionalization: a continuous production process for functionalized ZnO nanoparticles, Journal of Nanoparticle Research 14 (2012), 689
- I. K. Lee and M. Winterer, Aerosol mass spectrometer for the in situ analysis of chemical vapor synthesis processes in hot wall reactors, Rev. Sci. Instr. 76 (2005) 095104, 8pp.