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Terahertz-based nanometrology: multispectral imaging of nanoparticles and nanoclusters in suspensions


Silica nanoparticles suspended in an organic solvent (nanosuspension) have been imaged and characterized via terahertz nanoscanning reconstructive three-dimension (3D) imaging technique. The size of individual silica nanoparticles in the suspension was quantified. In addition, the presence of nanoclusters along with their distribution in the suspension was visualized in 3D. It has also been qualitatively demonstrated that the volume fraction of solvent is significantly higher than that of the silica nanoparticles; an observation consistent with the composition of the nanosuspension in the present investigation. The measured size range of individual nanoparticles was found to be 10–12 nm, while the manufacturer’s specification indicates a nanoparticle size distribution in the range of 10 to 15 nm. However, a typical nanocluster size was determined to be 17.5 nm, thus indicating the presence of nanoparticles less than 10 nm. The nanometrology instrument used in this investigation was based on a dendrimer dipole excitation-based continuous wave terahertz source generating > 200 mW stable terahertz power.

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  • Cohen RD (1992) Development of the cluster-size distribution in flowing suspensions. AICHE J 38:1129–1134

    CAS  Article  Google Scholar 

  • Hassellöv M, Readman JW, Ranville JF, Tiede K (2008) Nanoparticle analysis and characterization methodologies in environmental risk assessment of engineered nanoparticles. Ecotoxicology 17(344):344–361.

    CAS  Article  Google Scholar 

  • Rahman A (2010) Stimulated emission of terahertz radiation from electro-optic dendrimer, Proc. SPIE 7601, Terahertz Technology and Applications III, 76010C, DOI:

  • Rahman A (2011) Dendrimer based terahertz time-domain spectroscopy and applications in molecular characterization. J Mol Struct 1006:59–65

    CAS  Article  Google Scholar 

  • Rahman A (2016) Simplest method of measuring nanoparticles’ size and size distribution on the surface and on sub-surface layers, Working Paper, December, pp. 1–5, DOI:

  • Rahman A (2017) Terahertz multispectral imaging of epitaxially grown semiconductors’ lattice defects, In 28th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC) 2017, Saratoga Springs, NY, pp. 45–50

  • Rahman A, Rahman AK (2016) Terahertz spectroscopic analysis and multispectral imaging of epitaxially grown semiconductors with nanometer resolution. Journal of Biosensors & Bioelectronics 7(4):1–6.

    Article  Google Scholar 

  • Rahman A, Rahman AK, Yamamoto T, Kitagawa H (2016a) Terahertz sub-nanometer sub-surface imaging of 2D materials. Journal of Biosensors & Bioelectronics 7(3):1–6.

    Article  Google Scholar 

  • Rahman A, Rahman AK, Tomalia DA (2016b) Dendrimer dipole excitation: a new mechanism for terahertz generation. Journal of Biosensors & Bioelectronics 7(1):1–6

    Article  Google Scholar 

  • Rahman A, Rahman AK, Tomalia DA (2017) Engineering dendrimers to produce dendrimer dipole excitation based terahertz radiation sources suitable for spectrometry, molecular and biomedical imaging. Nanoscale Horiz 2:127–134

    CAS  Article  Google Scholar 

  • Tomalia DA (2012) Dendritic effects: dependency of dendritic nano-periodic property patterns on critical nanoscale design parameters (CNDPs). New J Chem 36:264–281

    CAS  Article  Google Scholar 

  • Tomalia DA, Khanna SN (2016) A systematic framework and nanoperiodic concept for unifying nanoscience: hard/soft nanoelements, superatoms, meta-atoms, new emerging properties, periodic property patterns, and predictive mendeleev-like nanoperiodic tables. Chem Rev 116:2705–2774

    CAS  Article  Google Scholar 

  • Wang XZ, Lande L, Rui FL, Tweedie RJ, Primrose K, Corbett J, McNeil-Watson FK (2009) Online characterisation of nanoparticle suspensions using dynamic light scattering, ultrasound spectroscopy and process tomography. Chem Eng Res Des 87(6):874–884

    CAS  Article  Google Scholar 

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Correspondence to Anis Rahman.

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This research has been conducted at Applied Research and Photonics, Harrisburg, PA by the initiatives of Dr. Anis Rahman and in consultation with Dr. Donald Tomalia.

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The authors declare that they have no conflict of interest.

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This article is part of the topical collection: Unifying Concepts for Nanoscience and Nanosystems: 20th Anniversary Issue

Donald Tomalia, Paolo Milani and Kenneth Dawson, co-editors

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Rahman, A., Tomalia, D.A. Terahertz-based nanometrology: multispectral imaging of nanoparticles and nanoclusters in suspensions. J Nanopart Res 20, 297 (2018).

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  • Terahertz multispectral reconstructive imaging
  • Nanoslurry
  • Silica nanoparticles
  • Nanoclusters
  • Nanosuspension
  • Nanoscale instrumentation