Journal of Electronic Materials

, Volume 48, Issue 4, pp 2294–2300 | Cite as

Recyclable Phosphor Films: Three Water-Soluble Binder Systems Enabling the Recovery of Phosphor Powders in White LEDs

  • M. Hämmer
  • A. Gassmann
  • A. Reller
  • H. von Seggern
  • O. Gutfleisch
  • R. Stauber
  • J. ZimmermannEmail author


A recyclable luminescence down-conversion film as utilised in commercial white light-emitting diodes (LEDs) is introduced to avoid waste of valuable materials such as rare-earth metal-containing phosphors. As proof of principle, the commercial phosphor Y3Al5O12:Ce3+ is embedded in three easy soluble binders instead of the commonly utilised non-recyclable silicone binder. It will be demonstrated that these phosphor films allow for a highly efficient reuse of the phosphor. The investigated binders are, first, soluble sodium silicates (water glass) mixed with water in a ratio of 1:3, second, a 1 wt.%/vol.% solution of hydroxyethyl cellulose (HEC) in a 1:1 mixture of water and ethanol and, third, a 5 wt.%/vol.% solution of polyvinyl alcohol (PVA) in water. The phosphor-containing films show the same quality as comparable state-of-the-art phosphor converter films as demonstrated by preparation of fully functional white surface-mount device (SMD) LEDs based on commercially available blue SMD LED chips. It is demonstrated that the converter films can be recycled by dissolving the films in water at room temperature for HEC and PVA and at 60°C for the sodium silicates. Subsequently, the phosphor is reclaimed by sedimentation. The average recycling rates are 98.7 wt.% for sodium silicates, 95.6 wt.% for HEC and 98.0 wt.% for PVA. The phosphor does not suffer any losses of quality or functionality during this process as shown by fluorescence spectroscopy.


Design to recycle soluble sodium silicate polyvinyl alcohol hydroxyethyl cellulose phosphor converter film reuse 


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The authors wish to thank A.-L. Bachmann for performing the ICP-OES measurements, M. Kunkel for performing the IR spectroscopy and the carbon analysis (both from Fraunhofer Project Group IWKS) and G. Maas-Diegeler (from Fraunhofer ISC) for the use of the climate cabinet.

Conflict of interest

The authors declared that they have no conflict of interest.


  1. 1.
    Frost & Sullivan, The Future of Lighting: A New Paradigm is Being Driven by Energy Efficiency, Smart Technology, New Business Models, and LED Penetration, Frost & Sullivan (2016).Google Scholar
  2. 2.
    P. Schlotter, R. Schmidt, and J. Schneider, Appl. Phys. A (1997). Scholar
  3. 3.
    N.C. George, K.A. Denault, and R. Seshadri, Annu. Rev. Mater. Res. (2013). Scholar
  4. 4.
    H.-J. Byun, W.-S. Song, Y.-S. Kim, and H. Yang, J. Phys. D (2010). Scholar
  5. 5.
    Frost & Sullivan, Analysis of the Global LED Materials Market: Growth for Chemicals as Raw Materials to Outstrip Growth in the LED Market Itself, Frost & Sullivan (2014).Google Scholar
  6. 6.
    Y. Liu, J. Zou, M. Shi, B. Yang, Y. Han, W. Li, Z. Wang, H. Zhou, M. Li, and N. Jiang, Ceram. Int. (2018). Scholar
  7. 7.
    A.L. Hicks, T.L. Theis, and M.L. Zellner, J. Ind. Ecol. (2015). Scholar
  8. 8.
    J. Schleich, B. Mills, and E. Dütschke, Energy Policy (2014). Scholar
  9. 9.
    C. Bois, Alignment of phosphor properties for improvement of phosphor-converted LED performance (Darmstadt: Dissertation, 2014) Accessed 19 Dec 2018.
  10. 10.
    M. Yazdan Mehr, W.D. van Driel, and G.Q. Zhang, Microelectron. Reliab. (2014). Scholar
  11. 11.
    X. Shen, D.-F. Zhang, X.-W. Fan, G.-S. Hu, X.-B. Bian, and L. Yang, J. Mater. Sci. Mater. Electron. (2016). Scholar
  12. 12.
    A. Gassmann, J. Zimmermann, R. Gauß, R. Stauber, and O. Gutfleisch, LED Prof. Rev Trends Technol. Future Light. Solut. 56, 74 (2016).Google Scholar
  13. 13.
    Wacker Chemie AG, Technical data sheet for LUMISIL® 815 A/B, (2016), Accessed 18 Dec 2018.
  14. 14.
    Dow Coring Corporation, Dow Corning® OE-6635 Optical Encapsulant, (2013), Accessed 18 Dec 2018.
  15. 15.
    G.J. Ruiz-Mercado, M.A. Gonzalez, R.L. Smith, and D.E. Meyer, Resour. Conserv. Recycl. (2017). Scholar
  16. 16.
    P. Fulmek, C. Sommer, P. Hartmann, P. Pachler, H. Hoschopf, G. Langer, J. Nicolics, and F.P. Wenzl, Adv. Opt. Mater. (2013). Scholar
  17. 17.
    M. Franz and F.P. Wenzl, Crit. Rev. Environ. Sci. Technol. (2017). Scholar
  18. 18.
    S.M. Mizanur Rahman, J. Kim, G. Lerondel, Y. Bouzidi, K. Nomenyo, and L. Clerget, Resour. Conserv. Recycl. (2017). Scholar
  19. 19.
    M. Buchert, A. Manhart, D. Bleher, and D. Pingel, Recycling critical raw materials from waste electronic equipment (Freiburg: Öko-Institut e.V., 2012). Accessed 18 Dec 2018.
  20. 20.
    L. Tähkämö, M. Puolakka, L. Halonen, and G. Zissis, J. Light Vis. Environ. (2012). Scholar
  21. 21.
    D. Cai, G.R. Allen, and T. Glynne, Process for reclaiming inorganic powders from polymer-based coating compositions (US 9327309 B2, 2016).Google Scholar
  22. 22.
    M.A. Reuter and A. van Schaik, J. Sustain. Metall. (2015). Scholar
  23. 23.
    C. Helbig, C. Kolotzek, A. Thorenz, A. Reller, A. Tuma, M. Schafnitzel, and S. Krohns, Sustain. Mater. Technol. (2017). Scholar
  24. 24.
    G.A. Slack, D.W. Oliver, R.M. Chrenko, and S. Roberts, Phys. Rev. (1969). Scholar
  25. 25.
    G.H. Meeten, Optical Properties of Polymers (London: Elsevier Applied Science Publishers Ltd., 1986), pp. 1–62.Google Scholar
  26. 26.
    R.A. Shishkin, N.A. Erkhova, A.R. Beketov, and A.A. Elagin, J. Ceram. Sci. Technol. (2014). Scholar
  27. 27.
    Q.T. Pham, Food Freezing and Thawing Calculations (New York: Springer, 2014), pp. 5–24.Google Scholar
  28. 28.
    X. Xie, D. Li, T.-H. Tsai, J. Liu, P.V. Braun, and D.G. Cahill, Macromolecules (2016). Scholar
  29. 29.
    X.-G. Li, M.-R. Huang, and H. Bai, J. Appl. Polym. Sci. (1999).;2-K.Google Scholar
  30. 30.
    J. Lu, T. Wang, and L.T. Drzal, Compos. Part A (2008). Scholar
  31. 31.
    J.H. Kim, M. Kim, and J.-S. Yu, Environ. Sci. Technol. (2011). Scholar
  32. 32.
    J.J. Porter and J.J. Porter, Text. Chem. Color. 22, 21 (1990).Google Scholar
  33. 33.
    H. Thielking and M. Schmidt, Ullmann’s Encyclopedia of Industrial Chemistry (Weinheim: Wiley, 2000) Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  1. 1.Fraunhofer Project Group Materials Recycling and Resource Strategies IWKSHanauGermany
  2. 2.Institut für PhysikUniversität AugsburgAugsburgGermany
  3. 3.Institute of Materials Resource ManagementUniversität AugsburgAugsburgGermany
  4. 4.Institute of Material ScienceTechnische Universität DarmstadtDarmstadtGermany

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