Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

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

  • 81 Accesses

  • 1 Citations


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.

This is a preview of subscription content, log in to check access.


  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).

  2. 2.

    P. Schlotter, R. Schmidt, and J. Schneider, Appl. Phys. A (1997). https://doi.org/10.1007/s003390050498.

  3. 3.

    N.C. George, K.A. Denault, and R. Seshadri, Annu. Rev. Mater. Res. (2013). https://doi.org/10.1146/annurev-matsci-073012-125702.

  4. 4.

    H.-J. Byun, W.-S. Song, Y.-S. Kim, and H. Yang, J. Phys. D (2010). https://doi.org/10.1088/0022-3727/43/19/195401.

  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).

  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). https://doi.org/10.1016/j.ceramint.2017.10.056.

  7. 7.

    A.L. Hicks, T.L. Theis, and M.L. Zellner, J. Ind. Ecol. (2015). https://doi.org/10.1111/jiec.12281.

  8. 8.

    J. Schleich, B. Mills, and E. Dütschke, Energy Policy (2014). https://doi.org/10.1016/j.enpol.2014.04.028.

  9. 9.

    C. Bois, Alignment of phosphor properties for improvement of phosphor-converted LED performance (Darmstadt: Dissertation, 2014) https://doi.org/http://tuprints.ulb.tu-darmstadt.de/4179/1/Dissertation.pdf. Accessed 19 Dec 2018.

  10. 10.

    M. Yazdan Mehr, W.D. van Driel, and G.Q. Zhang, Microelectron. Reliab. (2014). https://doi.org/10.1016/j.microrel.2014.03.014.

  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). https://doi.org/10.1007/s10854-015-3841-2.

  12. 12.

    A. Gassmann, J. Zimmermann, R. Gauß, R. Stauber, and O. Gutfleisch, LED Prof. Rev Trends Technol. Future Light. Solut. 56, 74 (2016).

  13. 13.

    Wacker Chemie AG, Technical data sheet for LUMISIL® 815 A/B, (2016), https://datasheets.globalspec.com/ds/3282/WackerChemical/BE5017B8-9030-41F9-A70C-7558224C311E. Accessed 18 Dec 2018.

  14. 14.

    Dow Coring Corporation, Dow Corning® OE-6635 Optical Encapsulant, (2013), http://resources.imart360.com/resources/files/techcentres/%E3%80%90TDS%E3%80%91DC_OE6635B_EN.pdf. Accessed 18 Dec 2018.

  15. 15.

    G.J. Ruiz-Mercado, M.A. Gonzalez, R.L. Smith, and D.E. Meyer, Resour. Conserv. Recycl. (2017). https://doi.org/10.1016/j.resconrec.2017.07.009.

  16. 16.

    P. Fulmek, C. Sommer, P. Hartmann, P. Pachler, H. Hoschopf, G. Langer, J. Nicolics, and F.P. Wenzl, Adv. Opt. Mater. (2013). https://doi.org/10.1002/adom.201300207.

  17. 17.

    M. Franz and F.P. Wenzl, Crit. Rev. Environ. Sci. Technol. (2017). https://doi.org/10.1080/10643389.2017.1370989.

  18. 18.

    S.M. Mizanur Rahman, J. Kim, G. Lerondel, Y. Bouzidi, K. Nomenyo, and L. Clerget, Resour. Conserv. Recycl. (2017). https://doi.org/10.1016/j.resconrec.2017.04.013.

  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). https://www.oeko.de/oekodoc/1375/2012-010-en.pdf. Accessed 18 Dec 2018.

  20. 20.

    L. Tähkämö, M. Puolakka, L. Halonen, and G. Zissis, J. Light Vis. Environ. (2012). https://doi.org/10.2150/jlve.36.44.

  21. 21.

    D. Cai, G.R. Allen, and T. Glynne, Process for reclaiming inorganic powders from polymer-based coating compositions (US 9327309 B2, 2016).

  22. 22.

    M.A. Reuter and A. van Schaik, J. Sustain. Metall. (2015). https://doi.org/10.1007/s40831-014-0006-0.

  23. 23.

    C. Helbig, C. Kolotzek, A. Thorenz, A. Reller, A. Tuma, M. Schafnitzel, and S. Krohns, Sustain. Mater. Technol. (2017). https://doi.org/10.1016/j.susmat.2017.01.004.

  24. 24.

    G.A. Slack, D.W. Oliver, R.M. Chrenko, and S. Roberts, Phys. Rev. (1969). https://doi.org/10.1103/physrev.177.1308.

  25. 25.

    G.H. Meeten, Optical Properties of Polymers (London: Elsevier Applied Science Publishers Ltd., 1986), pp. 1–62.

  26. 26.

    R.A. Shishkin, N.A. Erkhova, A.R. Beketov, and A.A. Elagin, J. Ceram. Sci. Technol. (2014). https://doi.org/10.4416/jcst2014-00005.

  27. 27.

    Q.T. Pham, Food Freezing and Thawing Calculations (New York: Springer, 2014), pp. 5–24.

  28. 28.

    X. Xie, D. Li, T.-H. Tsai, J. Liu, P.V. Braun, and D.G. Cahill, Macromolecules (2016). https://doi.org/10.1021/acs.macromol.5b02477.

  29. 29.

    X.-G. Li, M.-R. Huang, and H. Bai, J. Appl. Polym. Sci. (1999). https://doi.org/10.1002/(SICI)1097-4628(19990929)73:142927::AID-APP173.0.CO;2-K.

  30. 30.

    J. Lu, T. Wang, and L.T. Drzal, Compos. Part A (2008). https://doi.org/10.1016/j.compositesa.2008.02.003.

  31. 31.

    J.H. Kim, M. Kim, and J.-S. Yu, Environ. Sci. Technol. (2011). https://doi.org/10.1021/es103510r.

  32. 32.

    J.J. Porter and J.J. Porter, Text. Chem. Color. 22, 21 (1990).

  33. 33.

    H. Thielking and M. Schmidt, Ullmann’s Encyclopedia of Industrial Chemistry (Weinheim: Wiley, 2000)https://doi.org/10.1002/14356007.a05_461.pub2.

Download references


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.

Author information

Correspondence to J. Zimmermann.

Ethics declarations

Conflict of interest

The authors declared that they have no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Hämmer, M., Gassmann, A., Reller, A. et al. Recyclable Phosphor Films: Three Water-Soluble Binder Systems Enabling the Recovery of Phosphor Powders in White LEDs. Journal of Elec Materi 48, 2294–2300 (2019). https://doi.org/10.1007/s11664-019-06936-x

Download citation


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