Feature issue introduction: persistent and photostimulable phosphors – an established research field with clear challenges ahead

Persistent phosphors have the ability to emit light long after the excitation has ended, typically by using thermal energy to liberate previously trapped charges. Alternatively, also photons can be used for the detrapping, leading to optically stimulated luminescence (OSL). This particular field of phosphor research has seen a strong expansion over the past two decades, with a steady growth of the materials library, an improved structural and luminescence characterization and the development of novel applications. Despite this success, clear challenges lie ahead in terms of a deeper understanding of the trapping mechanism and an associated optimization of the energy storage capacity being crucial for many applications. This focus issue “Persistent and Photostimulable Phosphors” within Optical Materials Express features papers presented at the third International Workshop on Persistent and Photostimulable Phosphors (IWPPP 2015) held at the University of Texas at Arlington. ©2016 Optical Society of America OCIS codes: (160.2540) Fluorescent and luminescent materials; (160.5690) Rare-earthdoped materials; (160.2900) Optical storage materials; (300.6280) Spectroscopy, fluorescence and luminescence; (250.5230) Photoluminescence; (160.6990) Transitionmetal-doped materials References and links 1. P. F. Smet, K. Van den Eeckhout, O. Q. De Clercq, and D. Poelman, “Chapter 274 Persistent Phosphors,” in Handbook on the Physics and Chemistry of Rare Earths, J.-C. Bünzli, and V. K. Pecharsky, eds. (Elsevier, 2015), pp. 1–108. 2. W. Chen and J. Zhang, “Using nanoparticles to enable simultaneous radiation and photodynamic therapies for cancer treatment,” J. Nanosci. Nanotechnol. 6(4), 1159–1166 (2006). 3. L. Ma, X. Zou, B. Bui, W. Chen, K. H. Song, and T. Solberg, “X-ray excited ZnS:Cu,Co afterglow nanoparticles for photodynamic activation,” Appl. Phys. Lett. 105(1), 013702 (2014). 4. A. J. J. Bos, N. R. J. Poolton, J. Wallinga, A. Bessiere, and P. Dorenbos, “Energy levels in YPO4:Ce,Sm studied by thermally and optically stimulated luminescence,” Radiat. Meas. 45(3-6), 343–346 (2010). 5. Y. Katayama, B. Viana, D. Gourier, J. Xu, and S. Tanabe, “Photostimulation induced persistent luminescence in Y3Al2Ga3O12:Cr,” Opt. Mater. Express 6(4),1405–1413 (2016). 6. C. Tydtgat, K. W. Meert, D. Poelman, and P. F. Smet, “Optically stimulated detrapping during charging of persistent phosphors,” Opt. Mater. Express 6(3), 844–858 (2016). 7. P. F. Smet, D. Poelman, and M. P. Hehlen, “Focus issue introduction: persistent phosphors,” Opt. Mater. Express 2(4), 452–454 (2012). 8. M. Y. Peng, J. R. Qiu, and Q. Y. Zhang, “An introduction to the 2nd International Workshop on Persistent and Photostimulable Phosphors (IWPPP 2013),” Opt. Mater. 36(11), 1769–1770 (2014). 9. K. Van den Eeckhout, D. Poelman, and P. F. Smet, “Persistent luminescence in non-Eu-doped compounds: A review,” Materials (Basel) 6(7), 2789–2818 (2013). 10. K. Van den Eeckhout, P. F. Smet, and D. Poelman, “Persistent luminescence in Eu-doped compounds: A review,” Materials (Basel) 3(4), 2536–2566 (2010). 11. Y. Zhuang, Y. Katayama, J. Ueda, and S. Tanabe, “A brief review on red to near-infrared persistent luminescence in transition-metal-activated phosphors,” Opt. Mater. 36(11), 1907–1912 (2014). #262113 Received 28 Mar 2016; published 1 Apr 2016 © 2016 OSA 1 Apr 2016 | Vol. 6, No. 4 | DOI:10.1364/OME.6.001414 | OPTICAL MATERIALS EXPRESS 1414 12. J. Xu, J. Ueda, and S. Tanabe, “Design of deep-red persistent phosphors of Gd3Al5-xGaxO12:Cr transparent ceramics sensitized by Eu as an electron trap using conduction band engineering,” Opt. Mater. Express 5(5), 963–968 (2015). 13. Y. Katayama, H. Kobayashi, J. Ueda, B. Viana, and S. Tanabe, “Persistent luminescence properties of CrSm activated LaAlO3 perovskite,” Opt. Mater. Express, in press. 14. T. Maldiney, A. Bessière, J. Seguin, E. Teston, S. K. Sharma, B. Viana, A. J. J. Bos, P. Dorenbos, M. Bessodes, D. Gourier, D. Scherman, and C. Richard, “The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells,” Nat. Mater. 13(4), 418–426 (2014). 15. T. Matsuzawa, Y. Aoki, N. Takeuchi, and Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu,Dy,” J. Electrochem. Soc. 143(8), 2670–2673 (1996). 16. J. Botterman, J. J. Joos, and P. F. Smet, “Trapping and detrapping in SrAl2O4:Eu,Dy persistent phosphors: Influence of excitation wavelength and temperature,” Phys. Rev. B 90(8), 085147 (2014). 17. R. Shi, M. M. Qi, L. X. Ning, F. J. Pan, L. Zhou, W. J. Zhou, Y. C. Huang, and H. B. Liang, “Combined experimental and ab initio study of site preference of Ce in SrAl2O4,” J. Phys. Chem. C 119(33), 19326– 19332 (2015). 18. J. Bierwagen, S. Yoon, N. Gartmann, B. Walfort, and H. Hagemann, “Thermal and concentration dependent energy transfer of Eu in SrAl2O4,” Opt. Mater. Express 6(3), 793–803 (2016). 19. H. Hagemann, D. Lovy, S. Yoon, S. Pokrant, N. Gartmann, B. Walfort, and J. Bierwagen, “Wavelength dependent loading of traps in the persistent phosphor SrAl2O4:Eu, Dy,” J. Lumin. 170, 299–304 (2016). 20. Y. Jin, Y. Hu, L. Chen, G. Ju, H. Wu, Z. Mu, M. He, and F. Xue, “Luminescent properties of a green long persistent phosphor Li2MgGeO4:Mn,” Opt. Mater. Express 6(3), 929–937 (2016). 21. R. Yu, M. Yuan, Y. Xiong, J. Li, and J. Wang, “Structure characteristics and afterglow of BaZr4(PO4)6 phosphor,” Opt. Mater. Express 6(4), 1049–1055 (2016). 22. W. Ahn and Y. J. Kim, “Synthesis and up-conversion luminescence of Lu3Al5O12:Yb,Er,” Opt. Mater. Express 6(4), 1099–1105 (2016). 23. Z. Wang, W. Wang, J. Zhang, X. Ji, J. Li, J. Liang, S. Peng, Z. Ci, and Y. Wang, “Theoretical method to select appropriate codopants as efficient foreign electron traps for Lu3Al2Ga3O12:Tb/Ln persistent phosphor,” Opt. Mater. Express 6(4), 1186–1197 (2016). 24. S. Zhang, Y. Hu, L. Chen, Y. Fu, and G. Ju, “La3GaGe5O16:Cr phosphor: the near-infrared persistent luminescence,” Opt. Mater. Express 6(4), 1247–1255 (2016). 25. Z. Hu, D. Ye, X. Lan, W. Zhang, L. Luo, and Y. Wang, “Influence of co-doping Si ions on persistent luminescence of ZnGa2O4:Cr red phosphors,” Opt. Mater. Express 6(4), 1329–1338 (2016). 26. L. Li, K. Xu, Y. Wang, Z. Hu, and H. Zhao, “Enhanced persistent luminescence and photocatalytic properties of Ga2O3:Cr by In doping,” Opt. Mater. Express 6(4), 1122–1130 (2016). 27. D. Poelman, N. Avci, and P. F. Smet, “Measured luminance and visual appearance of multi-color persistent phosphors,” Opt. Express 17(1), 358–364 (2009). 28. Q. le Masne de Chermont, C. Chanéac, J. Seguin, F. Pellé, S. Maîtrejean, J.-P. Jolivet, D. Gourier, M. Bessodes, and D. Scherman, “Nanoprobes with near-infrared persistent luminescence for in vivo imaging,” Proc. Natl. Acad. Sci. U.S.A. 104(22), 9266–9271 (2007). 29. E. A. Mason, R. Lopez, and R. P. Mason, “Wavelength shifting of chemiluminescence using quantum dots to enhance tissue light penetration,” Opt. Mater. Express 6(4), 1384–1392 (2016).. 30. D. Gourier, A. Bessière, S. K. Sharma, L. Binet, B. Viana, N. Basavaraju, and K. R. Priolkar, “Origin of the visible light induced persistent luminescence of Cr-doped zinc gallate,” J. Phys. Chem. Solids 75(7), 826–