Skip to main content

Multi-responsive deep-ultraviolet emission in praseodymium-doped phosphors for microbial sterilization



Perusing multimode luminescent materials capable of being activated by diverse excitation sources and realizing multi-responsive emission in a single system remains a challenge. Herein, we utilize a heterovalent substituting strategy to realize multimode deep-ultraviolet (UV) emission in the defect-rich host Li2CaGeO4 (LCGO). Specifically, the Pr3+ substitution in LCGO is beneficial to activating defect site reconstruction including the generation of cation defects and the decrease of oxygen vacancies. Regulation of different traps in LCGO:Pr3+ presents persistent luminescence and photo-stimulated luminescence in a synergetic fashion. Moreover, the up-conversion luminescence appears with the aid of the 4f discrete energy levels of Pr3+ ions, wherein incident visible light is partially converted into germicidal deep-UV radiation. The multi-responsive character enables LCGO:Pr3+ to response to convenient light sources including X-ray tube, standard UV lamps, blue and near-infrared lasers. Thus, a dual-mode optical conversion strategy for inactivating bacteria is fabricated, and this multi-responsive deep-UV emitter offers new insights into developing UV light sources for sterilization applications. Heterovalent substituting in trap-mediated host lattice also provides a methodological basis for the construction of multi-mode luminescent materials.


开发能够被不同激发光源激发, 并在同一体系中实现多响应发 射的多模态发光材料是发光材料领域的一个挑战. 本文采用一种异价 掺杂策略, 在富含缺陷的Li2CaGeO4 (LCGO)基质中实现了Pr3+掺杂的 多模式深紫外发射. LCGO:Pr3+多响应特性使其能够被常见的光源, 包 括X射线管、标准紫外灯、蓝光和近红外激光器激发. Pr3+掺杂产生并 重建LCGO材料中的缺陷位点, 包括阳离子缺陷的产生和氧空位的减 少, 进而调控了陷阱分布, 使得该材料同时表现出余辉发光和光激励发 光. 基于Pr3+离子的4f离散能级, 该材料还表现出上转换发光, 入射的可 见光可转化为用于杀菌的深紫外发射. 基于此, 本文设计了一种双模光 转换策略用于灭活细菌. 这种多响应的深紫外发射体为开发用于杀菌 的紫外光源提供了新的思路. 在以陷阱为媒介的基质晶格中实施异价 掺杂或者取代也为构建多模发光材料提供了可行途径.


  1. 1

    Zhou X, Qiao J, Xia Z. Learning from mineral structures toward new luminescence materials for light-emitting diode applications. Chem Mater, 2021, 33: 1083–1098

    CAS  Article  Google Scholar 

  2. 2

    Lyu T, Dorenbos P. Vacuum-referred binding energies of bismuth and lanthanide levels in ARE(Si,Ge)O4 (A = Li, Na; RE = Y, Lu): Toward designing charge-carrier-trapping processes for energy storage. Chem Mater, 2020, 32: 1192–1209

    CAS  Article  Google Scholar 

  3. 3

    Wang X, Chen Y, Liu F, et al. Solar-blind ultraviolet-C persistent luminescence phosphors. Nat Commun, 2020, 11: 2040

    CAS  Article  Google Scholar 

  4. 4

    Song K, Mohseni M, Taghipour F. Application of ultraviolet light-emitting diodes (UV-LEDs) for water disinfection: A review. Water Res, 2016, 94: 341–349

    CAS  Article  Google Scholar 

  5. 5

    Baron ED, Stevens SR. Phototherapy for cutaneous T-cell lymphoma. Dermatol Ther, 2003, 16: 303–310

    Article  Google Scholar 

  6. 6

    Chen J, Loeb S, Kim JH. LED revolution: Fundamentals and prospects for UV disinfection applications. Environ Sci-Water Res Technol, 2017, 3: 188–202

    CAS  Article  Google Scholar 

  7. 7

    Sharma VK, Tan ST, Haiyang Z, et al. On-chip mercury-free deep-UV light-emitting sources with ultrahigh germicidal efficiency. Adv Opt Mater, 2021, 9: 2100072

    CAS  Article  Google Scholar 

  8. 8

    Shining a light on COVID-19. Nat Photonics, 2020, 14: 337

    Article  CAS  Google Scholar 

  9. 9

    Ronda C. Challenges in application of luminescent materials, a tutorial overview. Prog Electromagn Res, 2014, 147: 81–93

    Article  Google Scholar 

  10. 10

    Yan S, Liu F, Zhang J, et al. Persistent emission of narrowband ultraviolet-B light upon blue-light illumination. Phys Rev Appl, 2020, 13: 044051

    CAS  Article  Google Scholar 

  11. 11

    Yan S, Gao Q, Zhao X, et al. Charging Gd3Ga5O12:Pr3+ persistent phosphor using blue lasers. J Lumin, 2020, 226: 117427

    CAS  Article  Google Scholar 

  12. 12

    Yan S, Liang Y, Chen Y, et al. Ultraviolet-C persistent luminescence from the Lu2SiO5:Pr3+ persistent phosphor for solar-blind optical tagging. Dalton Trans, 2021, 50: 8457–8466

    CAS  Article  Google Scholar 

  13. 13

    Yang YM, Li ZY, Zhang JY, et al. X-ray-activated long persistent phosphors featuring strong UVC afterglow emissions. Light Sci Appl, 2018, 7: 88

    Article  CAS  Google Scholar 

  14. 14

    Yin Z, Yuan P, Zhu Z, et al. Pr3+ doped Li2SrSiO4: An efficient visible-ultraviolet C up-conversion phosphor. Ceramics Int, 2021, 47: 4858–4863

    CAS  Article  Google Scholar 

  15. 15

    Qiao J, Xia Z, Zhang Z, et al. Near UV-pumped yellow-emitting Sr9MgLi(PO4)7:Eu2+ phosphor for white-light LEDs. Sci China Mater, 2018, 61: 985–992

    CAS  Article  Google Scholar 

  16. 16

    Wickleder MS. Inorganic lanthanide compounds with complex anions. Chem Rev, 2002, 102: 2011–2088

    CAS  Article  Google Scholar 

  17. 17

    Qin X, Liu X, Huang W, et al. Lanthanide-activated phosphors based on 4f-5d optical transitions: Theoretical and experimental aspects. Chem Rev, 2017, 117: 4488–4527

    CAS  Article  Google Scholar 

  18. 18

    Zhang JC, Pan C, Zhu YF, et al. Achieving thermo-mechano-opto-responsive bitemporal colorful luminescence via multiplexing of dual lanthanides in piezoelectric particles and its multidimensional anticounterfeiting. Adv Mater, 2018, 30: 1804644

    Article  CAS  Google Scholar 

  19. 19

    Ren Y, Yang Z, Wang Y, et al. Reversible multiplexing for optical information recording, erasing, and reading-out in photochromic BaMgSiO4:Bi3+ luminescence ceramics. Sci China Mater, 2020, 63: 582–592

    CAS  Article  Google Scholar 

  20. 20

    Du Y, Ai X, Li Z, et al. Visible-to-ultraviolet light conversion: Materials and applications. Adv Photo Res, 2021, 2: 2000213

    Article  Google Scholar 

  21. 21

    Du Y, Wang Y, Deng Z, et al. Blue-pumped deep ultraviolet lasing from lanthanide-doped Lu6O5F8 upconversion nanocrystals. Adv Opt Mater, 2020, 8: 1900968

    CAS  Article  Google Scholar 

  22. 22

    Tanner PA, Mak CSK, Faucher MD, et al. 4f-5d transitions of Pr3+ in elpasolite lattices. Phys Rev B, 2003, 67: 115102

    Article  CAS  Google Scholar 

  23. 23

    Hu C, Sun C, Li J, et al. Visible-to-ultraviolet upconversion in Pr3+: Y2SiO5 crystals. Chem Phys, 2006, 325: 563–566

    CAS  Article  Google Scholar 

  24. 24

    Cates EL, Wilkinson AP, Kim JH. Delineating mechanisms of upconversion enhancement by Li+ codoping in Y2SiO5:Pr3+. J Phys Chem C, 2012, 116: 12772–12778

    CAS  Article  Google Scholar 

  25. 25

    Cates EL, Cho M, Kim JH. Converting visible light into UVC: Microbial inactivation by Pr3+-activated upconversion materials. Environ Sci Technol, 2011, 45: 3680–3686

    CAS  Article  Google Scholar 

  26. 26

    Cates EL, Wilkinson AP, Kim JH. Visible-to-UVC upconversion efficiency and mechanisms of Lu7O6F9:Pr3+ and Y2SiO5:Pr3+ ceramics. J Lumin, 2015, 160: 202–209

    CAS  Article  Google Scholar 

  27. 27

    Dorenbos P. The 5d level positions of the trivalent lanthanides in inorganic compounds. J Lumin, 2000, 91: 155–176

    CAS  Article  Google Scholar 

  28. 28

    Srivastava AM. Aspects of Pr3+ luminescence in solids. J Lumin, 2016, 169: 445–449

    CAS  Article  Google Scholar 

  29. 29

    Li Y, Gecevicius M, Qiu J. Long persistent phosphors—From fundamentals to applications. Chem Soc Rev, 2016, 45: 2090–2136

    CAS  Article  Google Scholar 

  30. 30

    Li H, Liu Q, Ma J-, et al. Theory-guided defect tuning through topo-chemical reactions for accelerated discovery of UVC persistent phosphors. Adv Opt Mater, 2020, 8: 1901727

    CAS  Article  Google Scholar 

  31. 31

    Zhou X, Ju G, Dai T, et al. Li5Zn8Ga5Ge9O36:Cr3+, Ti4+: A long persistent phosphor excited in a wide spectral region from UV to red light for reproducible imaging through biological tissue. Chem Asian J, 2019, 14: 1506–1514

    CAS  Article  Google Scholar 

  32. 32

    Gard JA, West AR. Preparation and crystal structure of Li2CaSiO4 and isostructural Li2CaGeO4. J Solid State Chem, 1973, 7: 422–427

    CAS  Article  Google Scholar 

  33. 33

    Blasse G. Interaction between optical centers and their surroundings: An inorganic chemist’s approach. Adv Inorg Chem, 1990, 35: 319–402

    CAS  Article  Google Scholar 

  34. 34

    Ogasawara H, Kotani A, Potze R, et al. Praseodymium 3d- and 4d-core photoemission spectra of Pr2O3. Phys Rev B, 1991, 44: 5465–5469

    CAS  Article  Google Scholar 

  35. 35

    Yang W, Li J, Liu B, et al. Multi-wavelength tailoring of a ZnGa2O4 nanosheet phosphor via defect engineering. Nanoscale, 2018, 10: 19039–19045

    CAS  Article  Google Scholar 

  36. 36

    Ueda J, Leaño JL, Richard C, et al. Broadband near-infrared persistent luminescence of Ba[Mg2Al2N4] with Eu2+ and Tm3+ after red light charging. J Mater Chem C, 2019, 7: 1705–1712

    CAS  Article  Google Scholar 

  37. 37

    Simmons EL. Diffuse reflectance spectroscopy: A comparison of the theories. Appl Opt, 1975, 14: 1380–1386

    CAS  Article  Google Scholar 

  38. 38

    van Pieterson L, Reid MF, Wegh RT, et al. 4fn→4fn−15d transitions of the light lanthanides: Experiment and theory. Phys Rev B, 2002, 65: 045113

    Article  CAS  Google Scholar 

  39. 39

    Kowalski W. UV Surface Disinfection. In: Kowalski W (ed.). Ultraviolet Germicidal Irradiation Handbook. Berlin, Heidelberg: Springer. 2009. 233–254.

    Chapter  Google Scholar 

  40. 40

    Sasaki N, Yamashita T, Kasahara K, et al. UVB exposure prevents atherosclerosis by regulating immunoinflammatory responses. Arterioscler Thromb Vasc Biol, 2017, 37: 66–74

    CAS  Article  Google Scholar 

  41. 41

    Maldiney T, Bessière A, Seguin J, et al. The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells. Nat Mater, 2014, 13: 418–426

    CAS  Article  Google Scholar 

  42. 42

    Chen X, Li Y, Huang K, et al. Trap energy upconversion-like near-infrared to near-infrared light rejuvenateable persistent luminescence. Adv Mater, 2021, 33: 2008722

    CAS  Article  Google Scholar 

  43. 43

    Klasens HA, Garlick GFJ, Gibson AF. Discussion on “the electron trap mechanism of luminescence in sulphide and silicate phosphors”. Proc Phys Soc, 1948, 61: 101–102

    Article  Google Scholar 

  44. 44

    Van den Eeckhout K, Bos AJJ, Poelman D, et al. Revealing trap depth distributions in persistent phosphors. Phys Rev B, 2013, 87: 045126

    Article  CAS  Google Scholar 

  45. 45

    Chen R. On the calculation of activation energies and frequency factors from glow curves. J Appl Phys, 1969, 40: 570–585

    CAS  Article  Google Scholar 

  46. 46

    Chen F, Di H, Wang Y, et al. Small-molecule targeting of a diapophytoene desaturase inhibits S. aureus virulence. Nat Chem Biol, 2016, 12: 174–179

    CAS  Article  Google Scholar 

Download references


This work was supported by the National Natural Science Foundation of China (51961145101 and 51972118), the International Cooperation Project of National Key Research and Development Program of China (2021YFE0105700), Guangzhou Science & Technology Project (202007020005), and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137). The authors also thank Jiarong Liang and Prof. Bingfu Lei at South China Agricultural University for assistance with bactericidal inactivation.

Author information



Corresponding author

Correspondence to Zhiguo Xia.

Additional information

Author contributions

Zhou X performed the experiments and wrote the paper with support from Xia Z. Zhao Y performed the theoretical simulations. All authors contributed to the general discussion.

Conflict of interest

The authors declare that they have no conflict of interest.

Xinquan Zhou is a PhD student at the South China University of Technology. He completed his bachelor degree at the University of Jinan in 2017 and received the master degree from Guangdong University of Technology in 2020. His research mainly focuses on the rare-earth-ions-activated long persistent phosphors and luminescent materials for LEDs.

Zhiguo Xia is currently a professor of materials chemistry and physics at the South China University of Technology. He obtained his bachelor degree in 2002 and master degree in 2005 from Beijing Technology and Business University, and he received his PhD degree from Tsinghua University in 2008. His research interests are in designing of new rare-earth phosphors and luminescent metal halides for emerging photonics applications by integrating structural discovery, modification and structure-property relation studies.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Zhou, X., Qiao, J., Zhao, Y. et al. Multi-responsive deep-ultraviolet emission in praseodymium-doped phosphors for microbial sterilization. Sci. China Mater. (2021).

Download citation


  • phosphor
  • deep ultraviolet
  • multi-mode luminescence
  • sterilization