Research ArticleMATERIALS SCIENCE

Ultralong room temperature phosphorescence from amorphous organic materials toward confidential information encryption and decryption

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Science Advances  04 May 2018:
Vol. 4, no. 5, eaas9732
DOI: 10.1126/sciadv.aas9732
  • Fig. 1 Rational design strategy of URTP from amorphous organic materials.

    (A) Chemical structures of G and PVA and the fabrication of G-doped PVA films for URTP. (B) Schematic illustration of URTP processes in G-doped PVA films. DIW, deionized water.

  • Fig. 2 Photophysical properties of the PVA film doped with different concentrations of G.

    Phosphorescence spectra of the PVA film doped with different concentrations of G (λex = 280 nm) at room temperature. (A) Unirradiated. (B) 254-nm UV light irradiation for 65 min. (C) Phosphorescent lifetime of these G-doped PVA films at room temperature, monitored at 480 nm and λex = 280 nm. (D) Snapshots of these G-doped PVA films upon irradiation by a 254-nm UV lamp for 65 min, followed by recording URTP at different time intervals in the dark under ambient conditions.

  • Fig. 3 Irradiation time-dependent measurements of the photophysical properties of the PVA-100-3mg film.

    (A) Phosphorescence spectra of the PVA-100-3mg film upon light irradiation at different times (λex = 280 nm). (B) Phosphorescent decay profiles of the PVA-100-3mg film at different irradiation times at room temperature (monitored at 480 nm, λex = 280 nm). (C) Time-dependent luminescent spectra of the PVA-100-3mg film at different irradiation times followed by turning off the UV light (delayed time: approximately 50 ms) at room temperature. (D) Comparison of the emission observed at different time intervals before and after turning off the light excitation at room temperature.

  • Fig. 4 Schematic diagram for achieving URTP in G-doped PVA films and irradiation time-dependent 1H NMR spectra of the PVA-100-3mg film.

    (A) Unirradiated G-doped PVA films with substantial H-bond formation from G-G, G-PVA, and PVA-PVA. (B) Irradiated G-doped PVA films by a 254-nm UV light (irradiation time ≤65 min) with cross-linked bond (C–O–C) formation between PVA chains. (C) Irradiated G-doped PVA films (irradiation time >65 min) with the rearrangement of H-bonds from G-G, G-PVA, and PVA-PVA. (D) 1H NMR spectra of G, PVA-100, and PVA-100-3mg films at different irradiation times in DMSO-d6. The inset shows the chemical structures of G (up) and PVA-100 (down).

  • Fig. 5 Photophysical properties of different G-doped PVA matrices upon irradiation by a 254-nm UV light for 65 min.

    (A) Phosphorescence spectra of PVA-100-3mg, PVA-87-3mg, and PVA-80-3mg films upon irradiation by a 254-nm UV 1ight (λex = 280 nm) for 65 min. (B) Phosphorescent decay profiles of PVA-100-3mg, PVA-87-3mg, and PVA-80-3mg films (monitored at 480 nm, λex = 280 nm). The inset shows the chemical structures of PVA-100, PVA-87, PVA-80, and PVAc. (C) Plots of phosphorescence emission intensity at 480 nm versus temperature (293 to 363 K) for PVA-100-3mg, PVA-87-3mg, and PVA-80-3mg films (λex = 280 nm). (D) Plots of phosphorescent lifetime versus temperature (293 to 363 K) for PVA-100-3mg, PVA-87-3mg, and PVA-80-3mg films (monitored at 480 nm, λex = 280 nm).

  • Fig. 6 Luminescent G-doped PVA film patterns fabricated via green screen printing.

    (A) Green screen printing without any inks using the lotus flower screen plate. First, G-doped PVA films were fabricated through drop-coating the G-PVA solution on a clean glass substrate, followed by drying at 65°C for 3 hours. Second, the screen plate of the lotus flower was covered on G-doped PVA films. Third, the covered PVA films were irradiated by a 254-nm UV lamp for 65 min to finish the screen printing progress. No patterns on the films were observed under sunlight. Clear patterns were observed upon exposure to the 254-nm UV lamp, and these patterns were still visible for several seconds after turning off the UV lamp. (B) Several complicated patterns by green screen printing technology after removing the excitation source. (C) More advanced anti-counterfeiting technology through doping AlQ3 into G-doped PVA films. (D) Reversible patterns of the lotus flower after removing the excitation source under different conditions. (E) Schematic illustration of the URTP process in the G-doped PVA films.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/5/eaas9732/DC1

    Supplementary Materials and Methods

    fig. S1. Synthetic procedure of compound G.

    fig. S2. Characterization of compound G.

    fig. S3. Fluorescence and phosphorescence spectra of G-doped PVA films.

    fig. S4. Phosphorescence decay profiles of G-doped PVA films.

    fig. S5. Photophysical properties of G-doped PVA films.

    fig. S6. FTIR and Raman spectra of G-doped PVA films.

    fig. S7. 1H NMR spectra of compounds.

    fig. S8. XPS spectra of the PVA-100-3mg film.

    fig. S9. UV-Vis spectra of the PVA-100-3mg film.

    fig. S10. Thermal properties and XRD patterns of the PVA-100-3mg film.

    fig. S11. SEM images of G-doped PVA films.

    fig. S12. Photophysical properties of the PVA-100-3mg film.

    fig. S13. Temperature-dependent photophysical properties of the PVA-100-3mg film.

    fig. S14. Excitation wavelength–dependent photophysical properties of the PVA-100-3mg film.

    fig. S15. Photophysical properties of G-doped different PVA matrix films.

    fig. S16. Photophysical properties and molecular structures.

    fig. S17. FTIR spectra, XRD patterns, and SEM images of the PVA-100-3mg film under different conditions.

    fig. S18. Phosphorescence emission spectra of patterns for the lotus flower under different conditions.

    fig. S19. Green screen printing procedures without using any inks.

    table S1. Photophysical data of PVA films by doping different concentrations of G.

    table S2. Photophysical data of the PVA-100-3mg film at different irradiation times under a 254-nm UV lamp.

    table S3. Photophysical data of the PVA-100-3mg film at different temperatures.

    table S4. Photophysical data of the PVA-100-3mg film at different excitation wavelengths under ambient conditions.

    movie S1. Appearance of the emitting G-doped PVA films when UV light is on and off.

    movie S2. Appearance of the emitting PVA-100-3mg film when UV light is on and off.

    movie S3. Imaging of the logo of the lotus flower.

    movie S4. Imaging of the logo of the lotus flower containing AlQ3.

    Reference (38)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • fig. S1. Synthetic procedure of compound G.
    • fig. S2. Characterization of compound G.
    • fig. S3. Fluorescence and phosphorescence spectra of G-doped PVA films.
    • fig. S4. Phosphorescence decay profiles of G-doped PVA films.
    • fig. S5. Photophysical properties of G-doped PVA films.
    • fig. S6. FTIR and Raman spectra of G-doped PVA films.
    • fig. S7. 1H NMR spectra of compounds.
    • fig. S8. XPS spectra of the PVA-100-3mg film.
    • fig. S9. UV-Vis spectra of the PVA-100-3mg film.
    • fig. S10. Thermal properties and XRD patterns of the PVA-100-3mg film.
    • fig. S11. SEM images of G-doped PVA films.
    • fig. S12. Photophysical properties of the PVA-100-3mg film.
    • fig. S13. Temperature-dependent photophysical properties of the PVA-100-3mg film.
    • fig. S14. Excitation wavelength–dependent photophysical properties of the PVA-100-3mg film.
    • fig. S15. Photophysical properties of G-doped different PVA matrix films.
    • fig. S16. Photophysical properties and molecular structures.
    • fig. S17. FTIR spectra, XRD patterns, and SEM images of the PVA-100-3mg film under different conditions.
    • fig. S18. Phosphorescence emission spectra of patterns for the lotus flower under different conditions.
    • fig. S19. Green screen printing procedures without using any inks.
    • table S1. Photophysical data of PVA films by doping different concentrations of G.
    • table S2. Photophysical data of the PVA-100-3mg film at different irradiation times under a 254-nm UV lamp.
    • table S3. Photophysical data of the PVA-100-3mg film at different temperatures.
    • table S4. Photophysical data of the PVA-100-3mg film at different excitation wavelengths under ambient conditions.
    • Legends for movies S1 to S4
    • Reference (38)

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.avi format). Appearance of the emitting G-doped PVA films when UV light is on and off.
    • movie S2 (.avi format). Appearance of the emitting PVA-100-3mg film when UV light is on and off.
    • movie S3 (.avi format). Imaging of the logo of the lotus flower.
    • movie S4 (.avi format). Imaging of the logo of the lotus flower containing AlQ3.

    Files in this Data Supplement:

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