Experiment with phosphorescent sheet

Phosphorescent sheet glows after lighting only by blue and UV light

Scientific name: Phosphorescence is initiated by light of specific spectrum

YouTube

The Chemistry of Light 25 - Phosphorescence

by Royal Society Of Chemistry

Phosphorescence vinyl sheet glows only with blue photons

by MrGrodskiChemistry

Writing in a phosphorescent sheet with homemade blu-ray laser

by LebrelZ

Phosphorescence

by manf1234

Safety

Don’t shine LEDs directly into eyes!

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

ZnS -[hv]→ ZnS* → ZnS + hv

Reagents

  1. Zinc sulfide

Step-by-step instruction

  1. Set a phosphorescent glow-in-the-dark vinyl sheet in a dark room.
  2. Shine a red LED on the sheet. There is no glowing.
  3. Shine a green LED. There is no detectible glowing or a little bit of glowing.
  4. Use a blue and violet (UV) LED the same way. There is a bright and longer visible glow in this case.

Scientific background

Phosphorescent glow-in-the-dark vinyl sheets contain ZnS doped Cu. For phosphorescence to arise, electrons of ZnS doped copper must be excited by sufficient energy. Photons of red (630 nm), orange (605 nm), yellow (592 nm) and green (525 nm) do not have sufficient energy to excite the electrons. But blue (470 nm), violet (405 nm) and UV (>400 nm) light photons can excite electrons. The greater the energy, the more intense is the glow. The maximum of absorption of light is 365 nm.

During phosphorescence conversion of the excited singlet state to a lower energy excited triplet state occurs. Then all excited electrons return to initial ground state and emit the light with a wavelength of 520 nm.

Danger:
Coolness:
Difficulty:

Published on 13 April 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst