Enhanced-Evanescent-Field Induced Photoluminescence of Rubrene Thin Films

Abstract

Photoluminescence (PL) was investigated for rubrene thin films with thickness comparable to light wavelength on silver in attenuated total reflection (ATR) geometry. The ATR properties indicate excitations of ATR modes that differ from surface plasmon resonance (SPR) in the metal. The ATR modes enabled enhancement of the PL intensity by 42 times at the peak wavelength, compared with that on glass. This enhancement is attributable to an increase of absorption in rubrene layers induced by enhanced evanescent fields. ATR-mode excitation can provide enhanced fluorescence not only for fluorescent thin films < 100 nm, but also for thicker films.

Keywords:

• Photoluminescence
• fluorescence
• rubrene
• attenuated total reflection (ATR)
• evanescent field
• surface plasmon resonance (SPR)

Acknowledgments

The author thanks Mr. T. Kitami (Seishin Trading Co. Ltd.) for experimental support. This work was supported by the JSPS KAKENHI Grant.