Effect of swift heavy ion irradiation on photoluminescence of Tris-(8-hydroxyquinoline)aluminum thin films

✍ Scribed by K. Thangaraju; R. Kumaran; K. Asokan; P. Ramamoorthy; D. Kanjilal; J. Kumar

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 376 KB
• Volume: 203
• Category: Article
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2009.02.093

✦ Synopsis

We report the effect of swift heavy ions (SHI) of 40 MeV Li 3+ ions on Tris-(8-hydraxyquinoline) aluminum (Alq 3 ) thin films deposited by thermal evaporation process on glass substrates. To understand the effect of the temperature-dependent optical properties, these thin films were irradiated both at 300 K and ~77 K and were characterized by photoluminescence (PL), Infrared (IR) and time resolved photoluminescence (TRPL) spectroscopy. The PL and lifetime of SHI irradiated both at 300 K and ~77 K Alq 3 thin films were found to decrease with ion fluences compared to as-deposited Alq 3 thin films. This is due to the quenching of excitons by the defects created by SHI irradiation. The significant decrease in PL and lifetime of SHI irradiated (~77 K) Alq 3 thin films is attributed to the increased defect density, caused by the frozen charge carriers and poor molecular overlap resulting in weak bonding between Alq 3 molecules at low temperature.