Excitons in crystalline thin films of 3,4,9,10-perylenetetracarboxylic dianhydride studied by photocurrent response

✍ Scribed by V. Bulović; S.R. Forrest

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 454 KB
• Volume: 238
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(95)00378-9

✦ Synopsis

We study excitons in crystalline thin fiims of the archetype molecular compound: 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) by measuring the photocurrent response under small electric fields (< lo4 V/cm). A previously uncharacterized exciton at a wavelength of A = 590 nm, or at 2.10 eV above the PTCDA highest occupied molecular orbital, is identified. Lower in energy than either of the previously observed charge transfer excitons at A = 475 and 555 nm in PTCDA, the A = 590 nm exciton is speculated to be Frenkel-like. The diffusion length of this exciton is 225 k 15 nm, compared to 88 f 6 nm for excitons generated between 475 and 555 nm.