Organic light-emitting devices based on vacuum-deposited poly( p-phenylene) thin film

• Published in: Synthetic metals Vol. 114; no. 3; pp. 355 - 359
• Main Authors: Song, Won-Jun, Seoul, Chang, Kang, Gi-Wook, Lee, Changhee
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.09.2000; Amsterdam Elsevier Science; New York, NY
• Subjects: Application fields; Applied sciences; Electronics; Exact sciences and technology; Optoelectronic devices; Organic light-emitting device; Poly( p-phenylene); Polymer industry, paints, wood; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Technology of polymers; Vacuum deposition; Poly( p-phenylene); Organic light-emitting device; Vacuum deposition; Conjugated polymer; Voltage current curve; Electroluminescent device; Use; Photoluminescence; Phenylene polymer; Surface topography; Experimental study; Mechanism; Charge carrier injection
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(00)00269-1

Organic light-emitting device with poly( p-phenylene) (PPP) is prepared by vacuum deposition with various heating rates. The structure, morphology, photoluminescence (PL), electroluminescence (EL), and current ( I)–voltage ( V)–EL characteristics have been studied by IR spectroscopy, atomic force microscopy (AFM) and spectrofluorophotometer. The IR spectrum gave an evidence that the vacuum-deposited PPP (vd-PPP) chain involves 8–9 p-phenylene rings, which is known to be an effective conjugation length. The onset of the EL occurs at the electric field of about 7×10 7 V/m. I– V dependence fits very well with the Fowler–Nordheim (FN) tunneling formula. The results suggest that charge carrier injection is a tunneling process through an energy barrier of about 0.6–0.8 eV in ITO/PPP/Al devices.