Polymer light-emitting diodes with a phenyleneethynylene derivative as a novel hole blocking layer for efficiency enhancements

• Published in: Synthetic metals 2006-05, Vol.156 (9), p.690-694
• Main Authors: Wantz, G., Dautel, O., Vignau, L., Serein-Spirau, F., Lère-Porte, J.P., Hirsch, L., Moreau, J.J.E., Parneix, J.P.
• Format: Article
• Language: English
• Subjects: Application fields; Applied sciences; Chemical Sciences; Electronics; Exact sciences and technology; Optoelectronic devices; or physical chemistry; Organic chemistry; Polymer industry, paints, wood; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Technology of polymers; Theoretical and
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2006.03.007

This paper reports on the use of an electron transport layer (ETL) in polymer light-emitting diodes based on poly(2,5-bis(3′,7′-dimethyl-octyloxy)1,4-phenylene-vinylene) (BDMO-PPV). This ETL is inserted between BDMO-PPV and a calcium cathode as a hole blocking layer (HBL). A novel phenyleneethynylene derivative (ImPE) is proposed and compared to well-known materials such as tris(8-hydroxyquinoline) aluminum (Alq 3) and bathocuproïne (BCP). Efficient hole blocking is achieved leading to yield improvements at low luminances. With a 8 nm-thick ImPE layer, at 1 cd/m 2, the power efficiency reaches 1.2 lm/W whereas a BDMO-PPV-only PLED exhibits a 0.13 lm/W power efficiency. ImPE enables to reach higher performances than Alq 3 for low luminances (