Origin of charge generation efficiency of metal oxide p-dopants in organic semiconductors

✍ Scribed by Jae-Hyun Lee; Hyun-Mi Kim; Ki-Bum Kim; Jang-Joo Kim

• Book ID: 104076182
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 907 KB
• Volume: 12
• Category: Article
• ISSN: 1566-1199
• DOI: 10.1016/j.orgel.2011.03.008

✦ Synopsis

We report that the low charge generation efficiency of metal oxide dopants in organic semiconductor hosts is originated from the formation of dopant nanoclusters. Dopant nanoclusters of rhenium oxide (ReO 3 ) and molybdenum oxide (MoO 3 ) exhibit log-normal size distributions with an average radius of 0.7-1.4 nm and standard deviation of 1.5-2.6 nm, depending on the dopant and their concentration in 1,4-bis[N-(1-naphthyl)-N 0 -phenylamino]-4,4 0 diamine (NPB). The number ratio of the nanoclusters to dopant molecules (dispersion efficiency) was measured to be 0.62-1.3% for the ReO 3 -doped NPB. The low dispersion efficiency is close to the charge generation efficiency of 0.7-1.1%, which is defined as the ratio of generated carriers to dopant molecules, indicating that charge generation efficiency in the dopants is predominantly controlled by the dispersion of dopants in organic semiconductors.