title: Systematic investigation of surface modification by organosiloxane self-assembled on indium-tin oxide for improved hole injection in organic light-emitting diodes.
abstract: Various works on modification of the indium-tin oxide (ITO) substrate have been carried out so as to enhance hole injection in organic light-emitting devices. Herein, a simple and efficient approach to tuning the work function of the ITO substrate is described by surface modification of ITO with an organosiloxane self-assembled monolayer. The influences of the electronegativity on modification of the ITO substrate are systematically investigated by attaching electron-withdrawing groups (Cl, Br, and I) and an electron-donating group (NH2) to the organosiloxane materials. The preparation and modification of the ITO substrate has been studied using primarily atomic force microscopy and X-ray photoelectron spectroscopy and vacuum-ultraviolet spectroscopy, and remarkable changes have been observed after modification. The device based on a 3Cl-Si-ITO-modified anode exhibits the best efficiency among the devices, better than the control devices based on bare ITO, UV-treated ITO, and even Cl-ITO.
authors.affiliation: Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Lian
authors.initials: L
authors.lastname: Duan
authors.forename: Deqiang
authors.initials: D
authors.lastname: Zhang
authors.forename: Guifang
authors.initials: G
authors.lastname: Dong
authors.forename: Juan
authors.initials: J
authors.lastname: Qiao
authors.forename: Liduo
authors.initials: L
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu