title: Controlled fabrication and optoelectrical properties of metallosupramolecular films based on ruthenium(II) phthalocyanines and 4,4'-bipyridine covalently anchored on inorganic substrates.
abstract: Fully conjugated metallosupramolecular self-assembled multilayer films were controllably fabricated based on bibenzonitril-phthalocyaninato ruthenium(II) (BBPR) and 4,4'-bipyridine (BP) via axially coordination interaction between ruthenium ions and the pyridine groups on the modified substrates. The substrates were first functionalized by 4-(pyridine-4-ylethynyl)benzenic diazonium salt (PBD) through photodecomposition of diazonium group under UV irradiation. As a result, the pyridine-containing functional groups were vertically and covalently anchored onto the surface of substrate and got a stable monolayer. Soluble ruthenium phthalocyanine, axially coordinated by labile benzonitrile groups, was used to fabricate the layer-by-layer self-assembled films with BP through ligand-exchanging reaction between benzonitrile and pyridine in each self-assembled cycle. The UV-vis analysis results demonstrated the successful fabrication of bi(4,4'-bipyridine)phthalocyaninato ruthenium(II) (BPPR) metallosupramolecular ultrathin films with definite structures on PBD-modified substrate. Under illumination, the BPPR self-assembled multilayer films displayed a quick response to light. The maximum current density reached 120 nA/cm(2) at six bilayers. The Eg, HOMO, and LUMO of the six-bilayer were quantitatively measured to be 1.68, -5.29, and -3.61 eV, respectively. This strategy supplies a facile method to get full-conjugated metallosupramolecules and a platform for developing higher performance solar cell from the point of adjusting dye aggregate state structure.
authors.affiliation: College of Materials Science and Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China. tongbin@bit.edu.cn
authors.forename: Bin
authors.initials: B
authors.lastname: Tong
authors.forename: Huanfang
authors.initials: H
authors.lastname: Yang
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Xiong
authors.forename: Fei
authors.initials: F
authors.lastname: Xie
authors.forename: Jianbing
authors.initials: J
authors.lastname: Shi
authors.forename: Junge
authors.initials: J
authors.lastname: Zhi
authors.forename: Wai Kin
authors.initials: WK
authors.lastname: Chan
authors.forename: Yuping
authors.initials: Y
authors.lastname: Dong