Preparation of Polyperinaphthalene Thin Films by Excimer Laser Ablation and Their Application to Optic and Electronic Devices.

Abstract

Polyperinaphthalene (PPN) thin films are prepared by excimer laser ablation (ELA) of a 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) target or a mixture target of PTCDA with Co or TiO2 powder (PTCDA/X: X=Co, TiO2) using XeCl excimer laser beams. Enhancement of elimination reaction of side groups of PTCDA is observed by ELA of PTCDA/Co and PTCDA/TiO2. In particular, for PTCDA/TiO2, the reaction occurs at a fluence of 0.25Jcm-2pulse-1much lower than the case of PTCDA/Co at room temperature. Heterojunctions of PPN films prepared by ELA of PTCDA with Si wafers are fabricated. Well rectifier property is obtained for the junction of the PPN with a n-Si substrate. Current versus voltage curves of the heterojunction in the dark and under illumination show that the junction is promisimg as a photovoltaic cell. Furthermore, PPN films are applied to anode electrodes for ultra thin rechargeable Li ion batteries. Substrate temperature dependence ofeffective capacitance of lithium ions at first cycle are investigated. In addition, in-situ Raman spectroscopy of the films under lithium ion doping and undoping is performed to elucidate the storage mechanism of lithium ion at cis-polyacetylene-type edge (phenanthrene-edge) of PPN structure.