Chuthatai Phanthawonge. Photoluminescence of dispersed zinc oxide nanoparticles in polymide films . Master's Degree(Chemical Engineering). Chulalongkorn University. Center of Academic Resources. : Chulalongkorn University, 2006.
Photoluminescence of dispersed zinc oxide nanoparticles in polymide films
Abstract:
This research aims to study the morphology, thermal stability and photoluminescence of zinc oxide (ZnO) nanoparticles in polyimide (PI) films. ZnO nanoparticles dispersed in PI films were prepared by adding zinc compounds or ZnO nanoparticles in poly (amic acid) (PAA) solution followed by thermal curing process to convert poly (amic acid) to PI under nitrogen or argon atmosphere. Zinc compounds which were zinc nitrate hexahydrate, were converted to ZnO by thermal decomposition while PAA was imidized. The presence of ZnO was confirmed by x-ray diffraction technique. The light emission of PI films containing ZnO from either thermal decomposition of zinc nitrate or ZnO added into PI directly was much higher than pure PI films because of high quantum efficiency. When zinc oxide concentration exceeded the saturation level, light emission decreased due to the aggregation of ZnO. The films in which ZnO was added directly exhibited higher intensity than PI films because of high quantum efficiency. When zinc oxide concentration exceeded the saturation level light emission decreased due to the aggregation of ZnO. The films in which ZnO was added directly exhibited higher intensity than PI films containing ZnO converted from zinc nitrate hexahydrate at the same concentration. In addition the light emission of all samples, which was prepared under nitrogen atmosphere, emitted higher intensity than those with argon atmosphere. However, the effect of curing temperature slightly affected the light emission intensity. The film containing directly added ZnO was more thermal stable than those containing ZnO from thermal decomposition of zinc nitrate hexahydrate. ZnO nanoparticles, which average size was 17-90 nm, were well distributed but poor dispersed in PI films.