Synthesis And Properties Of Single-molecule White Emitters From Cyclometalated Iridium Complexes By Appending A Rocking Phenothiazine Unit

According to the different luminescence mechanism,in this master's thesis,organic single-molecule white emitters?OSMWEs?were classified briefly.At the same time,the research progress of white organic light emitting materials in recent years were described simply.To address the key issues of little single-molecular white-emitting materials,unsatisfied device efficiency,short service life and unstable luminescent chromaticity,we plan to investigate the phenothiazine-modified cyclometalated iridium complexes-based single-molecular white-emitting materials and their application in devices.As an electronic donor of the functional phenothiazine?PTZ?unit,multiple emissions from both the charge transfer?CT?and locally excited?LE?state might be generated for PTZ based pseudo-planar conformation luminophores.For this purpose,we have designed and synthesized three chapters of experimental contents to study the main relationship between structure and luminescence performance.The main details and results of this thesis are as follows:?1?A class of cyclometalated iridium complexes of?dfppyPTZ?₂IrPic,?dfppyPTZ?₂Ir?pytz?and?dfppyPTZ?₂IrPOP by appending a rocking electron-donating unit of phenothiazine were designed and synthesized.We expect to gain both the charge transfer?CT?and locally excited?LE?state from functional pseudo-planar structure of phenothiazine?PTZ?substituents.To gain molecular configuration and electron cloud distribution,the time-dependent density functional theory?TD-DFT?calculations were performed.As a result,only complex?dfppyPTZ?₂IrPic show the similar multiple emissions in THF solvent and warm white light emission with CIE color coordinate of?0.38,0.49?can be realized?2?Cyclometalated iridium complexes of?dfpypyPTZ?₂IrPic,?dfpypyPTZ?₂Ir?pytz?and?dfpypyPTZ?₂Ir?pz?₂B?pz?₂)were designed and synthesized.The effects of phenothiazine structure,introduction of nitrogen atom and ancillary ligand on the photophysical properties of cyclometalated iridium complexes were studied.Through TD-DFT calculations,we found that the part of phenothiazine unit involved in orbital hybridization were increased,which was also consistent with the phenomenon of wide spectral emission of solid films.When concentration of?dfpypyPTZ?₂Ir?pytz?doped in non-polar polystyrene?PS?matrix is15%,white light emission with CIE color coordinate of?0.29,0.36?can be realized.?3?Three cyclometalated iridium complexes were modified by phenothiazine unit,namely?dfppy?2Ir?PTZPic?,?dfppyPTZ?2Ir?PTZPic?and?dfpypyPTZ?₂Ir?PTZPic?,were designed and synthesized.By theoretical calculation,we found that the complex?dfppy?₂Ir?PTZPic?which was only modified the ancillary ligand,did not distribute electron cloud density in phenothiazine unit.As a result,a weak broad emission band around 450 nm could be observed only for?dfppyPTZ?₂Ir?PTZPic?and?dfpypyPTZ?₂Ir?PTZPic?.To our delight,?dfpypyPTZ?₂Ir?PTZPic?was the sole compound to display warm white-light emission with a CIE coordinate?0.33,0.45?because of the balanced the charge transfer?CT?and locally excited?LE?state.