Design, Synthesis And Photoelectric Properties Of Phosphorescent Iridium(Ⅲ) Complexes With Pyridyl Triazolate Chromophors

The global environment pollution and energy shortage are an important factor inrestricting human survival and sustainable development. Developing clean, efficient andrecyclable new energy resoure, for example solar and hydrogen, reducing the waste ofresources and improving the energy utilization such as organic light-emitting diode (OLED)display and solid-state lighting devices with low driving voltage are the goal what have tocontinually pursue with technological advancements. How to achieve the targets which areefficiently prepare clean energy and high effiency electroluminescent devices and full-colordisplay have drawn tremendous research interest from both academia and industry. Transitionmetal complexes can efficiently utilize triplet exciton to achieve efficient phosphorescentemission through the highly efficient heavy-atom spin-orbitcoupling (SOC). Among thetransition metal complexes, iridium(III) complexes attract more attention in theelectroluminescent field, in which they exhibit high quantum yields, excellent optical andthermal-stabilities and full-color display. They are applied on a variety ofphotoelectrochemical field due to the fast SOC and the presence of high-lying metal-centeredligand-field state. These advantageous aspects of triplet-state iridium(III) complexes canwiden a variety of application on photonic, catalytic and biological fields.In this paper, we investigated two aspects of these photoelectric functional properties ofnovel iridium(III) comlexes. The relative research works are outline as follows:1. The blue light-emitting materials are essential to solid-state lighting and full colordisplay. We designed and synthesized two new greenish-blue emission iridium(III) complexesincluding high-field strength carbene ligands and high π-π*energy gap triazole-pyridine typeligand. Their photophysical, electrochemical and thermal properties were systematicallyinvestigated. The results show that the iridium(III) complexes possess good quantumefficiency efficiencies and excellent thermal stability. The theoretical calculations have alsobeen performed to ascertain the nature of their excited-states characters and rationalize thephotophysical and electrochemical properties. When these two complexes were doped intohost material POAPF, greenish-blue and white phosphorescent OLEDs with low turn-onvoltage and relatively high efficiencies have been successfully achieved. The maximumbrightness of greenish-blue device is3206cd m-2and the peak power efficiency11.43lm W-1.The white device utilizing two doped emitting layer has a maximum brightness of3910cdm-2, a peak power efficiency of9.95lm W-1with CIEx,yvalues of (0.34,0.40), which closesto ideal white light.2. The photosensitizer (PS) materials with strong visible absorption, relatively long excited-state lifetimes, good stability and a large driving force for intermolecular electrontransfer are very important to achieve good catalytic performance for photoinduced hydrogengeneration. We have designed and synthesized three water-soluble iridium(III) complexes byusing different C^N cyclometalating ligands and carboxyl contained triazole-pyridineancillary ligand with strong electron deficient character, and studied the relationship betweenstructre and properties of these iridium(III) complexes. Their photophyical, electrochemicaland surface photovoltage properties were investigated in detail. The results reveal that theyboth have large molar absorption coefficient, especially complex3exhibits extraordinaryabsorption performance in the visible region. Their reduction potential are about–1.0Vversus NHE, this provides a sufficient driving force for light driven hydrogen production. Thevisible-light-driven water splitting were carried out in different solution. The hydrogen wascollected in pure water. The complex3show good catalytic performance in CH3OH/H2O(1:1), with the amount of hydrogen of398μmol.