| Luminescent materials are widely used in the fields of medicine,biology,chemistry and so on.Luminescent is divided into fluorescence and phosphorescence.Phosphorescence materials have great potential in applications such as photovoltaic devices,bioimaging,photocatalytic organic reactions,photodynamic therapy due to their involvement of excited triplet states,comparatively long delay lifetimes and 100%theory internal quantum efficiency when applied in organic electroluminescent materials,therefore phosphorescence materials arised increasing attention.Phosphorescence materials include inorganic compounds and organic compounds.Organic materials have huge species and the structure is easier to control campared with inorganic materials,so researchers are more interested in organic materials.Based on the above considerations,we studied two systems of phosphorescence materials including one novel kind of gold isocyanicde complex and a series of pure oaganic room temperature phosphorescence(RTP)complexes.Details are as follows:Next,we designed and synthesizeda series of pure organic materials because the metal coordination phosphorescent compounds often need introduce precious metals,however the photophysical process of pure organic phosphorescent compound is easy to control.The conformation of crystallization induced hardening stiffness is conducive to build long lifetime of pure organic RTP materials;the introduction of the donor-acceptor(D-A)electronic structure can prompt intramolecular charge transfer,which can facilitate us to tune luminescenct color of mayerials;Carbazole is an intensively used planar electron donor with high triplet energy level,which is commonly used to construct RTP molecular materials;the introduction of aromatic carbonyl is an effective method to improve the efficiency of ISC.Based on the above considerations,we designed and synthesized CZBZ with D-A structure and their tertiary butyl substituted DtBuCZBZ and brominated IBCZBZ,PBCZBZ and BCZBZ.The results show that these five complexes simultaneously emit both fluorescence and phosphorescence in crystalline state at room temperature.CZBZ shows super persistent RTP property with the lifetime was 759 ms.Phosphorescence efficiency(Φ_P)of IBCZBZ,PBCZBZ and BCZBZ was improved due to the heavy atom effect,especially PBCZBZ(Φ_P=20.6%).To our surprise,IBCZBZ and PBCZBZ also possess super peresitent RTP property with the life time are 190 ms and 162 ms,which was rarely reported among heavy atom attached pure organic phosphorescence materials.DtBuCZBZ and BCZBZ prescent no super long life RTP due to their poor crystallinity.Upon external grinding,they show reversible mechanochromism behavior. |
