Construction Of Optoelectronic Functional Materials Based On 5,10-diphosphine Heteroanthracene Structur

In this paper,the organic photoelectric functional materials based on5,10-dihydrophosphanthrene structure were introduced,and the photoelectric properties of the molecular materials were investigated at the same time.Their basic physical characterization were measured and the related applications were carried out.Due to the high triplet energy level for molecule 5,10-diphenyl-phosphanthrene（DPDPA）,it could be utilized as the host material to fabricate blue electroluminescent device after vulcanization or oxidation to realize directional regulation of molecular configuration.In which,the phosphine oxide group will form intramolecular hydrogen bonds with adjacent hydrogen atoms,so that diphosphine oxide compound keep the stable boat conformation,its molecular configuration is spherical,the molecular packing form is tightly packed,and which afford the molecule5,10-diphenyl-phosphanthrene 5,10-dioxide（DPDPO₂A）good carrier injection and transporation ability.When utilize it as the host to fabricate the electroluminescent device,which achieve the current reference reported the minimum turn-on voltage of2.5 V for blue thermally activated delayed fluorescence（TADF）electroluminescent device,with the high external quantum efficiency of 22.5%.The result suggest that the control of the host material molecular configuration,and thus affecting its accumulation,which can provide a feasible solution for solving the contradiction between suppressing the intermolecular interaction and improving the carrier injection and transportation balance in the emitter layer.For DPDPA,A new type of photochromic and thermochromic materials based on the P-atom with Inversion of configuration.Both the solid powder and its doped polymethyl methacrylate（PMMA）film showed good photochromic property,change the color from white to red under ultra violet irradiation.The quantitative calculations suggest that the color changed process was owe to the change that chair conformation and the boat conformation of theπ-πinteraction between the phenyl on 5,10 position.This process has a significant dependence on the excitation wavelength.Meanwhile,it can be found that external heating can accelerate the fading process of the material,and which also shows a significant temperature dependence.The blue TADF guest material was constructed with DPDPO₂A as the electron acceptor carbazole group as the electron donor synthesized the molecule 2,3,7,8-tetracarbazolyl-5,10-diphenyl-phosphanthrene 5,10-dioxide（4CzDPDPO₂A）.In which DPDPO₂A as the electron acceptor with larger conjugated area compared to the phosphine oxide group,and stronger electron-withdraing inductive effects.On the one hand,the electrons with push-pull effect can be increased,on the other hand the configuration of the molecule could be more twist,and the both can lead to the significant separation for frontier orbital affording the molecule small singlet-triplet energy gap(ΔE_ST).Compared with the open-loop structure molecule,the molecule4CzDPDPO₂A whose fluorescence spectrum emission peak showed a red shift,which indicating that the molecule has a stronger charge transfer property.At the same time,itsΔE_STvalue is smaller and the decomposition temperature is higher,which proves that the phosphine contained heterocyclic ring molecule can be expected to construct a highly efficient new type of guest material for thermally activated delayed fluorescence device.