Theoretical And Experimental Study Of Blue-green And Orange Organic Electroluminescent Materials

The organic electroluminescent material Ir（Ⅲ）complex,after decades of vigorous development,has received sufficient attention in various fields,especially in organic flat panel displays and large-area solid-state lighting has an impossible replacement role.However,blue and green materials do not seem to meet many industrial application standards.They have a wider band gap than red materials,and their emission efficiency decreases accordingly.In addition,due to the high-efficiency roll-off characteristics of existing organic electroluminescent materials,most of the Ir（Ⅲ）complexes emitting blue and green light cannot satisfy industrial applications in the OLED field.At the same time,in the medical field,in order to protect human health,it is recommended to use low color temperature light sources at night,such as candlelight（orange）.However,the effective orange color of Ir（Ⅲ）complex（color temperature below2000k）is very limited,and the efficiency roll-off of Ir（Ⅲ）complex by this light source is also worthy of attention.Therefore,it is urgently needed to find blue and green Ir and orange-yellow light（Ⅲ）complexes with relatively good properties and industrial indicators that can meet industrial specifications.In this paper,we use the Ir（mpim）₃ and the orange（ptpy）₂Ir（acac）Ir（Ⅲ）complexes that have been proven to be highly efficient blue as the structural reference,using density functional theory（DFT）and Time-density functional theory（TDDFT）method theoretically designed a series of blue and green Ir（Ⅲ）complexes:Ir（F-mpim）₃,Ir（F₂-mpim）₃,（mpim）₂Ir（acac）,（F-mpim）₂Ir（acac）,（F₂-mpim）₂Ir（acac）,（mpim）₂Ir（tpip）,（F-mpim）₂Ir（tpip）,（F₂-mpim）₂Ir（tpip）and a series of Orange-yellow Ir（Ⅲ）complex with low"efficiency roll-off"performance and low color temperature:（ptpy）₂Ir（tpip）,（F-ptpy）₂Ir（acac）,（F-ptpy）₂Ir（tpip）,（F₂-ptpy）₂Ir（acac）and（F₂-ptpy）₂Ir（tpip）.The molecular structure,absorption spectrum,emission spectrum and front-line molecular orbital properties of the above complexes were calculated and analyzed.The calculation methods are DFT/B3LYP and TDDFT/B3LYP.In all calculations,the LANL2DZ group is used for metal atoms Calculation of Ir,6-311+G*basis set is used for calculation of C,H,N,O,P and F atoms.Through the analysis and discussion of the calculation results,the research object has low"efficiency roll-off"and low color temperature characteristics,and also found that the complex analyzed in this article is very suitable for use in the field of OLED.