The Fabrication Of High Performance Green And White Organic Light-Emitting Diodes

Phosphorescent materials have attracted much attention because both singlet and triplet excitons of them can be utilized to reach theoretically 100%internal quantum efficiency.In the past decades,many achievements have been made in the development of phosphorescent materials,but there are few studies on the design and fabrication of organic light-emitting diodes?OLEDs?.This paper focuses on the design and fabrication process of OLEDs,and highly efficient green and white devices were fabricated based on red,green,and blue phosphorescent materials.We have designed and fabricated a series of highly efficient devices by optimizing the concentrations of emitters and sensitizer and the thickness of functional layer based on green?Ir?mppy?₃?with the device structure of ITO/HAT-CN?6 nm?/HAT-CN?0.2wt%?:TAPC?50 nm?/Ir?ppz?₃?0.6 wt%?:Ir?mppy?₃?10 wt%?:TcTa?10 nm?/Tm3PyP26PyB?75 nm?/LiF?1 nm?/Al?100 nm?.Finally,the optimal green electroluminescent devices displayed the turn-on voltage,maximum brightness,external quantum efficiency,current efficiency,and power efficiency up to 2.8 V,121000 cd/m²,31.8%,111.0 cd/A and 101.60lm/W,respectively.A series of highly efficient devices were designed and fabricated by optimizing the concentrations of red emitter and device structure based on green?Ir?mppy?₃?,red??fbi?₂Ir?acac??and blue?FIrpic?iridium complexes with the structure of ITO/HAT-CN?6nm?/HAT-CN?0.2 wt%?:TAPC?50 nm?/?fbi?₂Ir?acac??2 wt%?:Ir?mppy?₃?10 wt%?:TcTa?7nm?/?fbi?₂Ir?acac??1.4 wt%?:FIrpic?18 wt%?:TcTa?3 nm?/FIrpic?18 wt%?:CzSi?8nm?/Tm3PyP26PyB?60 nm?/LiF?1 nm?/Al?100 nm?.Finally,the optimal white electroluminescent device displayed the turn-on voltage,maximum brightness,external quantum efficiency,current efficiency,and power efficiency up to 2.6 V,38150 cd/m²,16.8%,44.92 cd/A and 42.85 lm/W,respectively.In addition,the CIE of the white device is?0.337,0.458?Our experimental results demonstrated the sensitizer molecules function as deeper hole trappers and center of energy transfer,which help to balance the carriers'distribution and facilitate the energy transfer in the green phosphorescent OLEDs,thus further improved the performances of device.Highly efficient white OLEDs were fabricated by utilizing host materials with well-matched energy levels to improved carriers'balance and optimizing the doping concentration of red emitter and the structure of device to control the proportion of different light.