Study on Performances for White Organic Light-emitting Device Based on Color Conversion Layer

A White Organic Light-Emitting Device(WOLED) was realized by combining dual-emission blue organic light-emitting device of ITO/NPB(30 nm)/mCP(5 nm)/mCP:Firpic(8%, 30 nm)/TPBi:Firpic (8%, 10 nm)/TmPyPB(30 nm)/Cs2CO3(1 nm)/Al with color conversion layer based on PMMA:DCJTB. Experimental results indicate that the current efficiency and Color Rendering Index(CRI) can be controlled by adjusting the concentration of DCJTB in color conversion layer. The maximum current efficiency, Commission Internationale de L'Eclairage(CIE) and CRI are 13.4 cd.A(-1), (0.33, 0.31) and 69, respectively, when the concentration of DCJTB is 1.0%. To further improve the device performances, TPBi/TPBi:Ir(ppy)(3) was inserted between the emission layer of TPBi:Firpic and the electron transport layer of TmPyPB. It is illustrated that the inserted structure can improve the CRI, increase the effective absorption of color conversion layer, and limit the recombination region of excitons to enhance the optoelectronic performances of the device. The maximum current efficiency, CIE and CRI for optimal WOLED reach 17.8 cd.A(-1), (0.35, 0.33) and 81, respectively.