TBPe Based Organic Electroluminescence Devices

TBPe is a well known small molecule dopant and efficient blue fluorescent material. The performance of the MEH-PPV devices can be improved by doping TBPe. Multilayer structure can effectively reduce the electrode quenching and improve the performance of the electroluminescent devices. Using TBPe in reasonable collocation with other red light and green light material, we can design the preparation of white organic light emitting device in simple structure.The device characteristics of MEH-PPV (poly [2-methxy-5-(2-ethylhexylxy)-1,4-phenylenevinylene]) doped with TBPe (2,5,8,11-tetratertbutylperylene) is investigated. The best highest efficiency was obtained in the device with the structure of ITO/PEDOT:PSS/MEH-PPV/TBPe (0.5nm)/Al whose luminous intensity increased by325%compared with the standard device and ITO/PEDOT:PSS/MEH-PPV: TBPe (100:30in wt.)/Liq/Al whose luminous intensity increased by44%compared with not doping TBPe device, and the580nm peak was in EL spectra of all devices. To enhance the electrons injection, the EIL (electron injection layer) of Alq3and the bufferlayer of Liq and LiF was employed. The multi-layer OLED (organic light emitting device) was made with the structure of ITO/PEDOT:PSS/MEH-PPV:TBPe/TBPe/Alq3/LiF/Al and ITO/PEDOT:PSS/MEH-PPV:TBPe/TBPe/Alq3/LiF/Al. The brightness of OLED with multi-layer structure and modified layer of Liq and LiF could reach to4162.2cd/m2and4701cd/m2respectively.Two different experimental methods were applied to make two various white light emitting devices. The first method uses the coevaporation of TBPe and Rubrene to make white OLED device. The structure of the device is ITO/NPB (50nm)/TBPe: Rubrene (40nm, Rwt=1%)/Alq3(40nm)/LiF (0.5nm)/Al (100nm).When the voltage is4V, the white OLED device turns on. The maximum luminous brightness is2234cd/m2at the voltage of9V, while the white OLED device’s color coordinate is (0.3317,0.3401),which locates in the center of the white area. The second method is spin coating, which realizes the white light emission. The structure of the device is ITO/PVK:TBPe (wt%=95:5,10mg/ml)/Alq3:Rubrene (40nm, Rwt%=1%)/LiF (0.5nm)/Al (100nm). The device turns on when the applied voltage is4V. The maximum brightness is5185cd/m2at the voltage of12.2V, while the white OLED device’s color coordinate is (0.3411,0.3874). With increasing voltage, the brightness of the device enhances, the white OLED device’s color coordinate locates in the above center of the white area.