Investigation Of OLEDs Based On Novel Exciplex With Different Donors

Organic light-emitting device?OLED?is considered as the most promising emitting devices and because of the incomparable advantages of light weight,low energy consumption,high contrast ratio,flexible lighting compared with other traditional light emitting devices,it has been widely used in flat-panel displays and solid-state lighting.The research of traditional OLED is confined to improve the performance of device and reduce the cost of device fabrication and rarely consider the turn-on voltage,device structure and spectral stability,seriously restricting the development of OLED industry.In order to solve these problems,a series of low turn-on voltage,simple structure,and stable spectral OLEDs were successfully prepared in this paper.The main contents are as follows:1.Red OLEDs based on Tris-PCz:B4Py PPM exciplex system were investigated.Hole transporting material Tris-PCz and electron transporting material B4Py PPM were respectively donor and acceptor materials to get yellow-green OLED.By analyzing the photoluminescence spectra and triplet energy levels of the exciplex system,it was found that the exciplex system could meet the requirements of doping red fluorescent materials and phosphorescent materials respectively.In the experiment,1:1 molar ratio of Tris-PCz and B4Py PPM has been used,which shows excellent host properties in red fluorescent and phosphorescent devices.The turn-on voltage of the red fluorescent phosphor DCJTB device is 2.3 V and the external quantum efficiency is 9.3%.The turn-on voltage of the red phosphorescent phosphor Ir?MDQ?₂acac device is 2.3 V and the external quantum efficiency is 20.3%.2.Monochromatic light OLEDs based on m-CBP:B4Py PPM exciplex system were investigated.The hole-transporting material m-CBP and the electron-transporting material B4Py PPM were selected as the donor and acceptor materials,respectively.We mixed them with 1:1 molar ratio as the phosphorescent body and the main body showed a dark blue photoluminescence spectrum.Then,four kinds of phosphorescent materials,such as FIrpic,F₃Irpic,Ir?ppy?₂acac and Ir?MDQ?₂acac,were doped in the host to construct blue,blue,green,green and red ldevices with simple structure.The maximum external quantum efficiencies were 20.1%,20.0%,22.3%and 21.9%,respectively,for the four devices.3.White OLEDs based on m-CBP:B4Py PPM exciplex system were further investigated.Two kinds of white OLEDs with simple structure and stable spectrum were prepared by mixing the phosphorescent materials in the host.The turn-on voltage of the white device doped with Firpic and Ir?MDQ?₂acac was 2.5 V,and the maximum external quantum efficiency is 18.2%;the turn-on voltage of the white device doped with F₃Irpic and Ir?MDQ?₂acac is 2.5 V and the maximum external quantum efficiency is 21.0%.In this paper,a series of high efficiency devices based on novel exciplex composites were successfully prepared,which provided a scheme for the design and construction of the devices,thus promoting the development of OLED in the field of red and white light.