Performance comparison of CuPc and 2T-NATA in organic light-emitting devices

Abstract

Using CuPc as the hole buffer material, the effect of 2T-NATA and CuPc as hole buffer materials in similar structure on the performance of devices is studied. For this reason, the ITO/CuPc (20 nm)/NPBX/DPVBi (20 nm) (15 nm)/Alq3: Rubrene (10, X nm)/Alq3 (40 nm)/LIF/Al (5 nm) light-emitting device is designed. Referring to the previous papers on similar structure devices, the best effect is that the thickness of doped rubrene is 20 nm. In this paper, the thickness of Alq3 doping is 10 nm, the thickness of rubrene is adjusted to 5 nm, 10 nm, 15 nm, 20 nm and 25 nm, and the buffer thickness of CuPc is selected at 20 nm according to the previous experimental results. The experimental results show that when the thickness of rubrene is 20 nm, the yellow light and blue light of the light-emitting materials tend to balance, and the device is close to the white light device. The brightness and efficiency of the device are the highest, reaching and 21050 cd/m2 5.527 cd/A respectively. Compared with 2T-NATA as the buffer material, its luminous efficiency and brightness are improved. Through the analysis of the experimental results, we find that CuPc as a hole buffer material reduces the hole carrier injection barrier, improves the hole injection ability, and enhances the recombination probability of hole and electron, improves the luminous efficiency and brightness of the device. It is concluded that 2T-NATA is more suitable than CuPc in the aspect of practical application and energy saving. The advantage of CuPc is that it can inhibit the diffusion of chemical components in ITO to the hole transport layer, which is beneficial to the improvement on device performance and life.