Considerable improvement in the stability of solution processed small molecule OLED by annealing

• Published in: Applied surface science 2011-06, Vol.257 (17), p.7394-7398
• Main Authors: Mao, GuiLin, Wu, Zhaoxin, He, Qiang, Jiao, Bo, Xu, Guojin, Hou, Xun, Chen, Zhijian, Gong, Qihuang
• Format: Article
• Language: English
• Subjects: Annealing; Applied sciences; Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Cross-disciplinary physics: materials science; rheology; Density; Devices; Electronics; Equivalence; Exact sciences and technology; Light-emitting devices; Light-emitting diodes; Materials science; Optoelectronic devices; Organic light emitting diodes; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solution processed; Spin coating; Stability; Surface roughness; Treatment of materials and its effects on microstructure and properties
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.02.046

► We studied the annealing effect on solution processed small molecule organic films. ► The densities of the spin-coated films increased as the annealing temperature rose. ► The surface roughness decreased as the annealing temperature rose. ► Corresponding wet OLEDs’ stabilities are equivalent to the vacuum counterparts. ► Annealing process plays a key role in prolonging the stability of spin-coated OLED. We investigated the annealing effect on solution processed small organic molecule organic films, which were annealed with various conditions. It was found that the densities of the spin-coated (SC) films increased and the surface roughness decreased as the annealing temperature rose. We fabricated corresponding organic light emitting diodes (OLEDs) by spin coating on the same annealing conditions. The solution processed OLEDs show the considerable efficiency and stability, which were prior or equivalent to the vacuum-deposited (VD) counterparts. Our research shows that annealing process plays a key role in prolonging the lifetime of solution processed small molecule OLEDs, and the mechanism for the improvement of the device performance upon annealing was also discussed.