Buffer-enhanced electron injection in organic light-emitting devices with copper cathode

Role of Thick‐Lithium Fluoride Layer in Energy Level Alignment at Organic/Metal Interface: Unifying Effect on High Metallic Work Functions

“…However, for many other metals, especially those with high WF, LiF layer of such a thickness range (<1 nm) does not work well . Recently, it has been found that for OLEDs with high WF metals as cathodes, such as the noble metals Ag and Au as well as nonnoble metal Cu (together called coinage metals), a thicker LiF buffer layer can however significantly improve the electron injection and thus the device performance . Intriguingly, the optimal thickness of LiF buffer layer is nearly the same for the three coinage metal cathodes, ≈3 nm.…”

The effect of Indium metal nanoparticles on the electronic properties of organic light emitting diodes (OLEDs)

“…Since, the thickness of emissive layer was fixed so thickness variation did not have any broadening effect. A specific amount of metal nanostructure can enhance E-field effect [11,[25][26][27][28][29][30][31]. If the polymer molecules are in the vicinity of the metal NPs, the ground state to excited state transition probability can be increased.…”

“…Experimentally, it is found that OLEDs with high work function such as Au or Cu with specific amount of NPs (it depends on organic materials and fabrication process) can achieve nearly the same turn-on voltage and current density in comparison with low work function such as Ag. But in working voltage the differences are in low intensity and El for high work function OLEDs [25][26][27][28][29][30]. Indeed, it is believed that light scattering and light absorption of In NPs thin layer, decreases the efficiency of OLED [35].…”

Effects of Low Workfunction Metal Acetate Layers on the Electroluminescent Characteristics of Organic Light-Emitting Diodes

“…LiF가 전자주입 및 소자 특성에 미치는 메커니즘에 대해서는 tunneling barrier reduction [4], chemical reaction [5][6][7], dipole formation [8] 등 여러 가지 모델로 설명하고 있으며 최근까지도 LiF 박막의 OLED 소자특성 향상 메커니즘에 관한 연구결과가 발표되고 있다 [9]. 이 밖에도 Al 전극과 유기층의 계면에 metal fluorides(LiF [3], NaF [10], CsF [11]), metal oxides(MgO [12], Al 2 O 3 [13]), organic metal complexes (Ca(acac) 2 [14], NaSt [15] …”