Zhou Huanyu, Han Shin Jung, Lee Hyeon-Dong, Zhang Danzhen, Anayee Mark, Jo Seung Hyeon, Gogotsi Yury, Lee Tae-Woo
Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
A.J. Drexel Nanomaterials Institute and Department of Materials Science and Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA.
Adv Mater. 2022 Oct;34(41):e2206377. doi: 10.1002/adma.202206377. Epub 2022 Sep 14.
MXenes constitute a rapidly growing family of 2D materials that are promising for optoelectronic applications because of numerous attractive properties, including high electrical conductivity. However, the most widely used titanium carbide (Ti C T ) MXene transparent conductive electrode exhibits insufficient environmental stability and work function (WF), which impede practical applications Ti C T electrodes in solution-processed optoelectronics. Herein, Ti C T MXene film with a compact structure and a perfluorosulfonic acid (PFSA) barrier layer is presented as a promising electrode for organic light-emitting diodes (OLEDs). The electrode shows excellent environmental stability, high WF of 5.84 eV, and low sheet resistance R of 97.4 Ω sq . The compact Ti C T structure after thermal annealing resists intercalation of moisture and environmental contaminants. In addition, the PFSA surface modification passivates interflake defects and modulates the WF. Thus, changes in the WF and R are negligible even after 22 days of exposure to ambient air. The Ti C T MXene is applied for large-area, 10 × 10 passive matrix flexible OLEDs on substrates measuring 6 × 6 cm. This work provides a simple but efficient strategy to overcome both the limited environmental stability and low WF of MXene electrodes for solution-processable optoelectronics.
MXenes是一类快速发展的二维材料家族，因其具有众多吸引人的特性（包括高导电性），在光电子应用方面颇具潜力。然而，最广泛使用的碳化钛（TiCT）MXene透明导电电极表现出不足的环境稳定性和功函数（WF），这阻碍了其在溶液处理光电子学中TiCT电极的实际应用。在此，具有致密结构和全氟磺酸（PFSA）阻挡层的TiCT MXene薄膜被提出作为有机发光二极管（OLED）的一种有前景的电极。该电极表现出优异的环境稳定性、5.84 eV的高功函数以及97.4 Ω/sq的低方块电阻R。热退火后的致密TiCT结构可抵抗水分和环境污染物的嵌入。此外，PFSA表面改性钝化了片间缺陷并调节了功函数。因此，即使在暴露于环境空气中22天后，功函数和R的变化也可忽略不计。TiCT MXene被应用于尺寸为6×6 cm的基板上的大面积10×10无源矩阵柔性OLED。这项工作提供了一种简单而有效的策略，以克服MXene电极在溶液可加工光电子学中环境稳定性有限和功函数低的问题。
