School of Materials Science and Engineering , UNIST (Ulsan National Institute of Science and Technology) , Ulsan 44919 , Republic of Korea.
Low Dimensional Carbon Center , UNIST (Ulsan National Institute of Science and Technology) , Ulsan 44919 , Republic of Korea.
Nano Lett. 2019 Feb 13;19(2):971-976. doi: 10.1021/acs.nanolett.8b04200. Epub 2019 Jan 14.
Organic-inorganic hybrid perovskites have been investigated extensively for use in perovskite-based solar cells and light-emitting diodes (LEDs) because of their excellent electrical and optical properties. Although the flexibility of perovskite LEDs has been studied through empirical methods such as cyclic bending tests, the flexibility of the perovskite layer has not been investigated systemically. Here, flexible and semitransparent perovskite LEDs are fabricated: a PEDOT:PSS anode and Ag nanowire cathode allow for flexible and semitransparent devices, while the use of a conjugated polyelectrolyte as an interfacial layer reduces the electron injection barrier between the cathode and the electron transport layer (SPW-111), resulting in enhanced device efficiency. Cyclic bending tests performed on the electrodes and in situ hole-nanoindentation tests performed on the constituent materials suggest that mechanical failure occurs in the perovskite MAPbBr layer during cyclic bending, leading to a decrease in the luminance. Tensile properties of the MAPbBr layer explain the critical bending radius ( r) of the perovskite LEDs on the order of 1 mm.
有机-无机杂化钙钛矿因其优异的光电性能而被广泛用于钙钛矿基太阳能电池和发光二极管（LED）。尽管通过循环弯曲测试等经验方法已经研究了钙钛矿 LED 的柔韧性，但尚未系统地研究钙钛矿层的柔韧性。在这里，制备了柔性半透明钙钛矿 LED：PEDOT:PSS 阳极和 Ag 纳米线阴极允许制备柔性半透明器件，而使用共轭聚合物电解质作为界面层可以降低阴极和电子传输层（SPW-111）之间的电子注入势垒，从而提高器件效率。对电极进行的循环弯曲测试和对组成材料进行的原位空穴压痕测试表明，在循环弯曲过程中，机械失效发生在钙钛矿 MAPbBr 层中，导致亮度降低。MAPbBr 层的拉伸性能解释了钙钛矿 LED 的临界弯曲半径（r）约为 1mm。
