Waterproof Flexible InP@ZnSeS Quantum Dot Light‐Emitting Diode
Dong‐Wook Shin, Yo‐Han Suh, Sanghyo Lee, Bo Hou, Soo Deok Han, Yuljae Cho, Xiang‐Bing Fan, Sang Yun Bang, Shijie Zhan, Jiajie Yang, Hyung Woo Choi, Sung‐Min Jung, Felix C. Mocanu, Hanleem Lee, Luigi G. Occhipinti, Young Tea Chun, Gehan Amaratunga, Jong Min Kim
Abstract
Abstract The development of flexible displays for wearable electronics applications has created demand for high‐performance quantum dot (QD) light‐emitting diodes (QLEDs) based on QD core@shell structures. Emerging indium phosphide (InP)‐based core@shell QDs show promise as lighting material in the field of optoelectronics because they are environmentally friendly material, can be produced in a cost‐effective manner, and are capable of tunable emission. While efforts have been made to enhance the performance of InP‐based QLED, the stabilities of InP@ZnSeS QDs film and InP@ZnSeS‐based QLED in water/air are not yet fully understood, limiting their practical applications. Herein, a highly durable, flexible InP@ZnSeS QLED encapsulated in an ultrathin film of CYTOP, a solution‐based amorphous fluoropolymer, is demonstrated. The CYTOP‐encapsulated green flexible QLED shows an external quantum efficiency (EQE) of 0.904% and a high luminescence of 1593 cd m −2 as well as outstanding waterproof performance. The flexible device emits strong luminescence after being immersed in water for ≈20 min. Even when subjected to continuous tensile stress with a 5 mm bending radius, the high luminescence is preserved. This waterproof architecture can be a promising strategy for wearable electronics applications.