Flexible light-emitting diodes using organometal halide perovskite with ultrathin Au electrode

摘要

Recently, the solution-processable material organometal halide perovskites have attracted great attention for the properties of excellent charge carrier mobility, high photoluminescence quantum efficiency (PLQE) and the possibility of low-cost, scalable fabrication of lightweight and flexible devices [1]. In particular, the flexibility of the PLEDs becomes a very attractive feature and has potential applications in flexible devices. Indium tin oxide (ITO) is currently dominant transparent anode in PLEDs, due to its high optical transparency, high electrical conductivity and high work function [2]. However, ITO presents several drawbacks, such as the increasing cost of indium and its poor mechanical robust, which is unsuitable for applications in flexible devices [3]. In this work, we have demonstrated an efficient flexible PLEDs using an ultrathin Au electrode. As shown in Fig. 1, unlike ordinary Au electrodes that require a thickness of over 15nm to guarantee good film-reforming properties and high conductivity, only 7nm Au film was needed on SU8 photoresist film which showed lower roughness, and the conductivity (20 Ω) was comparable with ITO. Not only a more transparent anode was fabricated through this method, Furthermore, the perovskite crystallites can be achieved by a one-step method. The high quality perovskite films provide good light emission and the as-fabricated perovskite light-emitting devices have shown a maximum luminance of over 2000 cd/m2 as demonstrated in Fig. 2. Moreover, the PLEDs produced by our fabricating process have demonstrated good flexibility and device stability.