Scalable All‐Evaporation Fabrication of Efficient Light‐Emitting Diodes with Hybrid 2D–3D Perovskite Nanostructures

• Published in: Advanced functional materials 2020-09, Vol.30 (39), p.n/a
• Main Authors: Fu, Yu, Zhang, Qianpeng, Zhang, Daquan, Tang, Yunqi, Shu, Lei, Zhu, Yiyi, Fan, Zhiyong
• Format: Article
• Language: English
• Subjects: all‐evaporation process; Diffusion rate; Evaporation; hybrid 2D–3D structures; Lead compounds; light emitting‐diodes; Materials science; Metal halides; Morphology; nanostructures; Perovskites; Physical vapor deposition; Quantum efficiency; Service life assessment; Thickness; Thin films
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202002913

Quasi‐2D (Q2D) lead halide perovskites have emerged as promising materials for light‐emitting diodes (LEDs) due to their tunable emission, slowed‐down carrier diffusion, and improved stability. However, they are primarily fabricated through solution methods, which hinders its large‐scale manufacture and practical applications. Physical‐vapor‐deposition (PVD) methods have well demonstrated the capability for reproducible, scalable, and layer‐by‐layer fabrication of high quality organic/inorganic thin films. Herein, for the first time, the full‐evaporation fabrication of organic–inorganic hybrid ((BA)2Csn−1PbnBr3n+1) Q2D–3D PeLEDs is demonstrated. The morphology and crystal phase of the perovskite are controlled from 3D to 2D by modulating material composition, annealing temperature, and film thicknesses. The confinement of carriers in 3D layers and the energy funnel effect are discovered and discussed. Importantly, a record high external quantum efficiency (EQE) of 5.3% based on evaporation method is achieved. Moreover, a centimeter‐scale PeLED (1.5 cm × 2 cm) is obtained. Furthermore, the T50 lifetime of the device with an initial brightness of 100 cd m−2 is found to be 90 min with a thin layer PMMA passivation, which is among the longest for all PVD processed PeLEDs. Overall, this work casts a solid stepping stone towards the fabrication of high‐performance PeLEDs on a large‐scale. To address the upscalability issue of conventional solution fabrication of perovskite light emitting diodes (PeLEDs), this work demonstrates a full‐evaporation fabrication of PeLEDs. The growth of perovskite from the 3D to 2D crystal phase can be controlled via tuning evaporation and post processing conditions. Devices with respectable performance and operation lifetime are demonstrated, and large size devices are also fabricated.