Transparent near-infrared perovskite light-emitting diodes

Chenchao Xie,Zhi-Kuang Tan,Xiaofei Zhao,Evon Woan Yuann Ong

doi:10.1038/s41467-020-18110-7

Chenchao Xie, Zhi-Kuang Tan + Show 2 more

Open Access

https://doi.org/10.1038/s41467-020-18110-7

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Journal: Nature Communications	Publication Date: Aug 24, 2020
Citations: 58	License type: open-access

Affiliation: National University of Singapore

Abstract

Mobile and wearable devices are increasingly reliant on near-infrared (NIR) covert illumination for facial recognition, eye-tracking or motion and depth sensing functions. However, these small devices offer limited spatial real estate that is typically already occupied by their full-area electronic color displays. Here, we report a transparent perovskite light-emitting diode (LED) that could be overlaid across a color display to provide an efficient and high-intensity NIR illumination. Our transparent devices are constructed with an ITO/AZO/PEIE/FAPbI3/poly-TPD/MoO3/Al/ITO/Ag/ITO architecture, and offer a high average transmittance of more than 55% across the visible spectral region. In particular, our Al/ITO/Ag/ITO top transparent electrode was designed to offer a combination low sheet resistance and low plasma damage upon electrode deposition. The devices emit at 799 nm with a high total external quantum efficiency of 5.7% at a current density of 5.3 mA cm−2 and a high radiance of 1.5 W sr−1 m−2, and possess a large functional device area of 120 mm2. The efficient performance is ideal for battery-powered wearable devices, and could enable advanced security and sensing features on future smart-watches, phones, gaming consoles and augmented or virtual reality headsets.

Highlights

Mobile and wearable devices are increasingly reliant on near-infrared (NIR) covert illumination for facial recognition, eye-tracking or motion and depth sensing functions
The primary advantage that perovskite LEDs (PeLEDs) offer over other III-V semiconductor chip-based light-emitting diode (LED) lies in their ability to be constructed over large areas on a variety of substrates, allowing them to be suited for electroluminescent display applications such as in televisions, smartphones, and smart-watches
Our transparent PeLEDs are constructed with an indium tin oxide (ITO)/aluminum zinc oxide (AZO)/polyethylenimine ethoxylated (PEIE)/formamidinium lead iodide (FAPbI3)/poly[N,N′-bis(4-butylphenyl)-N,N′-bisphenylbenzidine]/molybdenum trioxide (MoO3)/aluminum (Al)/ ITO/ silver (Ag)/ITO architecture (Fig. 1a), and employ similar active layers as the opaque devices in our previous work[11]

Summary

Introduction

Mobile and wearable devices are increasingly reliant on near-infrared (NIR) covert illumination for facial recognition, eye-tracking or motion and depth sensing functions. NIR perovskite LEDs (PeLEDs) have remained the most successful, demonstrating a combination of high efficiency, good reproducibility, and respectable lifespan.

Results

Conclusion