All-inorganic perovskite quantum dot light-emitting memories

Meng-Cheng Yen,Junfu Leng,Kang-Hsiang Liu,Chun-Chieh Chang,Yi Peng,Tzu-Hsuan Chang,Kaoru Tamada,Ya-Ju Lee,Chia-Jung Lee

doi:10.1038/s41467-021-24762-w

Abstract

Field-induced ionic motions in all-inorganic CsPbBr3 perovskite quantum dots (QDs) strongly dictate not only their electro-optical characteristics but also the ultimate optoelectronic device performance. Here, we show that the functionality of a single Ag/CsPbBr3/ITO device can be actively switched on a sub-millisecond scale from a resistive random-access memory (RRAM) to a light-emitting electrochemical cell (LEC), or vice versa, by simply modulating its bias polarity. We then realize for the first time a fast, all-perovskite light-emitting memory (LEM) operating at 5 kHz by pairing such two identical devices in series, in which one functions as an RRAM to electrically read the encoded data while the other simultaneously as an LEC for a parallel, non-contact optical reading. We further show that the digital status of the LEM can be perceived in real time from its emission color. Our work opens up a completely new horizon for more advanced all-inorganic perovskite optoelectronic technologies.

Highlights

Field-induced ionic motions in all-inorganic CsPbBr3 perovskite quantum dots (QDs) strongly dictate their electro-optical characteristics and the ultimate optoelectronic device performance
Closepacked CsPbBr3 QDs synthesized by the supersaturated recrystallization (SR) method at room temperature are spun coated on top of the indium tin oxide (ITO) pads at 3000 rpm for 30 s, forming a quasi-continuous film with a thickness of ~800 nm for the light-emitting memory (LEM)
In order to form the latter, either the perovskite precursor solution[26,27,28] or the mixed powers of PbBr2 and CsBr29–31 would need to be subject to a period of high temperature for facilitating the nucleation and crystallization of the bulk perovskites, but the heating process would introduce undesirable thermal stress to the underlying ITO and reduce the electrical conductivity of ITO32,33 and degrade the overall LEM

Summary

Introduction

Field-induced ionic motions in all-inorganic CsPbBr3 perovskite quantum dots (QDs) strongly dictate their electro-optical characteristics and the ultimate optoelectronic device performance. By taking advantage of the fast, electrically switchable ionic motions and the corresponding bifunctionalities (that is, RRAM and LEC) in a single perovskite structure, here we propose and demonstrate a novel all-inorganic perovskite CsPbBr3 LEM by monolithically integrating a perovskite LEC with a perovskite RRAM We show that this all-perovskite LEM could electrically read the encoded data by its RRAM and optically transmit the information through the emission from its LEC at a speed of 5 kHz. We further demonstrate a two-color emitting LEM by employing QDs with two different sizes in the device, enabling the real-time reading of the LEM digital status (either write or erase) by its emission colors. This work could serve as a new paradigm for generating more advanced all-inorganic perovskite optoelectronics and new applications through the synergy of electronics and photonics

Methods

Results

Conclusion