Development of Blue Light PeLED.. "Move Over OLED TV"

Structure of Developed Blue-Emitting Perovskite Device and Organic (Hole Transport Layer) Material

[Asia Economy Reporter Junho Hwang] A 'perovskite light-emitting device (PeLED)' that solves the challenging issue of blue light implementation in displays has been developed. This device offers higher color purity and better efficiency compared to existing materials. Following OLED, there is growing interest in whether it can be used as a display material for next-generation TVs.

The research team led by Professors Myunghoon Song and Sangkyu Kwak from Ulsan National Institute of Science and Technology, in collaboration with Professor Wanhyung Woo’s team from Korea University’s Department of Chemistry, announced on the 13th that they have developed a PeLED that emits blue light. The research results were published on the 10th in the international journal ACS Nano.

Development of Blue Light PeLED

Comparison of Color Purity (Emission Spectrum Stability) of Light-Emitting Devices

A light-emitting device is a component that produces colors in TVs or mobile phones. PeLED uses perovskite as the color-producing material. Perovskite is a material containing ions, and by changing the types of ions, various colors can be created. Compared to other light-emitting materials, it has a lower production cost and can realize natural colors close to those found in nature, making it highly promising as a next-generation display material.

However, when using this device to produce blue light, power consumption is high. The power efficiency is less than half compared to red or green. The purity of blue light also gradually decreases over time, eventually changing to other colors instead of blue.

The research team solved this problem by developing a method to improve device performance not by complex manipulation of the perovskite material itself but by changing the adjacent material. Instead of using conductive polymers in the 'hole transport layer' adjacent to the perovskite in the light-emitting device, they used conjugated polymer electrolytes as the hole transport layer. As a result, power consumption efficiency was 3 to 4 times higher than with conventional materials, and the electroluminescence spectrum, an indicator of color purity, was significantly stabilized.

Achieving Blue Light by Changing Hole Transport Layer Material

First author researcher Jang Chung-hyun (from the right), Professor Song Myung-hoon, researcher Kim Su-hwan

The research team explained that when the hole transport layer material was changed, the regularity (crystallinity) of the perovskite three-dimensional structure improved, and defects at the interface decreased, greatly enhancing the efficiency of converting electricity into light in the light-emitting device. They also confirmed that the larger the size of the side-chain ions composing the conjugated polymer electrolyte, the clearer the crystallinity of the perovskite material and the fewer defects at the interface.

Jang Choonghyun, the first author of the study, evaluated, "This research is significant in that it solved the fundamental problem of blue PeLEDs not by the perovskite emitting layer itself but by changing the interfacial properties between the perovskite and the hole transport layer (the boundary between different materials)."

Professor Myunghoon Song said, "PeLEDs achieved OLED-level efficiency within a short period of six years, but the blue light efficiency was around 10%. Through this research, both device efficiency and color purity issues have been improved simultaneously, which is expected to accelerate commercialization."

This content was produced with the assistance of AI translation services.