Research progress in high colour purity organic light emitting devices

In order to enable organic light emitting display technology to meet the colour gamut standard set by the International Telecommunication Union for Ultra HD TV (BT 2020), the research and development of high colour purity organic light -emitting device (OLED) is important. In this review, we present the latest developments and important research on high colour purity OLEDs in terms of both narrow -band light -emitting materials and microcavity OLEDs, respectively. This paper analyses the effect of vibrational coupling of molecules on the colour purity of organic light -emitting materials, and discusses current methods to improve the colour purity for fluorescent, phosphorescent and thermally -activated delayed fluorescence materials, respectively, and summarizes the latest material design strategies and research results. The principles of the microcavity effect is introduced and its modifying and narrowing effects on the spectra of organic light -emitting devices is analyzed, and then the design of device structures to achieve high colour purity light -emitting using the microcavity effect is presented. Finally, we discuss the future prospects and challenges of high colour purity OLED devices in the display field.