Thermally activated delayed fluorescence materials for organic light-emitting diodes

Abstract

Recently, remarkable advances in thermally activated delayed fluorescence (TADF) materials have attracted dramatic attention due to 100% exciton utilization efficiency in organic light emitting diode (OLED). Although the commercialization of TADF materials is at an early stage, they exhibit enormous potential for next generation OLED for the comparable electroluminescence (EL) performance to metal phosphorescent complexes counterparts but without the presence of precious metal elements. This review summarizes the different types of TADF small molecules with various photophysical properties and the state-of-the-art molecular design strategies. Furthermore, the device engineering and emerging optoelectronic applications, such as organic light-emitting electrochemical cells, organic lasing, and organic scintillators are introduced. It is anticipated that the review can clarify the design of efficient TADF emitters and point out the direction of future development.

Hybridized local and charge transfer dendrimers with near-unity exciton utilization for enabling high-efficiency solution-processed hyperfluorescent OLEDs

“…Unfortunately, traditional fluorophores have a relatively low Z S of only 25% because of the spin statistical limitation. [3][4][5][6] In order to enhance Z S , several strategies have been developed to design highly efficient emitters over the past several decades. 7 For example, noble metal-based phosphorescence provided the most effective approach for high efficiency OLEDs since the first reports from Ma and Forrest groups in 1998.…”

Boosting Organic Light-Emitting Diodes Technology Using Thermally Activated Delayed Fluorescent Emitters: A Review

“…In particular, with the aid of a device-structure-optimizing strategy, the EQEs of monochromic and white TADF diodes are already beyond 30%. In recent years, there has been significant growth in the literature on TADF materials research. − ,− However, the number of comprehensive reviews specifically focusing on TADF materials and their EL color remains relatively limited. Given this gap, a systematic summary is needed to clarify TADF materials based on their EL spectra.…”

“…In the past few years, luminescent material research based on TADF emitters have witnessed significant development. Several pioneering reviews have summarized some important literature in this field. − ,− In this short review, we mainly focus on various types of TADF small molecules exhibiting distinctive luminescent colors, particularly the three primary colors. We aim to elucidate the correlation between the molecular structure and emission wavelength, fluorescence quantum yield, and device performance, offering cutting-edge insights into molecular design strategies.…”

Transforming Thermally Activated Delayed Fluorescence to Room-Temperature Phosphorescence through Modulation of the Donor in Charge-Transfer Cocrystals

“…Organic luminescent materials have shown application prospects of commercialization for organic light-emitting diodes (OLEDs), organic light-emitting transistors (OLETs), bioprobes, sensors, etc., due to their excellent molecular tailoring capability, low cost, large-area fabrication, flexibility, and light weight. When using the organic luminescent materials, improving the exciton-utilizing efficiency is an important scientific issue, especially for the harvest of triplet excitons, which promotes the continuous development and innovation in the organic luminescent materials. − Nevertheless, how to improve the exciton-utilizing efficiency of organic luminescent materials remains challenging. For instance, in an electroluminescence process, the generated singlet and triplet excitons from charge recombination have a ratio of 1:3 according to the spin statistics rule; however, only singlet excitons are spin-allowed and contribute to a maximum exciton-utilizing efficiency of 25% in traditional fluorescence-based devices, which limits the device efficiency .…”