Recent advances and prospects for high‐efficiency blue hot exciton organic light‐emitting diodes

Abstract Organic light‐emitting diodes (OLEDs) have made great progress and occupy an important position in flat‐panel display market in the past years. Organic emitters have been developed from the first generation of fluorescent materials to the second generation of phosphorescent materials, and to the new generation of luminogens with the ability to harvest non‐emissive triplets, including triplet–triplet annihilation (TTA) materials, thermally activated delayed fluorescence materials, hot exciton materials, and doublet radical materials. The development of fluorescent materials that emit shortwavelength blue light is especially essential for the future use of OLED displays. Hot exciton material mainly harvests the triplet excitation through high‐lying reverse intersystem crossing (hRISC) process from T n ( n ≥ 2) to S m ( m ≥ 1). The fast hRISC process has proved to result in the shortened lifetime of triplet exciton at nanoseconds level and greatly avoid the gathering of triplet excitons. In this respect, hot exciton materials show high potential in solving the equilibrium problem of blue emission, efficient excitation utilization, and low efficiency roll‐off at high brightness. This review systematically summarizes recent advances in hot exciton OLEDs. The fundamental principles regarding molecular design are discussed, and representative reported hot exciton luminogens are summarized and analyzed, along with their structure–property relationships and OLED applications. The review aims to provide valuable insights for the future development of high‐performance and stable blue OLEDs based on this innovative mechanism.