Recently, Academician Prof. Huang Wei and Prof. Jianpu Wang's group from the Key Laboratory of Flexible Electronics and the School of Flexible Electronics (Future Technologies) at Nanjing Tech University proposed a novel strategy to enhance the radiative recombination rate of perovskite phases, achieving record-high efficiency in perovskite light-emitting diodes (LEDs). This work was recently published in Nature entitled "Acceleration of radiative recombination for efficient perovskite LEDs".
The rising demands for more efficient and brighter thin-film LEDs in flat-panel display and solid-state lighting applications have promoted research into three-dimensional (3D) perovskites. These materials exhibit high charge mobilities and low quantum-efficiency-droop, making them promising candidates for achieving efficient LEDs with enhanced brightness. To improve the efficiency of LEDs, it is crucial to minimize nonradiative recombination while promoting radiative recombination. Various passivation strategies have been employed to reduce defect densities in 3D perovskite films, approaching levels close to those of single crystals. However, the slow radiative (bimolecular) recombination has limited the photoluminescence quantum efficiencies (PLQEs) of 3D perovskites to below 80%, resulting in external quantum efficiencies (EQEs) of LED devices below 25%. Huang and Wang's group present a dual-additive crystallization method that enables the formation of highly efficient 3D perovskites, achieving an exceptional PLQE of 96%. This approach promotes the formation of tetragonal FAPbI3 perovskite, known for its high exciton binding energy, which effectively accelerates the radiative recombination. As a result, they achieve perovskite LEDs with a record peak external quantum efficiency of 32.0%, with the efficiency remaining above 30.0% even at a high current density of 100 mA cm-2. These findings provide valuable insights for advancing the development of high-efficiency and high-brightness perovskite LEDs.
https://www.nature.com/articles/s41586-024-07460-7
