Smoothing Energy Transfer Enabling Efficient Large‐Area Quasi‐2D Perovskite Light‐Emitting Diodes

Abstract

Electroluminescence (EL) efficiency of perovskite light-emitting diodes (PeLEDs) based on a few square millimeters has improved significantly in recent years. Nevertheless, the EL efficiency of PeLEDs would plunge once the active area is enlarged from a millimeter to even a subcentimeter due to the unsmooth energy transfer process among the edge region with numerous nonradiative recombination centers. Herein, an intriguing strategy is developed to realize high-quality quasi-2D perovskite thin film via tuning perovskite precursor rheological properties as well as modulating the substrate surface tension. The perovskite crystallization process is retarded by incorporating a strong chelating ligand into its precursor. Hydroxylamine-O-sulfonic acid, containing a sulfonic acid group and an amino group, acts as a strong chelating agent with lead ions (Pb 2+ ), which exhibit great synergistic potential in defect passivation and crystallization modulation. As a result, a large-area (25 cm 2 ) quasi-2D PeLED achieves an external quantum efficiency of 20.7% with uniform emitting characteristics, a record value among analogous same-size PeLEDs. The work may pave the way to realize high-performance large-area perovskite optoelectronic devices.

Frontiers in Green Perovskite Light‐Emitting Diodes

“…Nowadays, researchers have used octylamine (OTAm), 1-naphthylmethylammonium (NMA), ethoxylated trimethylolpropane triacrylate (ETPTA), etc. as ligands of quasi-2D perovskite to reduce the defect state density of thin films and improve the performance of devices [7,94,130,[154][155][156][157][158][159] .…”

“…Song, Wang and Sun et al. [ 155 ] added hydroxylamine‐O‐sulfonic acid (ASC) to the precursor solution and found that sulfonic acid groups were good candidates for chelating Pb 2+ . By recording the variation of PL with rotating coating time, it can be seen that ASC can inhibit the rapid crystallization process of quasi‐2D perovskite.…”