Bright Free Exciton Electroluminescence from Mn-Doped Two-Dimensional Layered Perovskites

Abstract

perovskites incorporating hydrophobic organic spacer cations show improved film stability and morphology compared to their three-dimensional (3D) counterparts. However, 2D perovskites usually exhibit low photoluminescence quantum efficiency (PLQE) owing to strong exciton-phonon interaction at room temperature, which

Metal Halide Regulated Photophysical Tuning of Zero‐Dimensional Organic Metal Halide Hybrids: From Efficient Phosphorescence to Ultralong Afterglow

“…Multiple π–π stackings could be clearly observed for the TPP + units in TPP 2 ZnCl 4 (Figure 4 b). The much denser packing among TPP + units in TPP 2 ZnCl 4 as compared to that in TPPCl makes the hybrid more rigid, which is attributing to the decreased non‐radiative decay and enhanced PLQE [3f, 11] . This assumption matched well with our analysis of the radiative and nonradiative rates of TPPCl and TPP 2 ZnCl 4 .…”

Momentarily trapped exciton polaron in two-dimensional lead halide perovskites

“…Changing surface ligand to, e.g., BA, PEA or halide to I, Cl will likely affect exciton-phonon coupling strength thus exciton behavior, which will be our following study 66 . In fact, ligand engineering to regulate the crystal rigidity has been shown as an effective way to control exciton-phonon coupling to achieve bright blue Pb-Br perovskite emitters 3 and enhanced yellow electroluminescence from 2D Pb-I perovskites 4 . However, we also note that the origin about low-energy broadband emission in BA-or PEA-PbI 4 2D perovskites is still highly debated 33,48,58,66 .…”

“…This study reveals a complex and dynamic picture of exciton polarons in 2D CsPbBr 3 and have strong implications to their light-emitting applications. Efforts such as ligand engineering 3,4 and cation doping 4 should be made to regulate exciton-phonon coupling strength for high color purity light-emitting devices. After stirring for an additional 1 min, the NPs were precipitated by centrifugation at 3500 r.p.m.…”

“…ecently, two-dimensional (2D) Ruddlesden-Popper (RP) phase lead halide perovskites have emerged as promising light-emitting materials due to their solution processing, tunable bandgap, and high photoluminescence (PL) quantum yield (QY) [1][2][3][4] . With large quantum confinement and reduced dielectric screening, excitons in 2D perovskites are strongly confined with large exciton binding energy 5,6 .…”

Two‐dimensional halide perovskite quantum‐well emitters: A critical review

“…2D perovskite‐based LED was firstly demonstrated in 1994 with (PEA) 2 PbI 4 , which exhibit green emission without EQE and brightness being reported 52 . Since then, different 2D perovskites with different quantum well configurations, such as (PEA) 2 PbBr 4 , (PEA) 2 PbCl 2 Br 2 , (BA) 2 PbBr 4 , have been utilized to fabricate LED devices, which show the EQE as low as 0.31% 53‐57 . At the same time, lead‐free Sn‐based 2D perovskite quantum wells have also captured intense research interests for LEDs, but still suffer from limited EQE (<1%) and poor operational stability 58‐63 …”