Domain Distribution Management of Quasi‐2D Perovskites toward High‐Performance Blue Light‐Emitting Diodes

Abstract

Quasi‐2D perovskites, as one of the promising materials applied in perovskite light‐emitting diodes (PeLEDs), have attracted great attention for their superior semiconductor properties. The inherent multiquantum well structure can induce a strong confinement effect, which is especially suitable for blue emission. However, compared to their green counterparts, blue emitters constructed from quasi‐2D perovskites are more sensitive to n domain distribution (where n represents the number of PbX6 inorganic layers). Suffering from inefficient domain distribution management, blue PeLEDs now face a variety of negative issues, including color instability, multipeak emission, and poor fluorescence yield. In this review, the development of blue PeLEDs and the optical properties of quasi‐2D perovskites are overviewed. Then, a classification and summary of strategies for domain distribution management are proposed. Finally, the challenges and potential directions of domain distribution management in quasi‐2D perovskites are summarized. This review is expected to provide a comprehensive perspective and reference on domain distribution management toward efficient blue quasi‐2D PeLEDs.

Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light‐Emitting Diodes with Chiral Ligands

“…Additionally, the full-width at half-maximum (FWHM) of the PL spectra decreases from 27 to 18 nm with the increasing ratio of L-PMeCl from 0% to 100%. This suggests that the L-PMeCl treatment controls the crystallization process and reduces the coexistence of multiple small-n phase perovskites, [39] which is in accord with the absorption analyses (Figure 1b).…”

“…L-PMeCl-based films may avoid the adverse effects of poor charge transport and non-radiative recombination caused by small-n phases. [38,39] Upon increasing the concentration of PMeCl from 0% to 100%, the PL peaks of perovskite films gradually blueshift from 498 to 484 nm (Figure 1c), while the bandgap changes from 2.42 to 2.49 eV (Figure S2, Supporting Information). These are probably attributed to the incorporation of Cl − from L-PMeCl into the perovskite lattice.…”

Impact of Strontium Doping on Quasi-Two-Dimensional Perovskite Layers for Sky-Blue Light-Emitting Diodes

“…2 It is widely accepted that the inorganic MX 6 4− octahedral cube sheets possess higher dielectric constants, while large organic spacer cations have relatively lower dielectric constants. 3 Since MX 6 4− octahedral cube sheets can be blocked by L large organic cations to form small-n domains with large exciton binding energy (>100 meV), the quasi-2D perovskite layer has more obvious exciton behavior compared with the three-dimensional counterpart. 4,5 Efficient domain distribution control is especially important for a blue quasi-2D perovskite layer.…”

“…In the L 2 A n –1 M n X 3 n +1 molecular formula, L is usually a large organic spacer cation, A is a monovalent cation, M is a divalent metal cation, X is one or a mixed halide anion, and n is the number of MX 6 4– octahedral cube sheets sandwiched between the L large organic spacer cation . It is widely accepted that the inorganic MX 6 4– octahedral cube sheets possess higher dielectric constants, while large organic spacer cations have relatively lower dielectric constants . Since MX 6 4– octahedral cube sheets can be blocked by L large organic cations to form small- n domains with large exciton binding energy (>100 meV), the quasi-2D perovskite layer has more obvious exciton behavior compared with the three-dimensional counterpart. , Efficient domain distribution control is especially important for a blue quasi-2D perovskite layer .…”

High Layer Number (n = 1–6) 2D Ruddlesden–Popper Lead Bromide Perovskites: Nanosheets, Crystal Structure, and Optoelectronic Properties

“…Further comparison of these calculated band positions to those of 3D CsPbBr 3 (Figure c) make it clear that, if the 3D phase exists in a mixed n phase sample, carrier funneling would heavily favor radiative recombination at 525 nm (the PL emission wavelength for 3D CsPbBr 3 ). Indeed, many reports have shown that the suppression of the 3D phase and control of the 2D phase distribution in thin films are critical for LEDs and other optoelectronic devices. ,− Conversely, when making claims about LED or even lasing from related 2D RP perovskites, caution must be taken to rule out light emission from 3D perovskite rigorously.…”