Optimizing Broadband Emission in 2D Halide Perovskites

Abstract

Broadband and white-light emitting materials are sought after for applications such as phosphors and LEDs. Some twodimensional (2D) halide perovskites are promising candidates in this realm. Nevertheless, optimizing their photoluminescence quantum efficiency (PLQY) is highly challenging. Herein, we show a new strategy for optimizing the efficiency of the broadband emission of 2D halide perovskites. Specifically, we show that by a combination of halide bonds and halide mixing, the PLQYs of a novel family of materials with the formula (Br-PEA) 2 PbBr x Cl 4−x (Br-PEA = 4-bromo phenethylammonium) can be improved by one order of magnitude, from 3 to 25%; this approach could be useful to many other 2D perovskites.

Broadband yellow and white emission from large octahedral tilting in (110)-oriented layered perovskites: imidazolium-methylhydrazinium lead halides

“…The broadband emissions with large Stoke shifts are usually attributed to self-trapped excitons (STEx). 27,[68][69][70][71][72] Stability of STEx states increases with the enhancement of exciton-phonon coupling, and numerous studies showed that the intensity of STEx PL and Stokes shift increase with increasing distortion of the inorganic layers (decreasing y link ). 27,68,72,73 Since the high level of structural distortions is typical of (110)-oriented perovskites, 36,46,53 these compounds often show STEx related broadband emission, including the white-light one.…”

Two-Dimensional Hybrid Dion–Jacobson Germanium Halide Perovskites

“…So far, there are two main categories of (100)-oriented 2D halide perovskites reported, namely, Ruddlesden–Popper (RP) phases − and Dion–Jacobson (DJ) phases. − The alternating cations in the interlayer space (ACI) types have also been reported, but with fewer examples. , The differences between these types originate from the choice of spacing organic/inorganic cations, with relatively different stacking of the layers. ,, The general formulas for the RP and DJ phases are A′ 2 A n –1 M n X 3 n +1 and A′A n –1 M n X 3 n +1 , respectively, where the larger spacing cation A′ is monovalent (+1) for the RP phases and divalent (+2) for the DJ phases. The RP phases contain monovalent cations interdigitated between the adjacent inorganic layers, and the continuous inorganic layers are shifted with respect to each other by a half-unit cell. , In the case of DJ phases, they consist of short divalent spacer cations between the layers, and the inorganic layers stack exactly on top of each other.…”

Highlighting Recent Research from Latin America in Chemistry of Materials

“…Thus, it is not surprising that other recent manuscripts highlight materials with potential energy and light-emitting/phosphor applications. Organic, hybrid, − and inorganic materials have been the focus of these studies, with a recent review on dual-state emission in organic fluorophores . Studies of 2D halide perovskites were undertaken by a number of different groups, making advances in their design broadly.…”

“…Studies of 2D halide perovskites were undertaken by a number of different groups, making advances in their design broadly. For example, Solis-Ibarra and co-workers showed that the broadband emission of these materials could be enhanced through a combination of halide bonds and halide mixing while the application of pressure can induce phase transitions and, in turn, modulate optical properties as shown by a multicountry collaboration lead by Katrusiak …”

“…14 Studies of 2D halide perovskites were undertaken by a number of different groups, making advances in their design broadly. For example, Solis-Ibarra and coworkers showed that the broadband emission of these materials could be enhanced through a combination of halide bonds and halide mixing 12 while the application of pressure can induce phase transitions and, in turn, modulate optical properties as shown by a multicountry collaboration lead by Katrusiak. 11 Finally, while the manuscripts highlighted thus far emphasize a range of applications, many other papers reflect a deep appreciation for fundamental studies that correlate atomic and nanoscale structure to properties.…”