In-depth study on the structures and properties of rare-earth-containing perovskite materials

Synthesis, structure and red-light emission of a manganese halide directed by a methyldiphenylphosphine oxide complex

Controlling the optical activity of halide perovskite materials through modulation of the coordination configurations of the metal ions is important. Herein, a novel manganese-based halide, specifically diaquatetrakis(methyldiphenylphosphine oxide)manganese(II) tetrachloridomanganate(II), [Mn(C13H13OP)4(H2O)2][MnCl4] or [Mn(MDPPO)4(H2O)2][MnCl4] (MDPPO is methyldiphenylphosphine oxide), was synthesized through the solvothermal reaction of MnCl2 with the neutral molecule MDPPO. In this compound, [Mn(MDPPO)4(H2O)2]2+ acts as the cation, while [MnCl4]2- serves as the anion, enabling the co-existence of tetrahedral and octahedral structures within the same system. Remarkably, the compound exhibits efficient red-light emission at 662 nm, distinct from the green-light emission typically observed in MnX4-based halides. Theoretical calculations show that the red emission comes from the charge transfer from the MDPPO to the Mn2+ of [MnCl4]2-. This work provides a new perspective for the design and synthesis of red-light-emitting manganese-based halides with unique structures.

Exciton-phonon coupling in two-dimensional layered (BA)2PbI4 perovskite microplates

Two-dimensional layered (BA)2PbI4 (BA = C4H9NH3) perovskites are emerging as a new class of layered materials and show great potential in optoelectronic applications. Elucidating how exciton-phonon interaction affects the excitonic emission is of great importance for a better knowledge of their optoelectronic properties. In this letter, we synthesized high-quality (BA)2PbI4 microplates via solution methods, and dual-excitonic emission peaks (surface-emission and interior-emission) were detected from the as-grown samples at low temperatures. Furthermore, we determine the energies for the longitudinal optical phonon modes to be ∼27 and ∼18 meV, and the exciton-phonon coupling strengths to be ∼177 and ∼21 meV for the surface-emission and interior-emission bands, respectively. Compared to the interior-emission band, the stronger exciton-phonon interaction results in a considerable degree of spectral broadening and red-shift for the surface-emission with increasing temperature. In contrast, the (OA)2PbI4 (OA = C8H17NH2) microplates with longer alkyl chains between Pb-I layers, exhibit only one excitonic emission peak, as well as a large exciton-phonon coupling strength. Our work clarifies the influence of exciton-phonon coupling on the excitonic emission of (BA)2PbI4 microplates, and also suggests the intrinsic relationship between the exciton-phonon coupling and the length of organic carbon chain ligands.