Photon and Phonon Coherence to Enhance Photoluminescence by Magnetic Polarons in Mn-Doped Rb₃Cd₂Cl₇ Perovskites

Abstract

All-inorganic metal halide perovskite semiconductors have great potentials in lighting applications, but the effect of excitonic magnetic polarons (EMPs) in the transition metal (TM) ion-doped halide perovskites on their luminescence processes has not been extensively understood. Here, we have synthesized Mn 2+doped Rb 3 Cd 2 Cl 7 perovskite powders with different doping amounts by a hydrothermal method. After Mn(II) is doped, Rb 3 Cd 2 Cl 7 gives strong emission, though the Rb 3 Cd 2 Cl 7 powder itself does not emit light. This emission originates from the intrinsic self-trapped exciton (STE) formation enhanced by the ferromagnetic Mn−Mn pair with spin−spin coupling, that is, the magnetic polaron whose astonishing luminescence at 587 nm has a quantum yield up to 147%. Some shallow trapped centers below the conduction band out of high d levels by localized EMPs after photoexcitation are proven to add to this luminescence process. The thermoluminescence phenomenon with rising temperature proves that these shallow trapped carriers are present with phonon and multiphonon notation, and their efficient transfer to the conduction band and the STE state occurs via the electron−phonon coupling during photoexcitation. This compound provides a new way for TM-doped perovskite material design and applications for magneto-optical and display technology.

Passivation of Organic–Inorganic Hybrid Perovskite with Poly(lactic Acid) to Achieve Stable Red-Light Flexible Films

“…However, the excitons will be captured by nearby traps and returned to VB in a nonradiative manner. When Mn 2+ is doped into PC, the discrete energy levels generated by Mn 2+ can serve as a bridge that facilitates ET from the organic T 1 to the 3 E g of Cd 2+ . , Moreover, the introduction of Mn 2+ can effectively passivate the defect trap and reduce the nonradiative decay, thereby resulting in a significant increase in the red emission efficiency. Owing to the excellent passivation effect in m PC-M, it displays the highest quantum yield among these doped perovskites.…”

Multiexciton Generation from a 2D Organic–Inorganic Hybrid Perovskite with Nearly 200% Quantum Yield of Red Phosphorescence

“…Due to the large energy level difference between organic triplet state (2.65 eV) and inorganic Cd triplet state (2.0 eV), the efficiency of Dexter energy transfer between them is very low, which can only produce weak red phosphorescence. Due to the existence of Mn 2+ in PACC‐M, some excitons in the organic triplet state can reach the 3 E g of [CdCl 6 ] 4− through the STE state of [MnCl 6 ] 4− (2.11 eV), [ 22 ] which improves the Dexter energy transfer efficiency and makes the red phosphorescent emission dominate. Under the excitation of higher energy (>269 nm, Figure a), although the organic and inorganic components of PACC are excited at the same time, due to the existence of deep traps (Figure 3e), the red phosphorescence efficiency is not high, and the double emission composed of blue and red RTP is obtained.…”