Magnetic Doping Induced Strong Circularly Polarized Light Emission and Detection in 2D Layered Halide Perovskite

Abstract

The generation, manipulation, and detection of polarized light are the foundations of spin optoelectronics. Polarized light has a wide range of applications in new‐generation information transmission, storage, and quantum communications. Hybrid organic–inorganic halide perovskites have attracted extensive attention recently because of their strong spin–orbit coupling, Rashba splitting, spin‐dependent optical selection, and have been regarded as promising candidates for application in spin optoelectronic devices. Herein, the authors report the successful synthesis of 2D layered lead halide perovskites (PEA)2PbI4 (PEI) doped with magnetic metal Co2+ and the observation of strong circularly polarized photoluminescence and photoresponse. The introduction of magnetic metals in perovskites can induce an analogous Zeeman effect in the system, which can increase its energy degeneracy, giving rise to an imbalanced population of electronic spin states, thereby enhancing the spin polarization in doped samples. Thus, a maximum circularly polarized PL of 35% is observed at room temperature. Moreover, the achieved Co2+‐doped (PEA)2PbI4 also exhibits a selective photoresponse with circularly polarized light (CPL) emission, and an outstanding anisotropy factor of 0.41 for photocurrent is achieved. The experimental results lay the foundation for the controlled synthesis of magnetically doped perovskites as well as applications for direct CPL detection in spin optoelectronics.

Symmetry-Broken 2D Lead–Tin Mixed Chiral Perovskite for High Asymmetry Factor Circularly Polarized Light Detection

“…In recent years, hybrid perovskite materials consisting of organic chiral molecules and an inorganic framework provide new freedom for circularly polarized light detection. − In combination with symmetry restriction endowed by organic chiral molecules and excellent semiconductor properties from the inorganic framework, chiral hybrid perovskite provides an ideal material for the construction of a direct circularly polarized light detector. − A photodetector based on chiral perovskite shows an unprecedented high asymmetrical factor . To enhance device performance, significant efforts are made to improve circularly polarized absorption such as molecular engineering, , dimensionality manipulation, − and nanostructure engineering.…”

Composition and structure regulation of Ruddlesden–Popper perovskite for light-emitting diodes applications

“…Another additive is a metal ion, forming mixed perovskites with multiple types of ''A'' ions to improve the poor electrical properties. [45][46][47][48][49][50][51][52] Ag + ions were added to form the PEA 2 (Ag x Cs 1Àx ) nÀ1 Pb n Br 3n+1 perovskite, achieving defect passivation, carrier balance, and morphology improvement. 45 The crystal formation process was attributed to the strong affinity between Ag + and Br À , which optimized the ion balance and the disorderly crystal orientation.…”

“…Liu et al synthesized Co 2+ doped (PEA) 2 PbI 4 perovskites that exhibited circularly polarized photoluminescence. 51…”

Exciton splitting in 2D layered metal-halide perovskites

“…[1][2][3][4] Bidimensional con nement of optical excitations induces a blueshift of the bandgap with respect to 3D parent compounds, enhances the exciton binding energy 2,[5][6][7][8] and favors symmetry breaking, Rashba spin-dependent energy splitting and ferroelectricity. [9][10][11][12][13] The optical absorption spectrum of layered perovskites is dominated by an intense exciton peak below the band edge, with estimated binding energies of hundreds of meV, leading to the assumption that light absorption creates bound excitons as excited states. Layered perovskites have found ample use in photovoltaics, notwithstanding the fact that bound excitons should be detrimental to e cient separation of opposite charge carriers in solar cells.…”