Weak magnetic field-dependent photoluminescence properties of lead bromide perovskites

Abstract

The strong spin–orbit coupling (SOC) in lead halide perovskites, when inversion symmetry is lifted, has provided opportunities for investigating the Rashba effect in these systems. Moreover, the strong orbital moment, which, in turn, impacts the spin-pair in singlet and triplet electronic states, plays a significant role in enhancing the optoelectronic properties in the presence of external magnetic fields in lead halide perovskites. Here, we investigate the effect of weak magnetic fields (<1 T) on the photoluminescence (PL) properties of [Formula: see text] nanocrystals with and without Ruddlesden–Popper (RP) faults and single crystals of [Formula: see text]. Along with an enhancement in the PL intensity as a function of an external magnetic field, which is observed in both lead bromide perovskites, the PL emission red-shifts in [Formula: see text] nanocrystals. Density-functional theory calculations of the electronic band-edge in [Formula: see text] show almost no change in the energy gap as a function of the external magnetic field. The experimental results, thus, suggest the role of mixing of the triplet and singlet excitonic states under weak magnetic fields. This is further deduced from an enhancement in PL lifetimes as a function of the field in [Formula: see text]. In [Formula: see text], an increase in PL intensity is observed under weak magnetic fields; however, no changes in the peak energy or PL lifetimes are observed. The internal magnetic fields due to SOC are characterized for all three samples and found to be the highest for [Formula: see text] nanocrystals with RP faults.

Dielectric effects, crystal field, and shape anisotropy tuning of the exciton fine structure of halide perovskite nanocrystals

“…This study can serve as a basis for advanced investigations such as those using a magnetic field to explore or control the photoluminescence properties and the EFS by taking into account polaronic effects and varying the dimensionality (0D nanocrystals, nanoplatelets) as in Refs. [39,98,99].…”

A hot phonon bottleneck observed upon incorporation of SnF2 to MASnI3 films and its possible role in increasing photocarrier diffusion length

“…Indicated by the solid red line, we fit the PL temporal decay curves with a single exponential function, I = I 0 + A 1 e −t/τ . 34,35 The 15% doped sample has the longest lifetime (2.16 ns), and all these doped films have a longer photocarrier lifetime, which indicates that SnF 2 doping reduces the nonradiative recombination and improves the possible photocarrier extraction in solar cells.…”

Engineering and Controlling Perovskite Emissions via Optical Quasi‐Bound‐States‐in‐the‐Continuum

“…[ 27 ] However, it is typically accompanied by significant broadening of full‐width‐at‐half‐maximum (FWHM), intensity quenching and requires a sophisticated setup which is impractical for many applications. Alternatively, leveraging the Rashba, [ 29,30 ] Zeeman, [ 31 ] or Stark effects [ 32 ] under DC magnetic field or circularly polarized pumping enables the breaking and detection of the triplet state to manipulate their radiative channels, where a PL shift of ≈6.6 nm (≈30 meV) [ 33 ] can manifest. Nevertheless, these approaches often yield multiple emission with bands, rendering them unsuitable for devices that require a single emission peak.…”