Mn(II)-doped 2D perovskite for light emitting devices

TL;DR

This paper demonstrates that Mn(II) doping in 2D perovskites enhances photoluminescence and enables electroluminescence in light-emitting devices by controlling defect states and energy transfer processes.

Contribution

It introduces a defect engineering strategy using Mn(II) doping to improve luminescence and achieve electroluminescence in 2D perovskite-based devices.

Findings

Quantum yield surpassing 20% in doped films

Efficient energy transfer to Mn²⁺ centers demonstrated

First electroluminescence from Mn²⁺ transition in 2D perovskite devices

Abstract

Low dimensional perovskites are considered good candidates for light emitting applications given the high exciton binding energy which should in principle improve the radiative recombination efficiency. Yet, single-layered two-dimensional (2D) perovskite films are strongly limited by trap-assisted recombination and suffer from low luminescence yields, hampering their application in electroluminescence devices. Here, we use ad hoc synthetic and defect engineering strategies to overcome such issue. We employ metallic doping to controllably introduce luminescent impurities in a matrix made of 2D perovskite $NMA_{2}PbX_{4}$ based on the cation NMA = 1-naphtylmethylammonium. By means of temperature-dependent and time-resolved spectroscopy we demonstrate efficient energy transfer to $Mn^{2+}$ centres. Such process avoids the funnelling of the photo-excited species in inefficient recombination channels represented by intra-gap trap states and enhances photoluminescence, with quantum yield surpassing 20% in doped films. Eventually, we embody Mn-doped $NMA_{2}PbBr_{4}$ in a light emitting diode architecture and show, for the first time, electroluminescence from the $Mn^{2+}:^{4}T_{1}-^{6}A_{1}$ transition. This proof-of-concept demonstration shows the potential of doping in layered perovskites and prompt for the study of a wider range of host/guest structures.