Yb³⁺‐Doped Phenylethylammonium Lead Bromide 2D Layered Hybrid Perovskite for Near‐Infrared Emission

Abstract

Two-dimensional (2D) layered hybrid perovskites like phenylethylammonium lead bromide [(PEA)₂PbBr₄] show interesting optoelectronic properties and improved moisture stability owing to the repeating quantum-well structure and hydrophobic organic cations, respectively. Doping metal ions in such perovskites leads to exciton-dopant interactions, imparting new optical properties. Here we report synthesis and optical properties of Yb³⁺-doped (PEA)₂PbBr₄. Crystals show plate-like morphology with lateral size of few micrometers. Also, ∼3.5 nm thin nanoplatelets are obtained after sonicating the samples. The host absorbs light via excitonic (and band-band) transition at 407 nm. A part of the generated excitons recombines by emitting light at 414 nm along with host-related non-radiative recombination. Another significant part of the excitons recombines by non-radiatively transferring the energy to the f-electrons of Yb³⁺ dopant ions. The Yb³⁺ ions then de-excite via f-f (²F_5/2→²F_7/2) transition emitting near-infrared (NIR) radiation with a peak at 997 nm. Such NIR-emitting semiconductors with improved performances are desired for NIR light-emitting diode applications.