Energy Transfer and Self-Trapping Exciton Luminescence in Sb³⁺-Doped Two-Dimensional Layered Dion–Jacobson Phase Cadmium-Based Perovskites

Abstract

Two-dimensional (2D) Dion−Jacobson (D−J) phase metal halides have been extensively studied for their excellent optical properties. However, the charge/energy transfer between the host and dopant of Sb 3+ -doped 2D structures has rarely been reported. Here, Sb 3+ -doped (PPDA)CdCl 4 (PPDA = p-phenylenediamine) 2D layered D−J phase perovskites with strong electron−phonon coupling and fast energy transfer (E-T) from the host to the dopant lead to strong yellow emission with a photoluminescence quantum yield of 75.4%. Femtosecond-transient absorption (fs-TA) spectra reveal that Sb 3+ -doped 2D layered perovskites exhibit positive phonon-coupled electronic states with a biexcitonic nature, as well as the E-T mechanism from the bound excitons of the host material to the Sb 3+ dopant for the CB and VB state mixing between Sb and Cd. Further, we exhibited Sb 3+ -doped (PPDA)CdCl 4 in the application of solid-state lighting due to its superb optical properties and impressive stability. This work provides new insights for investigating the optical properties of 2D luminescent materials, especially the exciton−dopant exchange interactions in Sb 3+ -doped 2D D−J phase perovskites and also promotes the widespread use of this material in solid-state lighting.