Zero-dimensional lead-free antimony halide hybrids with efficient dual-band emission and high stability

Commercial down-conversion phosphors rely on rare-earth elements, which can lead to serious resources availability and environmental concerns. Recently, organic-inorganic hybrid lead halides feature broadband emissions and structural tunability are an emerging class of phosphors for solid-state lighting (SSL). However, low photoluminescence quantum efficiency (PLQE) and heavy metal lead atoms hinder hybrid lead halides application. In this work, we reported highly efficient zero-dimensional (0D) eco-friendly antimony chloride, (TPA)₂SbCl₅ (TPA = tetrapropylammonium), in which the pyramid-shaped [SbCl₅] ²⁻ species are periodically mosaic in the matrix of organic molecules TPA+ to form a hostguest structure. Under 400 nm excitation, the yellow-emitting (TPA)2SbCl5 shows a PLQE of 86.7% at room temperature. Interestingly, a small high-energy spectrum will appear upon 300 nm excitation. According to the photoluminescence (PL), PL excitation (PLE) spectra, and PL decay dynamics, the high-energy emission spectrum is originated from the singlet, the low-energy broadband emission is derived from triplet self-trapped excitons (STEs). The eco-friendly (TPA)₂SbCl₅ with high stability can be a potential candidate as lighting phosphors.