Temperature-responsive emission and elastic properties of a new 2D lead halide perovskite

Two-dimensional (2D) organometallic halide perovskites (OHPs) are promising optoelectronic materials because of their excellent stability and tunable band gaps. Herein, we report the optical and elastic properties of a newly synthesized 2D lead halide perovskite, (C9H14ON)2PbI4 (C9H14ON+ = 4-methoxyphenethylammonium), by a combined experimental and theoretical approach. Our experiments demonstrate that (C9H14ON)2PbI4 shows a strong green emission under ambient conditions which is ascribed to its band gap of 2.4 eV. Moreover, our temperature-dependent photoluminescence (PL) experiments in the temperature range of 143-283 K reveal that the green emission red-shifts with increasing temperature, which is primarily attributed to the synergistic effect of thermal expansion and electron-phonon interactions. The elastic properties, obtained from density functional theory calculations, reveal that (C9H14ON)2PbI4 has relatively low modulus and anisotropy compared with other 2D materials.