Synthesis and Photoluminescence Properties of 2D Phenethylammonium Lead Bromide Perovskite Nanocrystals. Issue 10 (13th September 2017) - Guo, Rui
Abstract: Organic–inorganic hybrid perovskites have emerged as promising optoelectronic materials for applications in photovoltaic and optoelectronic devices. Particularly, 2D layer‐structured hybrid perovskites are of great interest due to their remarkable optical and electrical properties, which can be easily tuned by selecting suitable organic and inorganic moieties during the material synthesis. Here, the solution‐phase growth of a large square‐shaped single‐crystalline 2D hybrid perovskite, phenethylammonium lead bromide (C6 H5 C2 H4 NH3 )2 PbBr4 (PEPB), with thickness as few as 3 unit cell layers is demonstrated. Compared to bulk crystals, the 2D PEPB nanocrystals show a major blueshifted photoluminescence (PL) peak at 409 nm indicating an increase in bandgap of 40 meV. Besides the major peak, two new PL peaks located at 480 and 525 nm are observed from the hybrid perovskite nanocrystals. PEPB nanocrystals with different thicknesses show different colors, which can be used to estimate the thickness of the nanocrystals. Time‐resolved reflectance spectroscopy is used to investigate the exciton dynamics, which exhibits a biexponential decay with an amplitude‐weighted lifetime of 16.7 ps. The high‐quality 2D (C6 H5 C2 H4 NH3 )2 PbBr4 nanocrystals are expected to have high PL quantum efficiency and potential applications for light‐emitting devices. Abstract : 2D hybrid perovskites are of great interest due to their remarkable optical and electrical properties. The solution‐phase growth of large square‐shaped 2D nanocrystals of (C6 H5 C2 H4 NH3 )2 PbBr4 is demonstrated. Besides the strong blueshifted photoluminescence (PL) peak at 409 nm, two new PL peaks located at 480 and 525 nm are observed.