Effects of Organic Cation Length on Exciton Recombination in Two-Dimensional Layered Lead Iodide Hybrid Perovskite Crystals

Abstract

In recent years, 2D layered organic-inorganic lead halide perovskites have attracted considerable attention due to the distinctive quantum confinement effects as well as prominent excitonic luminescence. Herein, we show that the recombination dynamics and photoluminescence (PL) of the 2D layered perovskites can be tuned by the organic cation length. 2D lead iodide perovskite crystals with increased length of the organic chains reveal blue-shifted PL as well as enhanced relative internal quantum efficiency. Furthermore, we provide experimental evidence that the formation of face-sharing [PbI] octahedron in perovskites with long alkyls induces additional confinement for the excitons, leading to 1D-like recombination. As a result, the PL spectra show enhanced inhomogeneous broadening at low temperature. Our work provides physical understanding of the role of organic cation in the optical properties of 2D layered perovskites, and would benefit the improvement of luminescence efficiency of such materials.

Room‐Temperature Ion‐Exchange‐Mediated Self‐Assembly toward Formamidinium Perovskite Nanoplates with Finely Tunable, Ultrapure Green Emissions for Achieving Rec. 2020 Displays

“…According to the XRD pattern an interlayer spacing of 3.6 nm can be calculated, the result is in good consistence with the reported relationship d (Å) = 8.06 + 1.59 × n , where n is the number of carbon atoms in the alkylamine (for OA, n = 18) . The strong quantum confinement effect severely blueshifts the PL maxima to 396 nm as shown in Figure S2 (Supporting Information), and a steep excitonic absorption peak can also be observed with a small Stokes shift. Corresponding scanning electron microscope (SEM) image of the as‐prepared OA 2 PbBr 4 NPs is presented in Figure b.…”

Centimeter-scale 2D perovskite (PEA)2PbBr4 single crystal plates grown by a seeded solution method for photodetectors

“…37 was not observed here. Furthermore, the peak intensities increased from 78 to 178 K, reaching a maximum, known as negative thermal quenching behavior, 45 and then decreasing ( Fig. 4(b)), while the band gap peak was slightly red shied as the temperature increased, as observed for most semiconductors ( Fig.…”

Oriented and Uniform Distribution of Dion–Jacobson Phase Perovskites Controlled by Quantum Well Barrier Thickness

“…Optical absorption and photoluminescence (PL) spectra of DJ phase perovskite films are shown in Figure b,c, where PDA‐ and BDA‐based perovskites exhibited similar absorption characteristics to 3D MAPbI 3 counterparts, whereas additional peaks at 610 and 640 nm in PeDA and at 590 nm in HDA were observed. The exciton peaks based on PDA and BDA were not apparent because the short chain spacers reduce the distortion of the DJ phase perovskite compared with the long chain spacers (PeDA and HDA), thereby exhibiting a relatively uniform QW distribution. Moreover, at the same value of n , the number of organic spacers introduced in the DJ phase perovskite was lower compared with the RP phase, so the presence of exciton peaks was not substantially observed in the DJ phase perovskite film when n > 4.…”