One-Dimensional Highly-Confined CsPbBr₃ Nanorods with Enhanced Stability: Synthesis and Spectroscopy

Abstract

One-dimensional (1D) colloidal lead halide perovskites (LHPs) have potential as quantum emitters. Their study, however, has been hampered by their previous instability, leaving a gap in our understanding of structure–property relationships in colloidal LHPs with anisotropic shapes. Here, we synthesize stable, highly-confined 1D CsPbBr3 nanorods (NRs) and demonstrate their structural details and photoluminescence (PL) properties at both the ensemble and single particle levels. Using amino-terminated copolymers, we are able to stabilize and characterize 1D CsPbBr3 NRs utilizing transmission electron microscopy (TEM) and small angle scattering (SAS). Scanning transmission electron microscopy reveals that these NRs possess structural defects, including twists and inhomogeneity. Solution-phase photon correlation spectroscopy shows low biexciton-to-exciton quantum yield ratios (QYBX/QYX) and broad spectral line widths dominated by homogeneous broadening.

Shape-controlled synthesis of one-dimensional cesium lead halide perovskite nanocrystals: methods and advances

“…As aforementioned, the methods successfully applied in 1D CsPbBr 3 NC synthesis can be divided into six categories based on the common features of the method. 34–54 These methods are also categorized into two: direct synthesis methods and post-synthetic methods (Scheme 1). HIM, RTRM, and US are direct synthesis methods, while ICT, CC, and SA are post-synthetic methods.…”

“…In addition to the mostly used OA/OAm ligand pair in HIM, some CsPbX 3 NWs or NRs were successfully synthesized using new ligand pairs. 35,54 Manna et al found that the width of the CsPbBr 3 NWs can be tuned using a mixture of alkyl amines and a short alkyl carboxylic acid. 35 Using a ternary ligand system of oleylamine/octylamine/hexanoic acid (Scheme 4), they synthesized CsPbBr 3 NWs and were able to tune the width of the NWs from 10 AE 1 (beyond the quantum confinement regime) to 3.4 AE 0.5 nm (within quantum confinement regime) by increasing the concentration of the short chain acid (Fig.…”

“…6). 54 To improve the stability of the 1D NRs, a polymer ligand, amino-terminated poly(styrene)-block-poly(1,4-isoprene) (Scheme 4), was added to bind the formed 1D NRs at the end of the synthesis stage. By adjusting the volume ratios of the anti-solvent mixture of acetonitrile/ethyl acetate in purification, two length samples of 14.5 AE 0.4 and 78.8 AE 26.4 nm can be separated.…”

“…However, some examples have shown successful width control in the synthesis of the 1D CsPbBr 3 NCs, and the quantum confinement PL can be achieved. 34,35,[37][38][39]48,53,54 For example, Yang prepared ultrathin CsPbBr 3 NWs with a diameter of 2.2 AE 0.2 nm. 53 The maximum PL wavelength (l max ) of this NW is 442 nm; it emits bright blue emission with a PLQY of 30%.…”

“…34,46 Another way is post-synthetic halide ion exchange. 39,42,45,50,[52][53][54] This is a mature method to obtain PL multicolor CsPbX 3 (X = Cl, I) NCs using CsPbBr 3 as a template (Fig. 16).…”