Synthetic Evolution of Colloidal Metal Halide Perovskite Nanocrystals

Abstract

Metal halide perovskite semiconductor nanocrystals have emerged as a lucrative class of materials for many optoelectronic applications. By leveraging the synthetic toolboxes developed from decades of research into more traditional semiconductor nanocrystals, remarkable progress has been made across these materials in terms of their structural, compositional, and optoelectronic control. Here, we review this progress in terms of their underlying formation stages, synthetic approaches, and postsynthetic treatment steps. This assessment highlights the rapidly maturing nature of the perovskite nanocrystal field, particularly with regard to their lead-based derivatives. It further demonstrates that significant challenges remain around precisely controlling their nucleation and growth processes. In going forward, a deeper understanding of the role of precursors and ligands will significantly bolster the versatility in the size, shape, composition, and functional properties of these exciting materials.

Advances in the Stability of Halide Perovskite Nanocrystals

“…Besides the above-discussed colloidal injection synthetic routes, non-injection methods such as convection, solvothermal, microwave, and ultrasonication methods, have also been developed for the preparation of stable metal halide PNCs. In this review, we will not discuss those non-injection methods further, but an interest reader can refer to [14,40] for a deep overview.…”

“…Additional applied strategies on cation exchange had negative effects on stabilizing the original PNCs, as in the case of the decomposition of native CsPbX 3 PNCs upon the substitutions of Cs + cations by Rb + , Ag + or Cu + at A-site, and of Pb 2+ cations by Ge 2+ or Bi 3+ at B-site [40,55]. Several possible factors can affect the decomposition, including incompatible ion sizes, oxidation induced instability, or thermodynamics dependent phase competition [10].…”

“…To solve this problem, by mixing A-site cations, the tolerance factor of as-synthesized Rb 1− x Cs x PbX 3 PNCs can be effectively enhanced. However, these PNCs still exhibited comparable PLQYs to that of CsPbX 3 NCs [40]. In addition, tuning the A-site with larger cations reduces the morphological dimensionality of PNCs to 2D sheets or platelets, 1D rods or wires, or 0D dots or clusters [81].…”

“…Various chemical approaches have so far been reported to synthesize PNCs with sizes in the range from tens of micrometers to several nanometers and with variable morphologies, such as nanocubes (3D), nanoplatelets (2D), nanorods and nanowires (1D) and spherical quantum dots (0D) [6,40,128]. Using the hot-injection method, Deng’s group synthesized single-crystalline Cs 2 SnI 6 nanocrystals with variable shapes [25].…”

Nanocrystallization of lead‐free Cs3Sb2Br9 perovskites in chalcogenide glass

“…These materials possess the similarity of electronic configuration with that of the lead‐based HPNCs 10 . Lead‐free Cs 3 Sb 2 X 9 HPNCs were mainly fabricated by the solution‐based processes, such as the solvothermal method, colloidal synthesis, hot injection method 11‐13 . Remarkably, solution‐processed Cs 3 Sb 2 Br 9 nanocrystals demonstrated high photoluminescence quantum yield of 46% in the blue spectral region and their emission wavelength is tunable via anion exchange reaction 14 .…”