Dimensionality Control of Inorganic and Hybrid Perovskite Nanocrystals by Reaction Temperature: From No‐Confinement to 3D and 1D Quantum Confinement

Abstract

This work focuses on the systematic investigation of the shape,s ize, and composition-controlled synthesis of perovskite nanocrystals (NCs) under inert gas-free conditions and using pre-synthesized precursor stocksolutions.Inthe case of CsPbBr 3 NCs,w ef ind that the lowering of reaction temperature from ~175 to 100 8 8Ci nitially leads to ac hange of morphology from bulk-like 3D nanocubes to 0D nanocubes with 3D-quantum confinement, while at temperatures below 100 8 8Ct he reaction yields 2D nanoplatelets (NPls) with 1Dquantum confinement. However,t oo ur surprise,a th igher temperatures (~215 8 8C), the reaction yields CsPbBr 3 hexapod NCs,w hich have been rarely reported. The synthesis is scalable,a nd their halide composition is tunable by simply using different combinations of precursor solutions.T he versatility of the synthesis is demonstrated by applying it to relatively less explored shape-controlled synthesis of FAPbBr 3 NCs.D espite the synthesis carried out in the air,b oth the inorganic and hybrid perovskite NCs exhibit nearly-narrow emission without applying any size-selective separation, and it is precisely tunable by controlling the reaction temperature.

Deciphering the Relevance of Quantum Confinement in the Optoelectronics of CsPbBr3 Perovskite Nanostructures

“…Metal halide perovskites (PVKs) have spurred enormous curiosity among researchers with their impressive tunable properties like carrier mobility, long carrier lifetimes, bandgaps, near unity photoluminescence (PL) quantum yields, etc . Downstreaming from bulk to two-dimensional (2D), one-dimensional (1D), and zero-dimensional (0D) PVKs, the nanoconfined structures exhibit distinct alterations in charge carrier recombination dynamics, exciton binding energies, optical and electronic bandgaps, etc. − The versatile chemical routes and synthetic conditions like reaction temperature, time, and varied capping ligands prompt the growth dynamics of nanostructures such as the PVK quantum dot (PQD), PVK nanoplatelet (PNPL), PVK nanorod (PNR), PVK nanowire (PNW), etc. ,− Such diversity in tweaking their size, shape, optical features, etc., makes them superior in potential applications in many optoelectronics and photovoltaic devices . The charge extraction of these devices is governed by several fascinating phenomena like charge transfer (CT) and diffusion across the interfaces and interlayer energy transfer, charge transport, etc. − Efficient interfacial CT prior to their carrier recombination ultimately improves the device performance anomalously.…”

Stable and Bright CsPbX3 Nanocrystals in Metal–Organic Frameworks for White Light-Emitting Diodes

“…37,38 This is ascribed to the fact that the size of CsPbBr 3 NCs was small compared with the exciton Bohr radius (3.5−7 nm). 5,39 Therefore, this further proved that the quantum confinement effect existed in perovskite NCs. 40 To understand the exciton and carrier dynamics of luminescent samples, the fluorescence lifetime decay curves of CsPbBr 3 NCs and CsPbBr 3 @Pb-MOF composites tested are shown in Figure 2c.…”

“…In contrast, the narrow emission peak of the pure CsPbBr 3 NC sample was located at 516 nm, and the FWHM of the PL spectrum was 21 nm, as clearly exhibited in Figure S7 (see Supporting Information). It is obvious that the absorption band edges and emission wavelength of CsPbBr 3 @Pb-MOF composites were greater than those of pure CsPbBr 3 NCs. , This is ascribed to the fact that the size of CsPbBr 3 NCs was small compared with the exciton Bohr radius (3.5–7 nm). , Therefore, this further proved that the quantum confinement effect existed in perovskite NCs …”

Colloidal Metal‐Halide Perovskite Nanoplatelets: Thickness‐Controlled Synthesis, Properties, and Application in Light‐Emitting Diodes

“…The key parameters to control for NC synthesis include the reaction temperature, precursor ratio, ligand concentration, acid‐base equilibrium of ligands, and chain‐length of alkylamine ligands. [ 9,14,18,72,73 ] The synthesis methods for perovskite NPls can be broadly classified into three main categories, as illustrated in Figure . Among these, hot injection has been extensively explored for the shape‐controlled synthesis of inorganic perovskite NCs.…”