Lanthanide-doping enables kinetically controlled growth of deep-blue two-monolayer halide perovskite nanoplatelets

Abstract

Impurity doping has been widely applied in nanomaterial synthesis for modulating the crystallographic phase, morphology, and size of nanocrystalline materials, but mostly by altering thermodynamic equilibriums of final products. Here...

Stable CsPbBr3 Nanoclusters Feature a Disk-like Shape and a Distorted Orthorhombic Structure

“…The PL emission of NCLs was composed of a relatively narrow peak at 410 nm and a broad tail extending up to 600 nm (Figure b), which have been tentatively ascribed to band gap and surface trap emission, respectively. Such optical features indicate that our NCLs are in the strong confinement regime since their absorption peak falls: (i) at higher energies with respect to that of bulk CsPbBr 3 and of 2 monolayer (ML) thick CsPbBr 3 nanoplatelets (∼100 nm diameter); (ii) at lower energies with respect to that of Cs 4 PbBr 6 structures in which all of the PbBr 6 octahedra are disconnected from each other …”

“… (a) HAADF-STEM image and (b) absorption and photoluminescence spectra of purified CsPbBr 3 NCLs. The vertical dashed lines represent the spectral positions of the absorption peaks related to the following species, if they were present in the sample: zero-dimensional (0D) Cs 4 PbBr 6 (●), 53 1 monolayer (oleylammonium) 2 PbBr 4 nanosheets (▲), 50 − 52 CsPbBr 3 nanoplatelets with 2 monolayers thickness (■), 48 and bulk CsPbBr 3 (⧫). (c) DLS analysis of CsPbBr 3 NCLs dispersions in hexane at different concentrations.…”

“…The obtained crude solution was optically transparent and colorless, and the product could be precipitated as a white solid by the addition of ethyl acetate (i.e., antisolvent) followed by centrifugation after 2−3 min. To define the elemental 53 1 monolayer (oleylammonium) 2 PbBr 4 nanosheets (▲), 50−52 CsPbBr 3 nanoplatelets with 2 monolayers thickness ( ■ ), 48 S2, and S3). Both analyses indicated that NCLs have a CsPbBr 2.3 composition with oleylammonium and carboxylate ions (the latter identified via XPS analysis, see Table S3) ensuring charge balance.…”

Oleic acid/oleylamine ligand pair: a versatile combination in the synthesis of colloidal nanoparticles

“…433 In principle, all these synthetic methods using the OAm/OAc ligand pair are also applicable to doped perovskite NPls by adding dopant precursors in the reaction medium. [473][474][475][476] Recently, the ligand pair under discussion was also used in the hot-injection synthesis of lead-free Cs 2 AgBiX 6 (X = Cl, Br, I) double perovskite NPls by Chen and coworkers. 477 In their synthesis, Cs-oleate was injected into an ODE solution containing Ag, Bi and halide precursors together with OAm/OAc.…”

Tunable deep-blue luminescence from ball-milled chlorine-rich Csx(NH4)1−xPbCl2Br nanocrystals by ammonium modulation

“…28,29 When NH 4 + ions were mechanically doped, the PLQYs of Cs 0.7 (NH 4 ) 0.3 PbCl 2 Br, Cs 0.5 (NH 4 ) 0.5 PbCl 2 Br and Cs 0.3 (NH 4 ) 0.7 PbCl 2 Br increased to 28.41%, 35.81% and 39.26%, respectively, comparable to the solution-synthesized PNCs emitting at these wavelengths. 30 The improvements of PLQY are ascribed to filling the surface vacancies with NH 4 + as it enters the CsPbCl 2 Br octahedral framework to substitute Cs + ions, leading to efficient passivation of trapping states and reduction of non radioactive recombination. 20 The PLQY of a non-perovskite NH 4 PbCl 2 Br solution was extremely low that no convincing value could be measured, which was related to the low emission intensity (Fig.…”