Control of Emission Color of High Quantum Yield CH₃NH₃PbBr₃ Perovskite Quantum Dots by Precipitation Temperature

Abstract

Emission color controlled, high quantum yield CH3NH3PbBr3 perovskite quantum dots are obtained by changing the temperature of a bad solvent during synthesis. The products for temperatures between 0 and 60 °C have good spectral purity with narrow emission line widths of 28–36 nm, high absolute emission quantum yields of 74% to 93%, and short radiative lifetimes of 13–27 ns.

A stable lead halide perovskite nanocrystals protected by PMMA

“…S8). The average anchoring point number of polymer chain on the MAPbBr 3 NCs can be quantitatively determined by the FTIR spectra of pure PMMA, SNBP films and PLAR films [26,29,30,34]. The anchor point number of each chain in PLAR films is about twice as much as that of SNBP films (Supplementary Text S1 and Fig.…”

“…Here a coating of perovskite nanocrystals (NCs) was anchored via the ligand-assisted reprecipitation (LAR) which usually offers good surface coating on NCs [29,30]. To bond the Pb cations of perovskite NCs, polymethyl methacrylate (PMMA) was introduced on HOIP NCs by LAR method.…”

Strong Quantum Confinement and Fast Photoemission Activation in CH3NH3PbI3 Perovskite Nanocrystals Grown within Periodically Mesostructured Films

“…A single peak at a wavelength of λ 0 = 775 nm (E g = 1.60 eV) was detected in the PL spectrum of the scaffold-free MAPbI 3 film used for comparison, which corresponds to the photoemission peak already reported for the bulk MAPbI 3 perovskite. [5] Crystallites synthesized within periodically porous films displayed PL peaks at λ 0 = 692 nm (E 0 = 1.79 eV), λ 0 = 686 nm (E 0 = 1.81 eV), λ 0 = 677 nm (E 0 = 1.83 eV), λ 0 = 660 nm (E 0 = 1.88 eV), and λ 0 = 638 nm (E 0 = 1.94 eV), where the surfactant employed to achieve each one of the mesostructures is indicated. This implies a maximum blueshift of Δλ 0 = 137 nm (ΔE 0 = 0.34 eV), one of the largest so far reported for MAPbI 3 crystallites.…”

“…[13] Evidence of precise control of the optical properties of MAPbI 3 over a wide spectral range has been reported from colloidal suspensions attained using a two-step process involving the In order to create a stable solid dispersion of MAPbI 3 quantum dots, we follow a standard one-step procedure that starts by dissolving precursors in N,N-dimethylformamide. [5] The solution is then spin coated onto periodically mesostructured metal oxide, namely, TiO 2 or SiO 2 , films of controlled thickness and open porosity, which have been previously deposited on flat glass substrates by a combination of supramolecular templating and dip-coating. [17] Precursor concentration is a critical parameter in order to ensure that the perovskite is grown exclusively within the film pores and to prevent the formation of a bulk perovskite capping layer ( Figure S1, Supporting Information).…”

“…One of the most versatile strategies to tune the optical properties of a semiconductor consists in reducing its size until it becomes of the order of the exciton Bohr radius and quantum confinement effects arise. [1] Different methods have been developed to try to controllably diminish the size of methyl ammonium lead halide (MAPbX 3 , X = Cl, Pb, I) crystals, [2][3][4][5][6][7] motivated by the interest these perovskites generate in the field of optoelectronics. [8][9][10][11][12] Efforts in obtaining dispersions of hybrid organic-inorganic perovskite nanocrystals for optoelectronic applications have mainly focused on MAPbBr 3 and MAPbBr x I 3-x , as this allows achieving visible emission bands.…”