Ten‐Gram‐Scale Synthesis of FAPbX₃ Perovskite Nanocrystals by a High‐Power Room‐Temperature Ultrasonic‐Assisted Strategy and Their Electroluminescence

Abstract

FA + = NH 2 CH = NH 2 + , X = Cl, Br, and I or their mixture) have been grown into the candidate materials for optoelectronic devices, such as light-emitting diodes (LEDs), liquid crystal display (LCD) backlight, solar cells, lasers, and photodetectors thanks to the excellent optical capabilities and low-cost solution processability. [1][2][3][4][5][6][7][8][9][10][11][12] Among the above-mentioned perovskites, FAPbBr 3 shows unique advantages: first, comparing to MAPbBr 3 , FAPbBr 3 performs better stability, which is crucial for the practical application. [13] The origin is that the ion diameter Metal halide perovskite nanocrystals (NCs) have shown significant potential in light-emitting applications due to the unique luminous properties, such as high color purity, tunability, and solution processability. However, the large-scale production of perovskite NCs with high-quality for meeting the commercial applications is still a challenge. Herein, a facile room-temperature synthesis of ten-gram-scale FAPbX 3 (FA + = HC(NH 2 ) 2 + , X = Br, or mixed halide system Cl/Br and Br/I) NCs by a high-power ultrasonic-assisted strategy and the electroluminescence for light-emitting diodes (LEDs) is reported. The uniform high-power radiation avoids the adverse effects caused by heating and stirring unevenness, and no inert gas is needed in the reaction process. Meanwhile, the room temperature reaction reduces the crystallization rate of the NCs, leading to the successful synthesis of ten-gram-scale high-quality FAPbX 3 perovskite NCs. The resulting NCs show size-focus distribution and high photoluminescence quantum yields of 93%, and the adjustable photoluminescence spectra from 453 to 695 nm by manipulating halide compositions. Attributed to the acquired FAPbBr 3 NCs, a highefficiency green LED with the maximum current efficiency of 61.3 cd A −1 and external quantum efficiency of 14.1% is also obtained.

High-Brightness Perovskite Light-Emitting Diodes Based on FAPbBr3 Nanocrystals with Rationally Designed Aromatic Ligands

“…We observe negligible improvements in the PLQY for the colloidal solution of the FAPbBr 3 PeNCs purified by ACN consisting of OA ligands with different concentrations (Figure S9). The results are reasonable, considering the slightly higher polarity of the ACN than those of commonly used antisolvents for the purification of PeNCs, e.g., ethyl acetate, in previous work. − Because of the stronger binding affinity of the sulfo terminal group to the perovskite surface, we anticipate several possible functions of the NSA molecules in the NSA-FAPbBr 3 PeNCs: First, the NSA molecules tend to bind with the uncoordinated Pb atoms at the surface of the PeNCs, which are not fully passivated by the OA and OTAm ligands during the materials synthesis. Second, a more efficient ligand compensation than that induced by additional OA is expected when the originally capped OA and OTAm ligands desorb from the surface during the purification using polar ACN solvent.…”

All‐Inorganic Perovskite Nanocrystals with Remarkably Enhanced Optoelectronic Properties Realized by an Alkene‐Free Solvent Strategy and Their Electroluminescence

“…The strong phonon mode at ≈70 cm −1 was assigned to the bending mode of Br-Pb-Br. [22][23][24] Compared to PeNCs-ODE, PeNCs-toluene exhibited a narrower phonon linewidth, illustrating better crystallinity [25] which was beneficial to the PL emission. To evaluate their optical performance, both PeNCs were diluted to an identical optical density (OD) value, meaning that they had the same concentration.…”

Formamidinium Lead Halide Perovskite Nanocomposite Scintillators

“…Figure 1A shows dispersions of these nanocrystals in toluene, illuminated by a UV torch, demonstrating their luminescence in a range of colours, from purple to green. If necessary, emission wavelengths in red could also be produced, with iodine as the X cation (see, e.g., [39]). Figure 1B shows emission wavelengths for the FAPbX 3 nanocrystal dispersions, as measured from their room-temperature photoluminescence spectra (shown in the inset).…”