Efficient and High‐Luminance Perovskite Light‐Emitting Diodes Based on CsPbBr₃ Nanocrystals Synthesized from a Dual‐Purpose Organic Lead Source

Abstract

Rational engineering of the surface properties of perovskite nanocrystals (PeNCs) is critical to obtain light emitters with simultaneous high photoluminescence efficiency and excellent charge transport properties for light‐emitting diodes (LEDs). However, the commonly used lead halide sources make it hard to rationally optimize the surface compositions of the PeNCs. In addition, previously developed ligand engineering strategies for conventional inorganic nanocrystals easily deteriorate surface properties of the PeNCs, bringing additional difficulties in optimizing their optoelectronic properties. In this work, a novel strategy of employing a dual‐purpose organic lead source for the synthesis of highly luminescent PeNCs with enhanced charge transport property is developed. Lead naphthenate (Pb(NA)2), of which the metal ions work as lead sources while the naphthenate can function as the surface ligands afterward, is explored and the obtained products under different synthesis conditions are comprehensively investigated. Monodispersed cesium lead bromide (CsPbBr3) with controllable size and excellent optical properties, showing superior photoluminescence quantum yields up to 80%, is obtained. Based on the simultaneously enhanced electrical properties of the Pb(NA)2‐derived PeNCs, the resultant LEDs demonstrate a high peak external quantum efficiency of 8.44% and a superior maximum luminance of 31 759 cd cm−2.

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

“…Metal halide perovskite nanocrystals (PeNCs) have recently emerged as promising candidates for low-cost and high-performance light-emitting diodes (LEDs). − Owing to their unique high defect tolerance property, high-quality PeNCs with near-unity photoluminescence quantum yields (PLQYs) can be obtained under mild synthesis conditions. − Additionally, the light emission of PeNCs exhibits wide tunability and narrow emission line width in the whole visible spectrum, leading to an ultrawide color gamut covering around 100% of the Rec. 2020 color space, − making them superior candidates for applications in high-resolution displays.…”

Lanthanide-doped inorganic halide perovskites (CsPbX3): novel properties and emerging applications

“…The smaller the particle size, the higher the PLQYs, which is beneficial for light-emitting diodes. 65,104 Whereas, for the perovskite QDs with size less than the exciton Bohr diameter (D B ), the PLQYs decrease as observed by Kim et al 105 PLQYs for 5 nm perovskite QDs was about 68%, and 62% for 3 nm. For the small perovskite QDs, the surface-to-volume ratio increased, which promoted the creation of surface traps for the exciton.…”

“…The value of DE accounts for the blue-shift in the emission peak and absorption edge. 104 The bandgap of the CsPbBr 3 as a function of quantum dot size is shown in Fig. 7(h); the square box is the experimental data and the continuous line is the EMA model fitted curve.…”

Insight into Luminescence Enhancement of Alkaline-Earth Metal Ion-Doped CsPbBr3 Perovskite Nanocrystals

“…All-inorganic lead halide perovskites have been widely applied in the fields of optoelectronic devices such as solar cells, , LEDs, − lasers, photodetectors, scintillators, and so on due to their remarkable properties such as ultra-high photoluminescence quantum yield (PLQY), − high color purity, tunable luminescence, , defect tolerance, , simple and low-cost synthesis, and so forth. ,− Compared with the weak optical performance of CsPbCl 3 nanocrystals (NCs) , due to serious defect and poor stability of CsPbI 3 NCs resulting from low phase transition temperature, − CsPbBr 3 NCs have been most widely studied because the most defect states of the CsPbBr 3 NCs are shallow defects, which make the NCs exhibit higher defect tolerance and better photoelectric properties. Nevertheless, the defect state-mediated non-radiative recombination processes in the CsPbBr 3 NCs cannot be negligible; it is still essential to eliminate or reduce non-radiative recombination processes to obtain better photoelectric performance of CsPbBr 3 NCs. ,, …”