Efficient and Spectrally Stable Blue Perovskite Light‐Emitting Diodes Based on Potassium Passivated Nanocrystals

Yang, Fei; Chen, Hongting; Zhang, Rui; Liu, Xiaoke; Zhang, Weizhuo; Zhang, Jibin; Gao, Feng; Wang, Lei

doi:10.1002/adfm.201908760

Cited by 154 publications

(167 citation statements)

References 50 publications

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“…Substantial efforts have been made in the past several years to obtain blue perovskite emitters, such as perovskite nanocrystals (NCs), [ 19–25 ] 2D perovskite nanoplatelets, [ 26–32 ] and quasi‐2D perovskites. [ 33–39 ] In particular, the quasi‐2D perovskites are rising as efficient luminescent materials for highly performed blue PeLEDs due to the cascade energy landscape for efficient exciton transfer and the subsequent radiative recombination.…”

Section: Figurementioning

confidence: 99%

High‐Performance Blue Perovskite Light‐Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi‐2D Perovskite Layers

et al. 2020

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Recently, impressive external quantum efficiencies (EQEs) exceeding 20% are obtained for green, red, and near-infrared perovskitebased LEDs (PeLEDs) through the efforts of perovskite material optimization and device architecture design. [8-10] These achievements firmly prompt the potential applications of PeLEDs in display and illumination fields. However, compared with the efficient PeLEDs, there is only moderate performance reported for blue PeLEDs, [11-18] which undoubtedly restrict PeLED applications in full-color displays and white-light illumination. Thus, the breakthroughs of the device performance are urgently required for blue PeLEDs. Substantial efforts have been made in the past several years to obtain blue perovskite emitters, such as perovskite nanocrystals (NCs), [19-25] 2D perovskite nanoplatelets, [26-32] and quasi-2D perovskites. [33-39] In particular, the quasi-2D perovskites are rising as efficient luminescent materials for highly performed blue PeLEDs due to the cascade energy landscape for efficient exciton transfer and the subsequent radiative recombination. Typically, the quasi-2D perovskites have a formula of B 2 (APbBr 3) n−1 PbBr 4 , While there has been extensive investigation into modulating quasi-2D perovskite compositions in light-emitting diodes (LEDs) for promoting their electroluminescence, very few reports have studied approaches involving enhancement of the energy transfer between quasi-2D perovskite layers of the film, which plays very important role for achieving high-performance perovskite LEDs (PeLEDs). In this work, a bifunctional ligand of 4-(2-aminoethyl)benzoic acid (ABA) cation is strategically introduced into the perovskite to diminish the weak van der Waals gap between individual perovskite layers for promoting coupled quasi-2D perovskite layers. In particular, the strengthened interaction between coupled quasi-2D perovskite layers favors an efficient energy transfer in the perovskite films. The introduced ABA can also simultaneously passivate the perovskite defects by reducing metallic Pb for less nonradiative recombination loss. Benefiting from the advanced properties of ABA incorporated perovskites, highly efficient blue PeLEDs with external quantum efficiency of 10.11% and a very long operational stability of 81.3 min, among the best performing blue quasi-2D PeLEDs, are achieved. Consequently, this work contributes an effective approach for high-performance and stable blue PeLEDs toward practical applications. Metal halide perovskites have emerged as competitive candidates for the next-generation light-emitting diodes (LEDs) due to their excellent optical properties, such as tunable light emission color, high color purity, and high photoluminescence The ORCID identification number(s) for the author(s) of this article can be found under

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Section: Figurementioning

confidence: 99%

High‐Performance Blue Perovskite Light‐Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi‐2D Perovskite Layers

et al. 2020

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“…Taking into account the morphology changes (Figure 1b), the prolonged PL lifetime, and reduced trap densities demonstrate the suppression of trap‐assisted non‐radiative recombination losses for the perovskite film on the K + ‐modified PEDOT:PSS. [ 13,30,48 ]…”

Section: Resultsmentioning

confidence: 99%

Interfacial Potassium‐Guided Grain Growth for Efficient Deep‐Blue Perovskite Light‐Emitting Diodes

Shen

et al. 2020

Adv Funct Materials

118

132

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Perovskite light‐emitting diodes (PeLEDs) are emerging candidates for the applications of solution‐processed full‐color displays. However, the device performance of deep‐blue PeLED still lags far behind that of their red and green counterparts, which is largely limited by low external quantum efficiency (EQE) and poor operational stability. Here, a facile and reliable crystallization strategy for perovskite grains is proposed, with improved deep‐blue emission through rational interfacial engineering. By modifying the substrate with potassium cation (K+) as the supplier of heterogeneous nucleation seeds, the interfacial K+‐guided grain growth is realized for well‐packed perovskite assemblies with high surface coverage and the controlled crystal orientation, leading to the enhanced radiative recombination and hole‐transport capabilities. Synergistical boost in device performance is achieved for deep‐blue PeLEDs emitting at 469 nm with a peak EQE of 4.14%, a maximum luminance of 451 cd m–2, and spectrally stable color coordinates of (0.125, 0.076) that matches well with the National Television System Committee (NTSC) standard blue.

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“…Quaternary ammonium halides have become ubiquitous ligands for CsPbBr 3 NCs, [37,41,44,67,72,[85][86][87] representing an upgrade on the initial amine ligands. Quaternary ammonium halides contain the same binding functionality that a primary amine provides, but are unable to participate in proton exchange.…”

Section: Quaternary Ammonium Halidesmentioning

confidence: 99%

“…The application of crown ethers to coordinate metal ions for perovskite NC synthesis is an interesting approach. Besides obvious extensions of Veldhuis and co-workers' efforts (e.g., solubilizing other alkali metal ions such as Rb + or K + for A-site doping or passivation), [77,79,87,[98][99][100] the selectivity of crown ether coordination may allow the direct synthesis of transition metal-doped CsPbX 3 NCs at room temperature by coordinating Pb 2+ . [101] Crown ethers coordinate more strongly to metal ions with an ionic radius close to their cavity size, thus selecting the appropriate crown ether for Pb 2+ could impede the formation of the thermodynamically favored pure CsPbX 3 perovskite, allowing smaller dopant metal ions to occupy some lead sites.…”

Section: Metal Dopingmentioning

confidence: 99%

Lead Halide Perovskite Nanocrystals: Room Temperature Syntheses toward Commercial Viability

Brown

Bahulayan

Jiang

et al. 2020

Advanced Energy Materials

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In this progress report, recent improvements to the room temperaturesyntheses of lead halide perovskite nanocrystals (APbX3, X = Cl, Br, I) are assessed, focusing on various aspects which influence the commercial viability of the technology. Perovskite nanocrystals can be prepared easily from low‐cost precursors under ambient conditions, yet they have displayed near‐unity photoluminescence quantum yield with narrow, highly tunable emission peaks. In addition to their impressive ambipolar charge carrier mobilities, these properties make lead halide perovskite nanocrystals very attractive for light‐emitting diode (LED) applications. However, there are still many practical hurdles preventing commercialization. Recent developments in room temperature synthesis and purification protocols are reviewed, closely evaluating the suitability of particular techniques for industry. This is followed by an assessment of the wide range of ligands deployed on perovskite nanocrystal surfaces, analyzing their impact on colloidal stability, as well as LED efficiency. Based on these observations, a perspective on important future research directions that can expedite the industrial adoption of perovskite nanocrystals is provided.

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Efficient and Spectrally Stable Blue Perovskite Light‐Emitting Diodes Based on Potassium Passivated Nanocrystals

Cited by 154 publications

References 50 publications

High‐Performance Blue Perovskite Light‐Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi‐2D Perovskite Layers

High‐Performance Blue Perovskite Light‐Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi‐2D Perovskite Layers

Interfacial Potassium‐Guided Grain Growth for Efficient Deep‐Blue Perovskite Light‐Emitting Diodes

Lead Halide Perovskite Nanocrystals: Room Temperature Syntheses toward Commercial Viability

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