50‐Fold EQE Improvement up to 6.27% of Solution‐Processed All‐Inorganic Perovskite CsPbBr<sub>3</sub> QLEDs via Surface Ligand Density Control

Li, Jianhai; Xu, Leimeng; Wang, Tao; Song, Jizhong; Chen, Jiawei; Xue, Jie; Dong, Yue; Cai, Bo; Shan, Qingsong; Han, Bin; Zeng, Haibo

doi:10.1002/adma.201603885

Cited by 1,020 publications

(999 citation statements)

References 40 publications

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“…TGA analysis shows that the weight loss of the CsPbBr 3 , TiO x , and CsPbBr 3 /TiO x samples proceeded in stages with temperature under argon flow (Figure 2a). There is only about 5% weight loss for CsPbBr 3 NCs between 30 and 500 °C, which is attributed to the removal of the surface organic ligands, [18] followed by fast weight loss above 500 °C due to sample decomposition. For CsPbBr 3 / TiO x composite, about ≈9% weight loss occurred from 30 to 150 °C, which corresponds to the evaporation of the water.…”

Section: Resultsmentioning

confidence: 99%

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Hofman

et al. 2017

Adv Funct Materials

440

413

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Inherent poor stability of perovskite nanocrystals (NCs) is the main impediment preventing broad applications of the materials. Here, TiO 2 shell coated CsPbBr 3 core/shell NCs are synthesized through the encapsulation of colloidal CsPbBr 3 NCs with titanium precursor, followed by calcination at 300 °C. The nearly monodispersed CsPbBr 3 /TiO 2 core/shell NCs show excellent water stability for at least three months with the size, structure, morphology, and optical properties remaining identical, which represent the most water-stable inorganic shell passivated perovskite NCs reported to date. In addition, TiO 2 shell coating can effectively suppress anion exchange and photodegradation, therefore dramatically improving the chemical stability and photostability of the core CsPbBr 3 NCs. More importantly, photoluminescence and (photo)electrochemical characterizations exhibit increased charge separation efficiency due to the electrical conductivity of the TiO 2 shell, hence leading to an improved photoelectric activity in water. This study opens new possibilities for optoelectronic and photocatalytic applications of perovskites-based NCs in aqueous phase.

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Section: Resultsmentioning

confidence: 99%

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Hofman

et al. 2017

Adv Funct Materials

440

413

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“…1 These NCs exhibit a high photoluminescence (PL) quantum yield (QY) of nearly 100%, 2–4 a narrow emission line-width and a wide color gamut. They are widely applied in solar cells, 5–9 LEDs 10–16 and lasing. 17,18 However, compared to the traditional cadmium chalcogenide quantum dots, 19–21 CsPbX 3 NCs showed poor colloidal stability during purification procedures and storage.…”

Section: Introductionmentioning

confidence: 99%

Surface ligand modification of cesium lead bromide nanocrystals for improved light-emitting performance

Zhang

et al. 2018

Nanoscale

122

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Cesium lead halide perovskite nanocrystals (NCs) possess excellent optical properties at visible wavelengths with great promise for applications in luminous display fields. We demonstrate a method to modify the surface ligand passivation of perovskite NCs for enhanced colloidal stability and emitting properties by incorporating didodecyl dimethyl ammonium bromide (DDAB). The photoluminescence quantum yield of the NC solution was improved to 96% from 70% and the perovskite film showed fewer trapped sites and enhanced carrier transport ability. The thus fabricated electroluminescent perovskite NC-LEDs exhibited a bright luminance of 11 990 cd m−2, corresponding to 4-times improved external quantum efficiency (EQE), compared to the control device using regular NCs without DDAB.

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“…[7] Colloidal quantum dots (QDs) such as CdSe, [8,9] InP, [10] and PbS [11] have been regarded as a new class of luminescent materials due to their high chemical stability, high PL QY, and tunable emission wavelengths which can easily cover the whole visible region by varying their size or dimension. [22][23][24][25][26][27][28][29] Despite these advantages of PQDs, the intrinsic instability and poor durability of the perovskite severely hamper the practical applications, which causes a huge technical obstacle for commercialization. [12][13][14][15][16][17][18][19][20][21] The high quantum efficiency, high color purity, and facile preparation make them as promising candidates for LED or backlight downconverters for LCDs.…”

Section: Introductionmentioning

confidence: 99%

Highly Luminescent Lead Halide Perovskite Quantum Dots in Hierarchical CaF₂ Matrices with Enhanced Stability as Phosphors for White Light‐Emitting Diodes

Wei

Xiao

Xie

et al. 2018

Advanced Optical Materials

114

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Lead halide perovskite quantum dots (PQDs) have been widely recognized as highly luminescent materials for efficient optoelectronic applications owing to their fascinating electronic and optical properties. In spite of the excellent performances for the fabrication of lighting devices, the poor chemical instability greatly hampers their practical applications. The inevitable ion exchange and degradation driven from light, moisture, heat, and others limits their applications such as solid‐state light‐emitting diodes (LEDs). In this paper, the stability of PQDs is improved by integrating them in CaF2 hierarchical nanospheres (HNSs). In comparison with the pristine perovskite materials, the outstanding optical performances are well preserved. The perovskite displays a unique quantum confinement effect in the HNSs. Additionally, embedding the quantum dots in robust CaF2 matrices protects them from being damaged by moisture or light irradiation as well as anion exchange. Furthermore, white LED devices are obtained by mixing green CaF2‐CsPbBr3 composites and commercial red phosphors on a blue chip. The optimized devices show a high luminous efficacy of 62.7 lm W–1 under 20 mA current and preserve the value of 56.3 lm W–1 after working for 8 h.

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50‐Fold EQE Improvement up to 6.27% of Solution‐Processed All‐Inorganic Perovskite CsPbBr₃ QLEDs via Surface Ligand Density Control

Cited by 1,020 publications

References 40 publications

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Surface ligand modification of cesium lead bromide nanocrystals for improved light-emitting performance

Highly Luminescent Lead Halide Perovskite Quantum Dots in Hierarchical CaF₂ Matrices with Enhanced Stability as Phosphors for White Light‐Emitting Diodes

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50‐Fold EQE Improvement up to 6.27% of Solution‐Processed All‐Inorganic Perovskite CsPbBr3 QLEDs via Surface Ligand Density Control

Cited by 1,020 publications

References 40 publications

Photoelectrochemically Active and Environmentally Stable CsPbBr3/TiO2 Core/Shell Nanocrystals

Photoelectrochemically Active and Environmentally Stable CsPbBr3/TiO2 Core/Shell Nanocrystals

Surface ligand modification of cesium lead bromide nanocrystals for improved light-emitting performance

Highly Luminescent Lead Halide Perovskite Quantum Dots in Hierarchical CaF2 Matrices with Enhanced Stability as Phosphors for White Light‐Emitting Diodes

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Product

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50‐Fold EQE Improvement up to 6.27% of Solution‐Processed All‐Inorganic Perovskite CsPbBr₃ QLEDs via Surface Ligand Density Control

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Highly Luminescent Lead Halide Perovskite Quantum Dots in Hierarchical CaF₂ Matrices with Enhanced Stability as Phosphors for White Light‐Emitting Diodes