Ultra-low EQE roll-off and marvelous efficiency perovskite quantum-dots light-emitting-diodes achieved by ligand passivation

Ye, Yuliang; Wang, Jiaxiang; Qiu, Yinglin; Liu, Jiahui; Ye, Bingqing; Yang, Zunxian; Gong, Zhipeng; Xu, Lei; Zhou, Yuanqing; Huang, Qiaocan; Shen, Zihong; Wu, Wenbo; Ju, Songman; Yu, Lucheng; Fu, Yihang; Li, Fushan; Prof., Tailiang Guo

doi:10.1016/j.nanoen.2021.106583

Cited by 28 publications

(20 citation statements)

References 43 publications

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“…The pristine colloidal PNCs are synthesized based on our reported work . As shown in Figure S1, ZnBr 2 cannot dissolve in toluene at room temperature, but the introduction of DDAB assists its solubility in toluene, avoiding the usage of polar solvent commonly.…”

Section: Resultsmentioning

confidence: 99%

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Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Hou

Chen

et al. 2023

Langmuir

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Oleylamine/oleic acid (OAm/OA) as the commonly used ligand is indispensable in the synthesis of perovskite nanocrystals (PNCs). Unfortunately, poor colloidal stability and unsatisfactory photoluminescence quantum yield (PLQY) are observed, resulting from a highly dynamic binding nature between ligands. Herein, we adopt a facile hybrid ligand (DDAB/ZnBr 2 ) passivation strategy to reconstruct the surface chemistry of CsPbBr 3 NCs. The hybrid ligand can detach the native surface ligand, in which the acid−base reactions between ligands are suppressed effectively. Also, they can substitute the loose capping ligand, anchor to the surface firmly, and supply sufficient halogens to passivate the surface trap, realizing an exceptional PLQY of 95% and an enhanced tolerance toward ambient storage, UV irradiation, anti-solvents, and thermal treatment. Besides, the as-fabricated white light-emitting diode (WLED) utilizing the PNCs as the green-emitting phosphor has a luminous efficiency around 73 lm/W; the color gamut covers 125% of the NTSC standard.

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Section: Resultsmentioning

confidence: 99%

“…For example, because of additional binding groups, bidentate ligands , or zwitterionic ligands , with high affinity can bind to the surface tightly. According to the soft–hard acid–base theory, softer acids, such as phosphonic acid , and sulfonic acid, − are expected to possess a higher affinity to Pb 2+ .…”

Section: Introductionmentioning

confidence: 99%

Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Hou

Chen

et al. 2023

Langmuir

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“…For the solution samples of QDs, a biexponential decay function was usually used to fit the TRPL decay. The fast decay lifetime τ 1 was related to the nonradiative recombination process, and the slow decay lifetime τ 2 was related to the radiative recombination process. , As listed in Table , the exact values of the characteristic decay lifetimes τ 1 and τ 2 and the computed outcome τ avg of the different QDs were obtained in detail. After comparing the lifetimes of the two quantum dots, it could be observable that as compared with S-OA, the τ 1 of S-OT decreased, whereas the τ 2 increased, indicating that the optimized quantum dots reduced nonradiative recombination and increased recombination radiation.…”

Section: Resultsmentioning

confidence: 99%

Performance Enhancement of Quantum Dot Light-Emitting Diodes via Surface Modification of the Emitting Layer

Qiu

Gong

et al. 2022

ACS Appl. Nano Mater.

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CdSe-based quantum dots (QDs) have increasingly become important QDs for emerging display material because of their suitable bandgap, controllable size, and high PLQY. However, there are still many problems with CdSe QD films, including severe fluorescence quenching and low conductivity. Herein, we replace the long insulated oleic acid ligand with the shorter thiol ligand to enhance the mobility of charge carriers. It was found that the QDs with octanethiol in a quantum dot light-emitting diode (QLED) exhibited higher conductivity and lower turn-on voltage. Moreover, the defects on the surface of the QD layer were effectively passivated by adding a thin layer of cesium carbonate, and the radiation recombination of the quantum dot light-emitting layer was also significantly improved. It was evident that the performance of the optimized QLED device was improved with a peak luminance of 166 300−294 500 cd/m 2 and a peak current efficiency of 10−32 cd/A. Thus, the current work provides two ways to optimize QD films and proposes a method to improve the performance of QLEDs.

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“…It is wellknown that the residual charges roughly consist of charges in trap sites and accumulated at interfaces adjacent to the emissive layer. 46 Most of the charges accumulated at interfaces will recombine by emitting photons or other non-radiative recombination processes. In contrast, the charges in the trap sites will affect the charge transport processes significantly.…”

Section: Resultsmentioning

confidence: 99%

“…Another attention that must be paid is the influence of the residual charges in the devices on the EL delay time. It is well-known that the residual charges roughly consist of charges in trap sites and accumulated at interfaces adjacent to the emissive layer . Most of the charges accumulated at interfaces will recombine by emitting photons or other non-radiative recombination processes.…”

Section: Resultsmentioning

confidence: 99%

Calibrating the Hole Mobility Measurements Implemented by Transient Electroluminescence Technology

Zhu

Bai

et al. 2022

ACS Appl. Mater. Interfaces

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To date, measuring the carrier mobility in semiconductor films, especially for the amorphous organic small-molecule films, is still a big challenge. Here, we demonstrate that transient electroluminescence (TrEL) spectroscopy with quantum-dot light-emitting diodes as the platform is a feasible and reliable method to evaluate the carrier mobility of such amorphous films. The position of the exciton formation zone is precisely determined and controlled by employing a quantum dot monolayer as the emissive layer. The electrical field intensity across the organic layer is evaluated through the charge density at the electrode calculated by the transient current. Then, the charge carrier mobility is obtained by combining the electroluminescence (EL) delay time and the thickness of the organic layer. Additionally, we demonstrate that the large roughness of the organic layer leads to serious charge accumulation and, hence, a high localized electrical field, which provides preferred charge injection paths, reducing the EL delay time and underestimating the EL delay time. Therefore, a thick organic film is the prerequisite for a reliable measurement of charge carrier mobility, which can circumvent the negative effect of film roughness.

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Ultra-low EQE roll-off and marvelous efficiency perovskite quantum-dots light-emitting-diodes achieved by ligand passivation

Cited by 28 publications

References 43 publications

Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Performance Enhancement of Quantum Dot Light-Emitting Diodes via Surface Modification of the Emitting Layer

Calibrating the Hole Mobility Measurements Implemented by Transient Electroluminescence Technology

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Ultra-low EQE roll-off and marvelous efficiency perovskite quantum-dots light-emitting-diodes achieved by ligand passivation

Cited by 28 publications

References 43 publications

Surface Reconstruction of CsPbBr3 Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Surface Reconstruction of CsPbBr3 Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Performance Enhancement of Quantum Dot Light-Emitting Diodes via Surface Modification of the Emitting Layer

Calibrating the Hole Mobility Measurements Implemented by Transient Electroluminescence Technology

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Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability

Surface Reconstruction of CsPbBr₃ Nanocrystals by the Ligand Engineering Approach for Achieving High Quantum Yield and Improved Stability