Aggregation Control, Surface Passivation, and Optimization of Device Structure toward Near-Infrared Perovskite Quantum-Dot Light-Emitting Diodes with an EQE up to 15.4

Zong-Liang Tseng; Lung-Chien Chen; Li-Wei Chao; Meng-Ju Tsai; Dian Luo; Nurul Ridho Al Amin; Shun-Wei Liu; Ken-Tsung Wong

doi:10.1002/adma.202109785

Aggregation Control, Surface Passivation, and Optimization of Device Structure toward Near-Infrared Perovskite Quantum-Dot Light-Emitting Diodes with an EQE up to 15.4

Adv Mater. 2022 May;34(18):e2109785. doi: 10.1002/adma.202109785. Epub 2022 Mar 27.

Authors

Zong-Liang Tseng^{1

2}, Lung-Chien Chen³, Li-Wei Chao³, Meng-Ju Tsai⁴, Dian Luo², Nurul Ridho Al Amin², Shun-Wei Liu^{1

2}, Ken-Tsung Wong^{4

5}

Affiliations

¹ Department of Electronic Engineering, Ming Chi University of Technology, New Taipei City, 24301, Taiwan.
² Organic Electronics Research Center, Ming Chi University of Technology, New Taipei City, 24301, Taiwan.
³ Department of Electro-Optical Engineering, National Taipei University of Technology, Taipei, 106344, Taiwan.
⁴ Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
⁵ Institute of Atomic and Molecular Science, Academia Sinica, Taipei, 10617, Taiwan.

PMID: 35245396
DOI: 10.1002/adma.202109785

Abstract

In recent years, the performance of perovskite quantum dots (QDs) and QD-based light-emitting diodes (QLEDs) has improved greatly, with electroluminescence (EL) efficiency of green and red emission exceeding 20%. However, the development of perovskite near-infrared (NIR) QLEDs has reached stagnation, where the reported maximum EL efficiency is still below 6%, limiting their further applications. In this work, new NIR-emissive FAPbI₃ QDs are developed by post-treating long alkyl-encapsulated QDs with 2-phenylethylammonium iodide (PEAI). The incorporation of PEAI reduces the QD surface defects for giving a high photoluminescence quantum yield up to 61.6%. The n-octane solution of PEAI-passivated FAPbI₃ QDs is spin coated on top of the PEDOT:PSS-treated ITO electrode modified with a thermally crosslinked hole-transporting layer to give a full-coverage, smooth, and dense QD film. Incorporating with an effective electron-transporting material, CN-T2T, which has deep lowest unoccupied molecular orbital and good electron mobility, the optimal device with EL λ_max at 772 nm achieves an external quantum efficiency up to 15.4% at a current density of 0.54 mA cm^-2 (2.6 V), which is the highest efficiency ever reported for perovskite-based NIR QLEDs. This study provides a facile strategy to prepare high-quality perovskite QD films suitable for highly efficient NIR QLED applications.

Keywords: near-infrared emission; perovskites; quantum dots; quantum-dot light-emitting diodes.

Abstract

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