ENGINEERING TECHNOLOGY

Professor Jiang Maowei/Professor Wang Feijiu of Henan University: Modify the buried interface and light up PeLED!


April 24, 2023, Henan UniversityJiang MaoweiprofessorWang FeijiuProfessor in the Action Plan for Excellence in Chinese Science and Technology JournalsHigh starting point new issueNano Research Energy The latest research results entitled “Enabling monodisperse perovskite phase with buried interface modification toward efficient light-emitting diodes” were published.

Semiconductor perovskite light-emitting diodes (PeLEDs)It exhibits excellent electroluminescence properties (such as high color purity, high electro-optical energy conversion efficiency, etc.) and simple solution processability, which has aroused the research boom of scholars. In PeLED applications, for enhanced injectionElectron-hole pairsAt the radiation recombination rate, the researchers established a perovskite nanocrystalline thin film system, which is composed of small-size nanocrystals or low-dimensional quantum hydrazine (such as quasi-two-dimensional quasi-2D perovskite structure), which can effectively improve the luminescence performance of PeLED. However, such perovskite nanocrystalline films tend to exhibit phase polydispersity. Especially in the presence ofQuantum confinement effect(such as quantum hydrazine or quantum dots), the polydisperse phase corresponds to the inhomogeneous grain band gap and exciton energy distribution; The energy funnel effect between different bandgap grains can induce energy transfer of excitons between dispersed phases of chaotic distribution, and this process can lead to unnecessary loss of radiated energy. Therefore, the optimal regulation of polydisperse phases in perovskite nanocrystalline films to inhibit energy transfer between polydisperse phases has become one of the key issues affecting the performance of PeLED. The crystallization process of perovskites is affected byBury interface featuresTherefore, it is particularly important to start the buried interface modification of perovskite films and study the crystallization regulation of monodisperse perovskite nanocrystalline films. In addition, the trap state also intrinsically exists at the buried interface of the perovskite film, which causes non-radiative recombination of electron holes injected, which reduces the performance of PeLED. Effective passivation of perovskite film defects at the buried interface is an inevitable way to obtain high-performance PeLEDs.

In response to the above problems,Jiang MaoweiandWang FeijiuFaculty team adoptionLiBr modified perovskite burial interface。 The authors confirmed that the LiBr pre-modified layer can effectively regulate the crystallization process of perovskite and induce the formation of monodisperse perovskite nanocrystals. In this system, larger and smaller perovskite nanocrystals are effectively suppressed, resulting in a more uniform size perovskite nanocrystalline film, that is, an enhanced monodisperse phase. The nanocrystalline size distribution narrows, exhibiting a smaller fluorescence half-peak width (18 nm), corresponding to higher color purity. Compared with the control group, the carrier transfer process derived from the polydisperse phase was effectively inhibited, and the direct radiation recombination process was strengthened. In addition, the LiBr modification layer at the buried interface can directly fill the halogen (Br-) vacancy of the perovskite and passivate the Pb ion defect, thereby minimizing the generation of trap states and enhancing the radiation recombination of the perovskite. After the above research, the authors obtained high-performance PeLEDs, which are used in 4 mm2Manifested in small devices 25.5% Excellent external quantum efficiency (EQE), in 100 mm2Exhibited in large-area devices 22.9% excellent performance.

Paper Information:

Jiang M, Zhang X, Wang F. Enabling monodisperse perovskite phase with buried interface modification toward efficient light-emitting diodes. Nano Research Energy, 2023, https://doi.org/10.26599/NRE.2023.9120069

DOI:10.26599/NRE.2023.9120069

Nano Research Energy is a companion journal of Nano Research, (ISSN: 2791-0091; e-ISSN: 2790-8119; Official Website: https://www.sciopen.com/journal/2790-8119Founded in June 2022, Professor Qu Liangti of Tsinghua University and Professor Chunyi Zhi of City University of Hong Kong serve as editors-in-chief.Nano Research EnergyIt is an international multidisciplinary and English-based open access journal, focusing on the cutting-edge research and application of nanomaterials and nanoscience and technology in new energy-related fields, benchmarking against top international energy journals, and committed to publishing high-level original research and review papers, which has been selected2022 China Science and Technology Journals Excellence Action Plan – High Starting Point New Journal Project。 APC fees will be waived until 2025, and teachers are welcome to submit their papers.

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NanoResearchEnergy@tup.tsinghua.edu.cn

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