Separating Crystal Growth from Nucleation Enables the In Situ Controllable Synthesis of Nanocrystals for Efficient Perovskite Light-Emitting Diodes

Wenjin Yu; Mingyang Wei; Zhenyu Tang; Hongshuai Zou; Liang Li; Yu Zou; Shuang Yang; Yunkun Wang; Yuqing Zhang; Xiangdong Li; Haoqing Guo; Cuncun Wu; Bo Qu; Yunan Gao; Guowei Lu; Shufeng Wang; Zhijian Chen; Zhiwei Liu; Huanping Zhou; Bin Wei; Yingjie Liao; Lijun Zhang; Yan Li; Qihuang Gong; Edward H Sargent; Lixin Xiao

doi:10.1002/adma.202301114

Separating Crystal Growth from Nucleation Enables the In Situ Controllable Synthesis of Nanocrystals for Efficient Perovskite Light-Emitting Diodes

Adv Mater. 2023 Aug;35(33):e2301114. doi: 10.1002/adma.202301114. Epub 2023 Jul 2.

Authors

Wenjin Yu¹, Mingyang Wei², Zhenyu Tang¹, Hongshuai Zou³, Liang Li⁴, Yu Zou¹, Shuang Yang¹, Yunkun Wang¹, Yuqing Zhang¹, Xiangdong Li¹, Haoqing Guo¹, Cuncun Wu¹, Bo Qu¹, Yunan Gao¹, Guowei Lu¹, Shufeng Wang^{1

5}, Zhijian Chen¹, Zhiwei Liu⁶, Huanping Zhou⁴, Bin Wei⁷, Yingjie Liao⁷, Lijun Zhang³, Yan Li^{1

5}, Qihuang Gong^{1

5}, Edward H Sargent², Lixin Xiao^{1

5}

Affiliations

¹ State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Department of Physics, Peking University, Beijing, 100871, P. R. China.
² Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, M5S 3G4, Canada.
³ State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Automobile Materials of MOE, Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials and School of Materials Science and Engineering, Jilin University, Changchun, 130012, P. R. China.
⁴ School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China.
⁵ Yangtze Delta Institute of Optoelectronics, Peking University, Nantong, 226010, P. R. China.
⁶ Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China.
⁷ Key Laboratory of Advanced Display and System Applications, Shanghai University, Shanghai, 200072, P. R. China.

PMID: 37314026
DOI: 10.1002/adma.202301114

Abstract

Colloidal perovskite nanocrystals (PNCs) display bright luminescence for light-emitting diode (LED) applications; however, they require post-synthesis ligand exchange that may cause surface degradation and defect formation. In situ-formed PNCs achieve improved surface passivation using a straightforward synthetic approach, but their LED performance at the green wavelength is not yet comparable with that of colloidal PNC devices. Here, it is found that the limitations of in situ-formed PNCs stem from uncontrolled formation kinetics: conventional surface ligands confine perovskite nuclei but fail to delay crystal growth. A bifunctional carboxylic-acid-containing ammonium hydrobromide ligand that separates crystal growth from nucleation is introduced, leading to the formation of quantum-confined PNC solids exhibiting a narrow size distribution. Controlled crystallization is further coupled with defect passivation using deprotonated phosphinates, enabling improvements in photoluminescence quantum yield to near unity. Green LEDs are fabricated with a maximum current efficiency of 109 cd A^-1 and an average external quantum efficiency of 22.5% across 25 devices, exceeding the performance of their colloidal PNC-based counterparts. A 45.6 h operating half-time is further documented for an unencapsulated device in N₂ with an initial brightness of 100 cd m^-2 .

Keywords: crystallization; in situ controllable synthesis; light-emitting diodes; nanocrystals; perovskites.

Abstract

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