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Wang C, Chen Z, Liu Z, Ma T, Chen X, Zhang M, Luo D, Hyun BR, Liu X. Adjusting Microscale to Atomic-Scale Structural Order in PbS Nanocrystal Superlattice for Enhanced Photodetector Performance. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300975. [PMID: 37066743 DOI: 10.1002/smll.202300975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/20/2023] [Indexed: 06/19/2023]
Abstract
An investigation is presented into the effect of the long-range order on the optoelectronic properties of PbS quantum dot (QD) superlattices, which form mesocrystals, for potential use in photodetector applications. By self-assembly of QD nanocrystals on an Si/SiOx substrate, a highly ordered and densely packed PbS QD superlattice with a microscale size is obtained. The results demonstrate that annealing treatment induces mesocrystalline superlattices with preferred growth orientation, achieved by dislodging ligands. The improved orientation and electronic coupling of the mesocrystalline superlattices exhibit superior photodetector performance compared to disordered QD structures and closely packed superlattices. This improved performance is attributed to atomic alignment between QDs, leading to enhanced electronic coupling. The findings suggest that these mesocrystalline superlattices have promising potential for the next generation of QD optoelectronic devices.
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Affiliation(s)
- Chuanglei Wang
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Zhenjun Chen
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Zheng Liu
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Tianchan Ma
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Xiya Chen
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Menglong Zhang
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Dongxiang Luo
- Huangpu Hydrogen Innovation Center/Guangzhou Key Laboratory for Clean Energy and Materials, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, 510006, P. R. China
| | - Byung-Ryool Hyun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Xiao Liu
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
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Quantitatively controlled electrophoretic deposition of nanocrystal films from non-aqueous suspensions. J Colloid Interface Sci 2023; 636:363-377. [PMID: 36638575 DOI: 10.1016/j.jcis.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/14/2022] [Accepted: 01/02/2023] [Indexed: 01/08/2023]
Abstract
This study presents a novel method to correlate the mass and charge transfer kinetics during the electrophoretic deposition of nanocrystal films by using a purpose-built double quartz crystal microbalance combined with simultaneous current-measurement. Our data support a multistep process for film formation: generation of charged nanocrystal flux, charge transfer at the electrode, and polarization of neutral nanocrystals near the electrode surface. The polarized particles are then subject to dielectrophoretic forces that reduce diffusion away from the interface, generating a sufficiently high neutral particle concentration at the interface to form a film. The correlation of mass and charge transfer enables quantification of the nanocrystal charge, the fraction of charged nanocrystals, and the initial sticking coefficient of the particles. These quantities permit calculation of the film thickness, providing a theoretical basis for using concentration and voltage as process parameters to grow films of targeted thicknesses.
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