Pressure-enhanced electronic coupling of highly passivated quantum dot films to improve photovoltaic performance

PbS colloidal quantum dot solar cells (CQDSCs) have recently achieved remarkable performance enhancement due to the development of the phase-transfer ligand exchange (PTLE) method. However, the lack of compact packing of the PTLE-passivated CQDs impairs the interdot electronic coupling and thereby s...

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Bibliographic Details
Published in:Applied physics letters 2019-11, Vol.115 (19)
Main Authors: Wang, Yinglin, An, Meiqi, Jia, Yuwen, Wang, Lei, Li, Jinhuan, Weng, Binbin, Zhang, Xintong, Liu, Yichun
Format: Article
Language:English
Subjects:
Applied physics
Carrier recombination
Carrier transport
Coupling
Electrical measurement
Energy conversion efficiency
External pressure
Maximum power
Optoelectronic devices
Performance enhancement
Photovoltaic cells
Quantum dots
Solar cells
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Summary:PbS colloidal quantum dot solar cells (CQDSCs) have recently achieved remarkable performance enhancement due to the development of the phase-transfer ligand exchange (PTLE) method. However, the lack of compact packing of the PTLE-passivated CQDs impairs the interdot electronic coupling and thereby severely restricts further improvement in performance. To address this electronic coupling issue, we report a simple yet effective process of external pressure (0–2 MPa). We find that the interdot distance is reduced after the application of the pressure. Both optical and electrical measurements clearly demonstrate that the distance reduction can effectively strengthen the interdot electronic coupling, thus promoting the carrier transport of the CQD layer. However, too much pressure (>2 MPa) could accelerate the detrimental carrier recombination processes of CQDSCs. Accordingly, by optimizing the carrier transport and recombination processes, we achieve the maximum power conversion efficiency of 8.2% with a moderate pressure of 1.5 MPa, which is 25.5% higher than the solar cell without the external pressure. This effective strategy of external pressure could also be applied to other CQD-based optoelectronic devices to realize a better device performance.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.5110749