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In situ interface engineering for probing the limit of quantum dot photovoltaic devices


Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust ‘nanolab’ platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells.

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Fig. 1: Configuration and performance of a single nanowire QDHSC.
Fig. 2: Enhanced absorption efficiency of a TiO2-nanowire QDHSC.
Fig. 3: The dependence of the photocurrent on the interface area.
Fig. 4: The effect of interface area on the open voltage and the efficiency of a single nanowire QDHSC.
Fig. 5: The mechanism of high efficiency and comparison of single nanowire QDHSCs.

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Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


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This research was supported by National Key Research and Development Program of China (2017YFA0204800), the Natural National Science Foundation of China (Grant nos. 11327901, 11525415, 51420105003, 61106055, 11774051, 61574034 and 61601116), the National Basic Research Program of China (2015CB352106), the Fundamental Research Funds for the Central Universities (2242018K41020). Z.S. appreciates the financial support from the Australian Research Council (ARC) through an ARC Future Fellowship project (FT180100387) and a Discovery Project (DP160102627).

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Authors and Affiliations



H.D., F.X., Z.Z. and L.S. conceived and designed the experiments. H.D. performed the experiments. H.D., Z.S., L.S., Z.Z. and X.D. analysed the data and constructed the paper. Y.Z. performed the finite‐difference time‐domain simulation. L.S. contributed materials and analysis tools. H.D. and Z.S. co-wrote the paper with all the authors contributing to the discussion and preparation of the manuscript.

Corresponding authors

Correspondence to Ze Zhang, Xiangfeng Duan or Litao Sun.

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The authors declare no competing interests.

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Peer review information: Nature Nanotechnology thanks Giorgio Divitini and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–36 and refs. 1–11.

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Dong, H., Xu, F., Sun, Z. et al. In situ interface engineering for probing the limit of quantum dot photovoltaic devices. Nat. Nanotechnol. 14, 950–956 (2019).

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