SCIENCE CHINA Materials, Volume 62, Issue 2: 225-235(2019) https://doi.org/10.1007/s40843-018-9311-9

High-performance flexible and broadband photodetectors based on PbS quantum dots/ZnO nanoparticles heterostructure

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  • ReceivedApr 24, 2018
  • AcceptedJun 8, 2018
  • PublishedJun 28, 2018


Flexible and broadband photodetectors have drawn extensive attention due to their potential application in foldable displays, optical communications, environmental monitoring, etc. In this work, a flexible photodetector based on the crystalline PbS quantum dots (QDs)/ZnO nanoparticles (NPs) heterostructure was proposed. The photodetector exhibits a broadband response from ultraviolet-visible (UV-Vis) to near infrared detector (NIR) range with a remarkable current on/off ratio of 7.08×103 under 375 nm light illumination. Compared with pure ZnO NPs, the heterostructure photodetector shows the three orders of magnitude higher responsivity in Vis and NIR range, and maintains its performance in the UV range simultaneously. The photodetector demonstrates a high responsivity and detectivity of 4.54 A W−1 and 3.98×1012 Jones. In addition, the flexible photodetectors exhibit excellent durability and stability even after hundreds of times bending. This work paves a promising way for constructing next-generation high-performance flexible and broadband optoelectronic devices.

Funded by

Collaborative Innovation Center of Suzhou Nano Science & Technology and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices. Wen Z thanks the support from China Postdoctoral Science Foundation(2017M610346)

Natural Science Foundation of Jiangsu Province of China(BK20170343)


The work was funded by the National Natural Science Foundation of China (U1432249), the National Key R&D Program of China (2017YFA0205002), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). This is also a project supported by Collaborative Innovation Center of Suzhou Nano Science & Technology and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices. Wen Z thanks the support from China Postdoctoral Science Foundation (2017M610346) and Natural Science Foundation of Jiangsu Province of China (BK20170343).

Interest statement

The authors declare no conflict of interest.

Contributions statement

Peng M, Wang Y and Shen Q have contributed equally to this work. Peng M designed and fabricated the devices. Wang Y synthesized the nanomaterials. Shen Q, Xie X and Zheng H performed the structure and morphology characterization. Peng M wrote the paper with support from Ma W, Wen Z and Sun X. All authors contributed to the experiment data discussion.

Author information

Mingfa Peng received his BSc degree in materials chemistry from Hubei Engineering University in 2008 and MSc degree in materials science from Soochow University in 2011, respectively. He is currently a PhD candidate in the Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University. His research focuses primarily on nanomaterial-based device fabrication and self-powered active photodetector.

Zhen Wen received his BSc degree in materials science and engineering from China University of Mining and Technology (CUMT) in 2011 and PhD degree in materials physics and chemistry from Zhejiang University (ZJU) in 2016. During 2014–2016, he was supported by the program of China Scholarship Council (CSC) as a joint PhD student in Georgia Institute of Technology (GT). He joined in the Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University as an assistant professor since the end of 2016. His main research interest focuses on triboelectric nanogenerator based energy harvesting and self-powered sensing system.

Xuhui Sun is a full professor at the Institute of Functional Nano & Soft Materials (FUNSOM) at Soochow University. He received his PhD degree from the City University of Hong Kong in 2002. He performed postdoctoral research at the University of Western Ontario, Canada from 2003 to 2005 and at NASA Ames Research Center, USA from 2005 to 2007. He became a research scientist at NASA and adjunct assistant professor at Santa Clara University in 2007. His research interest includes nanoelectronics, energy harvesting, nanosensors, and the development and application of synchrotron radiation techniques.


Supplementary information

Supporting data are available in the online version of the paper.


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  • Figure 1

    Fabrication the process and characterization of PbS quantum dots (QDs)/ZnO nanoparticles (NPs) heterostructure based photodetector. (a) Schematic illustration of fabrication process of the flexible device. HRTEM image of the as-synthesized (b) ZnO NPs and (c) PbS QDs. (d) XRD spectra of PbS, ZnO and PbS/ZnO heterostructure.

  • Figure 2

    Characterization and performance of the PbS QDs/ZnO NPs heterostructure based photodetector. (a) Schematic view of the two-terminal contact flexible photodetector. (b) UV-Vis spectra of ZnO NPs, PbS QDs/ZnO NPs and PbS QDs. (c) I–V curve of the PbS/ZnO heterostructure based photodetector under different-wavelength lights or dark conditions. (d) The Ilight/Idark ratio and responsivity of PbS/ZnO heterostructure based photodetector at different wavelengths from 375 to 1,064 nm at a bias of 5 V. (e) The time-resolved photoresponse of the flexible photodetector under 375, 532 and 808 nm light illumination. (f) The rise time and decay time of the photodetector under 375, 532 and 808 nm light illumination, respectively.

  • Figure 3

    Photoelectric performance comparison for the photodetectors. (a) The responsivity, and (b) detectivity for PbS QDs/ZnO NPs and pure ZnO NPs photodetectors under different wavelength light illumination at 5 V bias.

  • Figure 4

    Typical performance of the PbS/ZnO heterostructure based photodetectors. I–V curves of the photodetector under (a) 375 nm, (c) 532 nm, and (e) 808 nm light with different light intensity illumination, respectively. The photocurrent and responsivity under (b) 375 nm, (d) 532 nm, and (f) 808 nm light as function of light intensity.

  • Figure 5

    The bending performance of the PbS QDs/ZnO NPs heterostructure based flexible photodetector. (a) Relationship between photocurrent and different bending degree. I–V curves of flexible photodetector under (b) 375 nm, (c) 532 nm and (d) 808 nm light illumination without bending and after 100, 200, 300, 400 and 500 times bending. The I–t curves of the flexible photodetector under (e) 375 nm, (f) 532 nm and (g) 808 nm light illumination without and after different times bending.

  • Figure 6

    Enhancement mechanism of the PbS QDs/ZnO NPs heterostructure based photodetector. (a) Photoluminescence measured for PbS and PbS/ZnO heterostructure. Energy bandgap diagrams of the PbS/ZnO heterostructure under light illumination (b) before and (c) after contact.

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