Frontiers of Optoelectronics

, Volume 11, Issue 4, pp 360–366 | Cite as

High fill factor over 82% enabled by a biguanide doping electron transporting layer in planar perovskite solar cells

  • Ru Ge
  • Fei Qin
  • Lin Hu
  • Sixing Xiong
  • Yinhua ZhouEmail author
Research Article


N-type doping in electron transport materials is an effective way to improve the electron collection and enhance the performance of the perovskite solar cells (PSCs). Here, for the first time, an antibiotic and antimicrobial compound of 1-(o-Tolyl) biguanide (oTb) is used to dope the electron transport material of phenyl-C61-butyric acid methyl ester (PCBM). The oTb doping into the PCBM can increase the conductivity and reduce the work function of the PCBM. The oTb doping can significantly enhance the fill factor (FF) of the perovskite solar cells with the structure of glass/ITO/NiOx/MAPbI3/(oTb)PCBM/(PEIE)/Ag. For the cells without PEIE (polyethylenimine ethoxylated) coating, the oTb doping increases the FF from 0.57 to 0.73. S-shaped of the current density-voltage (J-V) characteristic under illumination is removed after the oTb doping. For the cells with PEIE coating between the (oTb)PCBM and Ag, the oTb doping increases the FF from 0.70 to 0.82. These results show the potential of the oTb as an n-dopant in the applications of perovskite solar cells.


perovskite solar cells n-doping biguanide fill factor (FF) electron transporting layer 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



The work was supported by the National Natural Science Foundation of China (Grant Nos. 21474035 and 51773072), the Recruitment Program of Global Youth Experts, the Huazhong University of Science and Technology (HUST) Innovation Research Fund (Nos. 2016JCTD111 and 2017KFKJXX012), the Science and Technology Program of Hubei Province (No. 2017AHB040) and China Postdoctoral Science Foundation funded project (No. 2016M602289).


  1. 1.
  2. 2.
    Polman A, Knight M, Garnett E C, Ehrler B, Sinke W C. Photovoltaic materials: present efficiencies and future challenges. Science, 2016, 352(6283): aad4424CrossRefGoogle Scholar
  3. 3.
    Correa-Baena J P, Saliba M, Buonassisi T, Grätzel M, Abate A, Tress W, Hagfeldt A. Promises and challenges of perovskite solar cells. Science, 2017, 358(6364): 739–744CrossRefGoogle Scholar
  4. 4.
    Rajagopal A, Yao K, Jen A K. Toward perovskite solar cell commercialization: a perspective and research roadmap based on interfacial engineering. Advanced Materials, 2018, 30(32): e1800455CrossRefGoogle Scholar
  5. 5.
    Jiang Y, Luo B, Jiang F, Jiang F, Fuentes-Hernandez C, Liu T, Mao L, Xiong S, Li Z, Wang T, Kippelen B, Zhou Y. Efficient colorful perovskite solar cells using a top polymer electrode simultaneously as spectrally selective antireflection coating. Nano Letters, 2016, 16 (12): 7829–7835CrossRefGoogle Scholar
  6. 6.
    Qin F, Tong J H, Ge R, Luo BW, Jiang F Y, Liu T F, Jiang Y Y, Xu Z Y, Mao L, Meng W, Xiong S X, Li Z F, Li L Q, Zhou Y H. Indium tin oxide (ITO)-free, top-illuminated, flexible perovskite solar cells. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2016, 4(36): 14017–14024CrossRefGoogle Scholar
  7. 7.
    Bai Y, Meng X, Yang S. Interface engineering for highly efficient and stable planar p-i-n perovskite solar cells. Advanced Energy Materials, 2018, 8(5): 1701883CrossRefGoogle Scholar
  8. 8.
    Luo D, Yang W, Wang Z, Sadhanala A, Hu Q, Su R, Shivanna R, Trindade G F, Watts J F, Xu Z, Liu T, Chen K, Ye F, Wu P, Zhao L, Wu J, Tu Y, Zhang Y, Yang X, Zhang W, Friend R H, Gong Q, Snaith H J, Zhu R. Enhanced photovoltage for inverted planar heterojunction perovskite solar cells. Science, 2018, 360(6396): 1442–1446CrossRefGoogle Scholar
  9. 9.
    Gu P Y, Wang N, Wang C Y, Zhou Y C, Long G K, TianMM, Chen W Q, Sun X W, Kanatzidis M G, Zhang Q C. Pushing up the efficiency of planar perovskite solar cells to 18.2% with organic small molecules as the electron transport layer. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2017, 5(16): 7339–7344CrossRefGoogle Scholar
  10. 10.
    Li M, Zhao C, Wang Z K, Zhang C C, Lee H K H, Pockett A, Barbé J, Tsoi W C, Yang Y G, Carnie M J, Gao X Y, Yang W X, Durrant J R, Liao L S, Jain S M. Interface modification by ionic liquid: a promising candidate for indoor light harvesting and stability improvement of planar perovskite solar cells. Advanced Energy Materials, 2018, 8(24): 1801509CrossRefGoogle Scholar
  11. 11.
    Mali S S, Hong C K. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides. Nanoscale, 2016, 8(20): 10528–10540CrossRefGoogle Scholar
  12. 12.
    Wang Z K, Liao L S. Doped charge-transporting layers in planar perovskite solar cells. Advanced Optical Materials, 2018, 6(17): 1800276CrossRefGoogle Scholar
  13. 13.
    Zhao T, Chueh C C, Chen Q, Rajagopal A, Jen A K Y. Defect passivation of organic–inorganic hybrid perovskites by diammonium iodide toward high-performance photovoltaic devices. ACS Energy Letters, 2016, 1(4): 757–763CrossRefGoogle Scholar
  14. 14.
    Liang P W, Chueh C C, Williams S T, Jen A K Y. Roles of fullerenebased interlayers in enhancing the performance of organometal perovskite thin-film solar cells. Advanced Energy Materials, 2015, 5 (10): 1402321CrossRefGoogle Scholar
  15. 15.
    Kuang C, Tang G, Jiu T, Yang H, Liu H, Li B, Luo W, Li X, Zhang W, Lu F, Fang J, Li Y. Highly efficient electron transport obtained by doping PCBM with graphdiyne in planar-heterojunction perovskite solar cells. Nano Letters, 2015, 15(4): 2756–2762CrossRefGoogle Scholar
  16. 16.
    Tang C G, Ang M C, Choo K K, Keerthi V, Tan J K, Syafiqah M N, Kugler T, Burroughes J H, Png R Q, Chua L L, Ho P K. Doped polymer semiconductors with ultrahigh and ultralow work functions for ohmic contacts. Nature, 2016, 539(7630): 536–540CrossRefGoogle Scholar
  17. 17.
    Chang C Y, Huang W K, Chang Y C, Lee K T, Chen C T. A solution-processed n-doped fullerene cathode interfacial layer for efficient and stable large-area perovskite solar cells. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2016, 4(2): 640–648CrossRefGoogle Scholar
  18. 18.
    Zhou H, Chen Q, Li G, Luo S, Song T B, Duan H S, Hong Z, You J, Liu Y, Yang Y. Interface engineering of highly efficient perovskite solar cells. Science, 2014, 345(6196): 542–546CrossRefGoogle Scholar
  19. 19.
    Yuan D X, Yuan X D, Xu Q Y, Xu M F, Shi X B, Wang Z K, Liao L S. A solution-processed bathocuproine cathode interfacial layer for high-performance bromine-iodine perovskite solar cells. Physical Chemistry Chemical Physics, 2015, 17(40): 26653–26658CrossRefGoogle Scholar
  20. 20.
    Lin Y, Shen L, Dai J, Deng Y, Wu Y, Bai Y, Zheng X, Wang J, Fang Y, Wei H, Ma W, Zeng X C, Zhan X, Huang J. p-conjugated lewis base: efficient trap-passivation and charge-extraction for hybrid perovskite solar cells. Advanced Materials, 2017, 29(7): 1604545CrossRefGoogle Scholar
  21. 21.
    Hu L, Liu T, Sun L, Xiong S, Qin F, Jiang X, Jiang Y, Zhou Y. Suppressing generation of iodine impurity via an amidine additive in perovskite solar cells. Chemical Communications, 2018, 54(37): 4704–4707CrossRefGoogle Scholar
  22. 22.
    Jiang Y Y, Li J, Xiong S X, Jiang F Y, Liu T F, Qin F, Hu L, Zhou Y H. Dual functions of interface passivation and n-doping using 2,6-dimethoxypyridine for enhanced reproducibility and performance of planar perovskite solar cells. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2017, 5(33): 17632–17639CrossRefGoogle Scholar
  23. 23.
    Ye Q Q, Wang Z K, Li M, Zhang C C, Hu K H, Liao L S. N-type doping of fullerenes for planar perovskite solar cells. ACS Energy Letters, 2018, 3(4): 875–882CrossRefGoogle Scholar
  24. 24.
    Li M, Wang Z K, Kang T, Yang Y, Gao X, Hsu C S, Li Y, Liao L S. Graphdiyne-modified cross-linkable fullerene as an efficient electron-transporting layer in organometal halide perovskite solar cells. Nano Energy, 2018, 43: 47–54CrossRefGoogle Scholar
  25. 25.
    Hu L, Liu T, Duan J, Ma X, Ge C, Jiang Y, Qin F, Xiong S, Jiang F, Hu B, Gao X, Yi Y, Zhou Y. An amidine-type n-dopant for solutionprocessed field-effect transistors and perovskite solar cells. Advanced Functional Materials, 2017, 27(41): 1703254CrossRefGoogle Scholar
  26. 26.
    Bin Z Y, Li J W, Wang L D, Duan L. Efficient n-type dopants with extremely low doping ratios for high performance inverted perovskite solar cells. Energy & Environmental Science, 2016, 9 (11): 3424–3428CrossRefGoogle Scholar
  27. 27.
    Wang Z, McMeekin D P, Sakai N, van Reenen S, Wojciechowski K, Patel J B, Johnston M B, Snaith H J. Efficient and air-stable mixedcation lead mixed-halide perovskite solar cells with n-doped organic electron extraction layers. Advanced Materials, 2017, 29(5): 1604186CrossRefGoogle Scholar
  28. 28.
    Beaula T J, Muthuraja P, Sethuram M, Dhandapani M, Rastogi V K, Jothy V B. Biological and spectral studies of O-tolyl biguanide: experimental and theoretical approach. Journal of Molecular Structure, 2017, 1128: 290–299CrossRefGoogle Scholar
  29. 29.
    Zhou Y, Fuentes-Hernandez C, Shim J, Meyer J, Giordano A J, Li H, Winget P, Papadopoulos T, Cheun H, Kim J, Fenoll M, Dindar A, Haske W, Najafabadi E, Khan T M, Sojoudi H, Barlow S, Graham S, Brédas J L, Marder S R, Kahn A, Kippelen B. A universal method to produce low-work function electrodes for organic electronics. Science, 2012, 336(6079): 327–332CrossRefGoogle Scholar
  30. 30.
    Jiang F Y, Liu T F, Luo B W, Tong J H, Qin F, Xiong S X, Li Z F, Zhou Y H. A two-terminal perovskite/perovskite tandem solar cell. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2016, 4(4): 1208–1213CrossRefGoogle Scholar
  31. 31.
    Liu T, Jiang F, Qin F, Meng W, Jiang Y, Xiong S, Tong J, Li Z, Liu Y, Zhou Y. Nonreduction-active hole-transporting layers enhancing open-circuit voltage and efficiency of planar perovskite solar cells. ACS Applied Materials & Interfaces, 2016, 8(49): 33899–33906CrossRefGoogle Scholar

Copyright information

© Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Ru Ge
    • 1
  • Fei Qin
    • 1
  • Lin Hu
    • 1
  • Sixing Xiong
    • 1
  • Yinhua Zhou
    • 1
    Email author
  1. 1.Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhanChina

Personalised recommendations