J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (6): 987-993.DOI: 10.1016/j.jmst.2018.12.025

Previous Articles     Next Articles

Highly stable carbon-based perovskite solar cell with a record efficiency of over 18% via hole transport engineering

Qian-Qian Chua, Bin Dingab, Jun Pengb1, Heping Shenb, Xiaolei Lia, Yan Liua, Cheng-Xin Lia, Chang-Jiu Lia, Guan-Jun Yanga*(), Thomas P. Whiteb*(), Kylie R. Catchpoleb*()   

  1. a State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an, 710049, China
    b Research School of Engineering, The Australian National University, Canberra, ACT, 2601, Australia
  • Received:2018-11-25 Revised:2018-11-27 Accepted:2018-11-27 Online:2019-06-20 Published:2019-06-19
  • Contact: Yang Guan-Jun,P. White Thomas,R. Catchpole Kylie
  • About author:

    1 These authors contributed equally to this work.

Abstract:

Carbon-based perovskite solar cells show great potential owing to their low-cost production and superior stability in air, compared to their counterparts using metal contacts. The photovoltaic performance of carbon-based PSCs, however, has been progressing slowly in spite of an impressive efficiency when they were first reported. One of the major obstacles is that the hole transport materials developed for state-of-the-art Au-based PSCs are not suitable for carbon-based PSCs. Here, we develop a low-temperature, solution-processed Poly(3-hexylthiophene-2,5-diyl) (P3HT)/graphene composite hole transport layer (HTL), that is compatible with paintable carbon-electrodes to produce state-of-the-art perovskite devices. Space-charge-limited-current measurements reveal that the as-prepared P3HT/graphene composite exhibits outstanding charge mobility and thermal tolerance, with hole mobility increasing from 8.3 × 10-3 cm2 V-1 s-1 (as-deposited) to 1.2 × 10-2 cm2 V-1 s-1 (after annealing at 100 °C) - two orders of magnitude larger than pure P3HT. The improved charge transport and extraction provided by the composite HTL provides a significant efficiency improvement compared to cells with a pure P3HT HTL. As a result, we report carbon-based solar cells with a record efficiency of 17.8% (certified by Newport); and the first perovskite cells to be certified under the stabilized testing protocol. The outstanding device stability is demonstrated by only 3% drop after storage in ambient conditions (humidity: ca. 50%) for 1680 h (non-encapsulated), and retention of ca. 89% of their original output under continuous 1-Sun illumination at room-temperature for 600 h (encapsulated) in a nitrogen environment.

Key words: Planar carbon-based perovskite solar cells, Hole transport engineering, Recorded efficiency, Excellent moisture and light stability