Reducing carrier transport barrier in anode interface enables efficient and stable inverted mesoscopic methylammonium-free perovskite solar cells

Yu Chen, Weijian Tang, Yihui Wu*, Xin Yu, Jianchao Yang, Qingshan Ma, Shubo Wang, Jun Jiang, Shengli Zhang, Wen Hua Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Exploitation of novel inorganic hole-transport materials (HTM) is one of the most promising approaches that achieve stable and efficient perovskite solar cells (PSCs). However, the low conductivity and large carrier transport barriers of the commonly used HTMs/perovskite system severely limit the device performance. Herein, Mg2+ doped CuCrO2 (M:CCO) nanocrystals are synthesized using a hydrothermal method and further adopted as the HTM for inverted PSCs. The hole conductivity of CuCrO2 is substantially enhanced upon ion doping. To address the anode/perovskite interfacial contact issues, the resultant M:CCO is designed to be a mesoporous structure atop an ultrathin compact NiOx film (5 nm). This mesoscopic structured bilayer hole-transport layers (HTLs) with well-matched graded energy levels effectively shorten the charge transport pathway, reduce carrier transport barrier in HTL/perovskite interface, and improve the light harvesting efficiency. Combined with the design of a top electron-transport layer and the usage of methylammonium (MA)-free perovskites, a champion PCE of 21.64% has been achieved, which is among the highest efficiencies for inverted MA-free, cesium/formamidinium-based PSCs to date. Moreover, the unsealed device shows excellent long-term stability: more than 91% and 80% of their initial efficiencies were retained after light soaking under 1 sun illumination for 400 h and thermal aging at 85 °C for 1000 h, respectively. This study provides a potential strategy for developing highly efficient and stable inverted PSCs.

Original languageEnglish
Article number131499
JournalChemical Engineering Journal
Volume425
DOIs
Publication statusPublished - 1 Dec 2021
Externally publishedYes

Keywords

  • Carrier transport dynamics
  • Inorganic hole-transport materials
  • Inverted perovskite solar cells
  • Mesoporous structure
  • Methylammonium-free

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