Effect of non-stoichiometric solution chemistry on improving the performance of wide-bandgap perovskite solar cells

Mengjin Yang, Dong Hoe Kim, Yue Yu, Zhen Li, Obadiah G. Reid, Zhaoning Song, Dewei Zhao, Changlei Wang, Liwei Li, Yuan Meng, Ted Guo, Yanfa Yan, Kai Zhu

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

A high-efficiency wide-bandgap (WBG) perovskite solar cell is critical for developing perovskite-related (e.g., all-perovskite, perovskite/Si, or perovskite/Cu(In,Ga)Se2) tandem devices. Here, we demonstrate the use of non-stoichiometric precursor chemistry with excess methylammonium halides (MAX; X = I, Br, or Cl) for preparing high-quality ∼1.75-eV FA0.83Cs0.17Pb(I0.6Br0.4)3 perovskite solar cells. Among various methylammonium halides, using excess MABr in the non-stoichiometric precursor exhibits the strongest effect on improving perovskite crystallographic properties and device characteristics without affecting the perovskite composition. In contrast, using excess MAI significantly reduces the bandgap of perovskite due to the replacement of Br with I. Using 40% excess MABr, we demonstrate a single-junction WBG perovskite solar cell with stabilized efficiency of 16.4%. We further demonstrate a 20.3%-efficient 4-terminal tandem device by using a 14.7%-efficient semi-transparent WBG perovskite top cell and an 18.6%-efficient unfiltered (5.6%-efficient filtered) Si bottom cell.

Original languageEnglish
Pages (from-to)232-238
Number of pages7
JournalMaterials Today Energy
Volume7
DOIs
Publication statusPublished - 2018 Mar
Externally publishedYes

Keywords

  • Non-stoichiometric chemistry
  • Tandem solar cell
  • Wide bandgap perovskite

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

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