Ion-Migration Inhibition by the Cation-π Interaction in Perovskite Materials for Efficient and Stable Perovskite Solar Cells

Dong Wei; Fusheng Ma; Rui Wang; Shangyi Dou; Peng Cui; Hao Huang; Jun Ji; Endong Jia; Xiaojie Jia; Sajid Sajid; Ahmed Mourtada Elseman; Lihua Chu; Yingfeng Li; Bing Jiang; Juan Qiao; Yongbo Yuan; Meicheng Li

doi:10.1002/adma.201707583

Ion-Migration Inhibition by the Cation-π Interaction in Perovskite Materials for Efficient and Stable Perovskite Solar Cells

Adv Mater. 2018 Aug;30(31):e1707583. doi: 10.1002/adma.201707583. Epub 2018 Jun 25.

Authors

Dong Wei¹, Fusheng Ma², Rui Wang², Shangyi Dou¹, Peng Cui¹, Hao Huang¹, Jun Ji¹, Endong Jia³, Xiaojie Jia³, Sajid Sajid¹, Ahmed Mourtada Elseman^{1

4}, Lihua Chu¹, Yingfeng Li¹, Bing Jiang¹, Juan Qiao², Yongbo Yuan⁵, Meicheng Li¹

Affiliations

¹ State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, Beijing, 102206, China.
² Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China.
³ Key Laboratory of Solar Thermal Energy and Photovoltaic System, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
⁴ Electronic and Magnetic Materials Department, Central Metallurgical Research and Development Institute (CMRDI), PO Box 87 Helwan, 1, Elfelezat Street, El-Tebbin, 11421, Cairo, Egypt.
⁵ Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Hunan, 410083, P. R. China.

PMID: 29938843
DOI: 10.1002/adma.201707583

Abstract

Migration of ions can lead to photoinduced phase separation, degradation, and current-voltage hysteresis in perovskite solar cells (PSCs), and has become a serious drawback for the organic-inorganic hybrid perovskite materials (OIPs). Here, the inhibition of ion migration is realized by the supramolecular cation-π interaction between aromatic rubrene and organic cations in OIPs. The energy of the cation-π interaction between rubrene and perovskite is found to be as strong as 1.5 eV, which is enough to immobilize the organic cations in OIPs; this will thus will lead to the obvious reduction of defects in perovskite films and outstanding stability in devices. By employing the cation-immobilized OIPs to fabricate perovskite solar cells (PSCs), a champion efficiency of 20.86% and certified efficiency of 20.80% with negligible hysteresis are acquired. In addition, the long-term stability of cation-immobilized PSCs is improved definitely (98% of the initial efficiency after 720 h operation), which is assigned to the inhibition of ionic diffusions in cation-immobilized OIPs. This cation-π interaction between cations and the supramolecular π system enhances the stability and the performance of PSCs efficiently and would be a potential universal approach to get the more stable perovskite devices.

Keywords: DFT calculations; cation-π interaction; efficient and stable perovskite solar cells; ion migration inhibition; perovskite materials.