Jump to main content
Jump to site search


Halide Anion–Fullerene π Noncovalent Interactions: n-Doping and Halide Anion Migration Mechanism in p-i-n Perovskite Solar Cells

Abstract

Iodide–fullerene π interactions play decisive roles in n-doping and electron transport of fullerenes at perovskite–PCBM interface in the devices of perovskite solar cells (Pero-SCs). But instability issues of perovskite due to halide anion migration greatly limit Pero-SC’s practical application. To fully understand the properties of these interactions, we conducted systematic studies on fullerene ammonium halides containing I–, Br–, and Cl– that exist in perovskite. Our findings show that fullerene is an overwhelmingly strong electron acceptor that activates relatively inert halide anions (Br– and Cl–) and initiates n-doping process by forming anion–π interactions, which are closely related to the performance and stability of the p-i-n Pero-SC devices based on CH3NH3PbX3 (X = I, Br, and Cl) light absorber and fullerene (C60 or PCBM) electron transport layer (ETL). At the perovskite–fullerene interface in p-i-n Pero-SC, n-doping occurs by forming iodide–fullerene π interactions, which facilitates charge transport and improves the performance of devices by suppressing hysteresis. On the basis of experimental evidences and computational results, we propose a plausible mechanism for iodide migration attributed to its n-doping at interface and subsequent hopping of slideable iodide to a neighbouring fullerene given that space and energy are favorable. Thus, migration of halide anion through fullerene layer results in perovskite degradation and performance decay of the devices. This work highlights the importance of halide anion–fullerene π interactions in material chemistry and indicates that exploring halide anion blocking ETL in p-i-n Pero-SCs.

Back to tab navigation

Supplementary files

Publication details

The article was received on 19 Jul 2017, accepted on 06 Sep 2017 and first published on 06 Sep 2017


Article type: Paper
DOI: 10.1039/C7TA06335K
Citation: J. Mater. Chem. A, 2017, Accepted Manuscript
  •   Request permissions

    Halide Anion–Fullerene π Noncovalent Interactions: n-Doping and Halide Anion Migration Mechanism in p-i-n Perovskite Solar Cells

    X. Sun, L. Ji, W. Chen, X. Guo, H. WANG, M. Lei, Q. Wang and Y. Li, J. Mater. Chem. A, 2017, Accepted Manuscript , DOI: 10.1039/C7TA06335K

Search articles by author

Spotlight

Advertisements