Solvent-molecule-mediated manipulation of crystalline grains for efficient planar binary lead and tin triiodide perovskite solar cells

Leize Zhu, Brian Yuh, Stefan Schoen, Xinpei Li, Mohammed Aldighaithir, Beau J. Richardson, Ahmed Alamer, Qiuming Yu*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    61 Scopus citations


    Binary lead and tin perovskites offer the benefits of narrower band gaps for broader adsorption of solar spectrum and better charge transport for higher photocurrent density. Here, we report the growth of large, smooth crystalline grains of bianry lead and tin triiodide perovskite films via a two-step solution process with thermal plus solvent vapor-assisted thermal annealing. The crystalline SnxPb1-xI2 films formed in the first step served as the templates for the formation of crystalline CH3NH3SnxPb1-xI3 films during the second step interdiffusion of methylammonium iodide (MAI). Followed by dimethylsulfoxide (DMSO) vapor-assisted thermal annealing, small, faceted perovskite grains grew into large, smooth grains via the possible mechanism involving bond breaking and reforming mediated by DMSO solvent molecules. The absorption onset was extended to 950 and 1010 nm for the CH3NH3SnxPb1-xI3 perovskites with x = 0.1 and 0.25, respectively. The highest PCE of 10.25% was achieved from the planar perovskite solar cell with the CH3NH3Sn0.1Pb0.9I3 layer prepared via the thermal plus DMSO vapor-assisted thermal annealing. This research provides a way to control and manipulate film morphology, grain size, and especially the distribution of metal cations in binary metal perovskite layers, which opens an avenue to grow perovskite materials with desired properties to enhance device performance.

    Original languageEnglish (US)
    Pages (from-to)7621-7630
    Number of pages10
    Issue number14
    StatePublished - Apr 14 2016

    Bibliographical note

    Funding Information:
    The authors thank the financial support from the Defense Threat Reduction Agency (HDTRA1-15-1-0021). SEM images and XRD spectra were taken at the Nanotech User Facility, the UW site of the National Nanotechnology Infrastructure Network (NNIN) supported by the NSF. Device fabrication and performance measurements were carried out in the UW Photonics Research Facility. EQE measurements were conducted in the lab of Professor Lih Lin in the UW Department of Electrical Engineering.

    Publisher Copyright:
    © 2016 The Royal Society of Chemistry.

    ASJC Scopus subject areas

    • General Materials Science


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