An Oxa[5]helicene-Based Racemic Semiconducting Glassy Film for Photothermally Stable Perovskite Solar Cells

Niansheng Xu; Yang Li; Damiano Ricciarelli; Jianan Wang; Edoardo Mosconi; Yi Yuan; Filippo De Angelis; Shaik M Zakeeruddin; Michael Grätzel; Peng Wang

doi:10.1016/j.isci.2019.04.031

An Oxa[5]helicene-Based Racemic Semiconducting Glassy Film for Photothermally Stable Perovskite Solar Cells

iScience. 2019 May 31:15:234-242. doi: 10.1016/j.isci.2019.04.031. Epub 2019 Apr 26.

Authors

Affiliations

¹ Department of Chemistry, Zhejiang University, Hangzhou 310028, China.
² Department of Chemistry, Zhejiang University, Hangzhou 310028, China; Laboratory of Photonics and Interfaces, Institute of Chemical Sciences & Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
³ Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy; Computational Laboratory for Hybrid/Organic Photovoltaics, CNR-ISTM, Via Elce di Sotto 8, 06123 Perugia, Italy.
⁴ Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
⁵ Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy; Computational Laboratory for Hybrid/Organic Photovoltaics, CNR-ISTM, Via Elce di Sotto 8, 06123 Perugia, Italy; D3-Computation, Istituto Italiano di Tecnologia, Via Morego, Genova, Italy. Electronic address: filippo@thch.unipg.it.
⁶ Laboratory of Photonics and Interfaces, Institute of Chemical Sciences & Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
⁷ Department of Chemistry, Zhejiang University, Hangzhou 310028, China. Electronic address: pw2015@zju.edu.cn.

Abstract

Attaining the durability of high-efficiency perovskite solar cells (PSCs) operated under concomitant light and thermal stresses is still a serious concern before large-scale application. It is crucial to maintain the phase stability of the organic hole-transporting layer for thermostable PSCs across a range of temperatures sampled during device operation. To address this issue, we propose a racemic semiconducting glassy film with remarkable morphological stability, exemplified here by a low-molecular symmetry oxa[5]helicene-centered organic semiconductor (O5H-OMeDPA). The helical configuration of O5H-OMeDPA confers the trait of multiple-dimension charge transfer to the solid, resulting in high hole mobility of 6.7 × 10^-4 cm² V^-1 s^-1 of a solution-processed glassy film. O5H-OMeDPA is combined with a triple-cation dual-halide lead perovskite to fabricate PSCs with power conversion efficiencies of 21.03%, outperforming the control cells with spiro-OMeTAD (20.44%). Moreover, the cells using O5H-OMeDPA exhibit good long-term stability during full-sunlight soaking at 60°C.

Keywords: Chemistry; Energy Materials; Materials Science; Surface Science.