Additive‐Free Oxidized Spiro‐MeOTAD Hole Transport Layer Significantly Improves Thermal Solar Cell Stability
Name
Advanced Energy Materials - 2024 - Grotevent - Additive‐Free Oxidized Spiro‐MeOTAD Hole Transport Layer Significantly.pdf
Description
Published version
Size
3.42 MB
Format
Adobe PDF
Checksum (MD5)
19ca28807a736b6d21b821a8761e7051
Author(s)
Grotevent, Matthias J
Lu, Yongli
Šverko, Tara
Shih, Meng‐Chen
Tan, Shaun
Zhu, Hua
Dang, Tong
Mwaura, Jeremiah K
Swartwout, Richard
Beiglböck, Finn
Date Issued
June 6, 2024
Journal
Advanced Energy Materials
Publisher
Wiley
Citation
Grotevent, Matthias J, Lu, Yongli, Šverko, Tara, Shih, Meng‐Chen, Tan, Shaun et al. 2024. "Additive‐Free Oxidized Spiro‐MeOTAD Hole Transport Layer Significantly Improves Thermal Solar Cell Stability." Advanced Energy Materials, 14 (31).
Version
Final published version
Abstract
Perovskite solar cells are among the most promising new solar technologies, already surpassing polycrystalline silicon solar cell efficiencies. The stability of the highest efficiency devices at elevated temperature is, however, poor. These cells typically use Spiro‐MeOTAD as the hole transporting layer. It is generally believed that additives, required for enhancing electrical conductivity and optimizing energy level alignment, are responsible for the reduced stability—inferring that Spiro‐MeOTAD based hole transporting layers are intrinsically unstable. Here, a reliable noble metal free synthesis of Spiro‐MeOTAD (bis(trifluoromethane)sulfonimide)4 is presented which is used as the oxidizing agent. No additives are added to the partially oxidized Spiro‐MeOTAD hole‐transporting layer. Device efficiencies up to 24.2% are achieved. Electrical conductivity is largely developed by the first 1% oxidation. Further oxidation shifts the energy levels away from the vacuum level, which allows tuning of the energy level alignment without the use of additives—contradicting the current understanding of this system. Without additives, devices demonstrate significant improvement in stability at elevated temperatures up to 85 °C under one sun over 1400 h continuous illumination. The remaining degradation is pinpointed to ion migration and reactions in the perovskite layer which may be further suppressed with compositional engineering and adequate ion barrier layers.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Research Laboratory of Electronics
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivatives
Persistent DSpace Link
DOI of Published Version
10.1002/aenm.202400456
