Quasi-2D Hybrid Perovskite Formation Using Benzothieno[3,2-b]Benzothiophene (BTBT) Ammonium Cations

Substantial Cesium Lead(II) Iodide Black Phase Stabilization

Journal article (2022)

Authors

Paul Henry Denis Associated lab IMOMEC, University of Hasselt
Martijn Mertens Associated lab IMOMEC, University of Hasselt
Wouter T.M. Van Gompel Associated lab IMOMEC, University of Hasselt
Arthur Maufort University of Hasselt, Associated lab IMOMEC
Sigurd Mertens University of Hasselt, Associated lab IMOMEC
Z. Wei ChemE/Opto-electronic Materials - AS
Melissa Van Landeghem University of Hasselt, Associated lab IMOMEC
Sam Gielen University of Hasselt, Associated lab IMOMEC
F.C. Grozema ChemE/Opto-electronic Materials - AS
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Research Group
ChemE/Opto-electronic Materials (AS) (TU Delft)
Copyright: © 2022 Paul Henry Denis, Martijn Mertens, Wouter T.M. Van Gompel, Arthur Maufort, Sigurd Mertens, Z. Wei, Melissa Van Landeghem, Sam Gielen, F.C. Grozema, More Authors
DOI
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https://doi.org/10.1002/adom.202200788
Thermal stability Photodetectors Cesium black phase stabilization Low-dimensional perovskites Moisture stability
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Published Date

2022

Language

English

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Faculty

Applied Sciences

Department

ChemE/Chemical Engineering

Research Group

ChemE/Opto-electronic Materials

Abstract

3D hybrid perovskites (APbX3) have made a significant impact on the field of optoelectronic materials due to their excellent performance combined with facile solution deposition and up-scalable device fabrication. Nonetheless, these materials suffer from environmental instability. To increase material stability, the organic cation (A) is substituted by the non-volatile cesium cation. However, the desired photoactive cesium lead(II) iodide black phase is metastable in ambient conditions and spontaneously converts into the photo-inactive yellow δ-phase. In this work, the black phase is stabilized by the formation of a quasi-2D perovskite containing a benzothieno[3,2-b]benzothiophene (BTBT) large organic ammonium cation. Thermal analysis shows that degradation of the butylammonium (BA)-based quasi-2D perovskite (BA)2CsPb2I7 sets in at ≈130 °C, while (BTBT)2CsPb2I7 is phase-stable until ≈230 °C. Additionally, the (BTBT)2CsPb2I7 film does not show any sign of degradation after exposure to 77% Relative Humidity in the dark for 152 days, while (BA)2CsPb2I7 degrades in a single day. Photoconductor-type detectors based on (BTBT)2CsPb2I7 demonstrate an increased external quantum efficiency and a similar specific detectivity compared to the BA-based reference detectors. The results demonstrate the utility of employing a BTBT cation within the organic layer of quasi-2D perovskites to significantly enhance the stability while maintaining the optoelectronic performance.