Abstract
Hybrid organic-inorganic halide perovskites are promising materials for thin-film solar cells. However, the toxicity and instability of best-in-class lead-halide perovskite materials make them nonideal. To combat these issues, we replaced lead with bismuth and explored the sensitivity of these new lead-free materials to the valency and bonding of their cationic organic groups. Specifically, we synthesized and characterized the materials properties and photophysical properties of hexane-1,6-diammonium bismuth pentaiodide ((HDA2+)BiI5) and compared them to an analogue containing a more volatile organic group with half the number of carbon and nitrogen atoms in the form of n-propylammonium ((PA+)xBiI3+x, where 1 < x < 3). The full crystallographic structures of (HDA2+)BiI5 and (PA+)xBiI3+x were resolved by single-crystal X-ray diffraction. (HDA2+)BiI5 was shown to be pure-phase and have a one-dimensional structure, whereas (PA+)xBiI3+x was shown to be a mix of one-dimensional and zero-dimensional phases. Structures of the materials were confirmed by synchrotron X-ray diffraction of powders. Both (HDA2+)BiI5 and (PA+)xBiI3+x exhibit steady-state photoluminescence at room temperature. Density functional theory calculations of (HDA2+)BiI5 predict electronic absorption features and a ∼2 eV bandgap that are consistent with those observed experimentally. Structure-property relationships of the materials were examined, and moisture tolerance and film quality were found to be superior for dication-containing (HDA2+)BiI5 in relation to monocation-containing (PA+)xBiI3+x. We hypothesize that these trends are in part due to a molecular bridging effect enabled by the presence of the dicationic hexanediammonium groups in (HDA2+)BiI5. Solar cells fabricated using (HDA2+)BiI5 as the photoactive layer exhibited photovoltaic action while those containing (PA+)xBiI3+x did not, suggesting that organic dicationic groups are beneficial to light-absorber morphology and ultimately solar-cell performance.
Original language | English |
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Pages (from-to) | 1579-1587 |
Number of pages | 9 |
Journal | ACS Applied Energy Materials |
Volume | 2 |
Issue number | 3 |
DOIs | |
Publication status | Published - 25 Mar 2019 |
Bibliographical note
Funding Information:D.M.F. and S.A. acknowledge support from the Alfred P. Sloan Foundation under Grant FG-2017-8888 and the School of Physical Sciences at the University of California, Irvine. D.M F. acknowledges support by the DOE, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program under Contract DE SC0014664 and by the National Science Foundation Graduate Research Fellowship under Grant DGE-1321846. D.O.S. acknowledges support from the EPSRC (EP/N01572X/1) and membership of the Materials Design Network. A.M.G. acknowledges Diamond Light Source for the cosponsorship of a studentship on the EPSRC Centre for Doctoral Training in Molecular Modelling and Materials Science (EP/L015862/1). This work made use of the ARCHER UK National Supercomputing Service (http:// www.archer.ac.uk), via our membership in the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), and the UCL Legion and Grace HPC Facilities. M.C.B. acknowledges support as part of the Center for Hybrid Organic Inorganic Semiconductors for Energy, an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science within the U.S. Department of Energy. Work at the National Renewable Energy Laboratory (NREL) was performed under contract DE-AC36-08GO28308 from the U.S. Department of Energy to NREL. Synchrotron X-ray diffraction was performed on the 11-BM beamline at the Advanced Photon Source at Argonne National Laboratory by beamline staff. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. Scanning electron microscopy and X-ray diffraction measurements were performed at the UC Irvine Materials Research Institute. The authors thank Dr. Qiyin Lin (UC Irvine) for guidance in X-ray diffraction data analysis and Austin Ryan (UC Irvine) for assistance with single-crystal X-ray diffraction data acquisition and analysis.
Publisher Copyright:
© 2019 American Chemical Society.
Keywords
- bismuth halide
- dications
- hybrid organic-inorganic
- nontoxic
- photovoltaic
- solar cells
- solar fuels
- stability
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Electrochemistry
- Materials Chemistry
- Electrical and Electronic Engineering