Unveiling Double A-Site Cation Perovskite-Inspired Materials: From 0D-Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> to 2D-Cs<sub>2</sub>AgBi<sub>2</sub>I<sub>9</sub> with Enhanced Charge Transport
Bismuth-based halideperovskite-inspired materials (PIMs) are gaining increasing attention as sustainable and stable alternatives to lead halide perovskites. However, many PIMs have wide band gaps (≥2 eV) and low electronic dimensionality, limiting their utility in optoelectronic applications. In this study, we introduce Cs2AgBi2I9, a two-dimensional perovskite-inspired absorber achieved through partial substitution of Cs+ with Ag+ at the A-site of Cs3Bi2I9. Single-crystal X-ray diffraction analysis reveals that silver atoms occupy the edge sites in the hexagonal lattice, resulting in contracted lattice parameters compared to the parent Cs3Bi2I9. The double A-cation substitution promotes orbital overlap between Ag 5s and I 6p orbitals, leading to a narrower band gap of 1.72 eV and a delocalized electronic structure in Cs2AgBi2I9. Consequently, the 2D-PIM exhibits a three-orders-of-magnitude lower electrical resistivity and an exceptional carrier mobility-lifetime product (μτ) of 3.4 × 10–3 cm2 V–1, representing the highest among solution-processed Bi-PIMs. Furthermore, low-temperature photoluminescence measurements indicate weak electron–phonon coupling, while transient absorption spectroscopy reveals extended hot-carrier lifetimes, suggesting efficient exciton transport in Cs2AgBi2I9. Utilizing these exceptional charge transport properties, Cs2AgBi2I9 photodetectors show a remarkable broad spectral response. This work demonstrates the potential of a double A-site cation engineering strategy to develop low-toxicity PIMs with precisely tailored structural and optoelectronic properties.
Authors
- K. D. M. Rao
- Md Sariful Sheikh (ORCID: https://orcid.org/0000-0002-0315-3825)
- Asha Singh (ORCID: https://orcid.org/0000-0002-8440-6256)
- S. Khan (ORCID: https://orcid.org/0000-0003-0447-7845)
- Manohar Chirumamilla (ORCID: https://orcid.org/0000-0002-6812-286X)
- Paola Vivo (ORCID: https://orcid.org/0000-0003-2872-6922)
- Praveen Kumar Velpula (ORCID: https://orcid.org/0000-0001-9897-6981)
- Mozakkar Hossain (ORCID: https://orcid.org/0000-0001-5074-2879)
- G. Krishnamurthy Grandhi (ORCID: https://orcid.org/0000-0001-9986-1000)
- Sandeep K. Reddy (ORCID: https://orcid.org/0000-0002-1458-6853)
- Ankita Narwal
- Sharma S. R. K. C. Yamijala (ORCID: https://orcid.org/0000-0003-1773-9226)
- Kiran Vankayala (ORCID: https://orcid.org/0000-0002-1910-696X)
- Kuntal Singh (ORCID: https://orcid.org/0009-0003-2864-0851)
- Saleem Khan
Institutions
- Raja Ramanna Centre for Advanced Technology (IN)
- Indian Institute of Technology Kharagpur (IN)
- Universität Hamburg (DE)
- Indian Association for the Cultivation of Science (IN)
- Tampere University (FI)
- Homi Bhabha National Institute (IN)
- Indian Institute of Technology Madras (IN)
- UGC DAE Consortium for Scientific Research (IN)
- Birla Institute of Technology and Science, Pilani (IN)
- Hamburg University of Technology (DE)
- Aalborg University (DK)
Publication Details
- Journal
- Chemistry of Materials
- Published
- 2024-08-09
- DOI
- https://doi.org/10.1021/acs.chemmater.4c01045
- Citations
- 3
- Primary Topic
- Perovskite Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.63
Funders
- Department of Science and Technology, Ministry of Science and Technology, India
- Council of Scientific and Industrial Research, India
- Academy of Finland
- Indian Institute of Technology Madras
- Ministry of Education, India
- Birla Institute of Technology and Science, Pilani
- Ministry of Electronics and Information technology
- Indian Institute of Technology Kharagpur
- Science and Engineering Research Board
- UGC-DAE Consortium for Scientific Research, University Grants Commission
- Northwest Fisheries Science Center