A1 Refereed data article in a scientific journal
Perovskite‐Inspired Cs₂AgBi₂I₉: A Promising Photovoltaic Absorber for Diverse Indoor Environments
Authors: Mokurala, Krishnaiah; Singh, Kuntal; Monga, Sanchi; Tripathi, Akash; Karmakar, Sougata; Kumar, Ramesh; Tyrpenou, Christos; Volonakis, George; Manna, Debjit; Mäkinen, Paavo; Adarsh, K. V.; Bhattacharya, Saswata; Grandhi, G. Krishnamurthy; Rao, K. D. M.; Vivo, Paola
Publisher: Wiley
Publication year: 2025
Journal: Advanced Energy Materials
Article number: 2404547
Volume: 15
Issue: 7
ISSN: 1614-6832
eISSN: 1614-6840
DOI: https://doi.org/10.1002/aenm.202404547
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1002/aenm.202404547
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/522882883
Self-archived copy's licence: CC BY
Self-archived copy's version: Publisher`s PDF
Indoor photovoltaics (IPVs) using low-toxicity bismuth-based perovskite-inspired materials (PIMs) can potentially power the growing number of Internet of Things devices sustainably. However, modest indoor power conversion efficiency (PCE) values are reported due to intrinsic limitations of PIMs, particularly regarding charge carrier separation and transport. Herein, polycrystalline Cs₂AgBi₂I₉ thin films are developed with high phase purity and study their fundamental structural and photophysical properties. The comprehensive experimental and computational study reveals unique optoelectronic properties of Cs₂AgBi₂I₉ compared to other bismuth-containing PIMs, including weak electron-phonon coupling and low exciton binding energy (40 meV). This study also demonstrates the feasibility of large and highly mobile polaron formation in Cs₂AgBi₂I₉, supported by the observation of a phonon bottleneck and a delayed hot carrier lifetime of over 200 ps, which suggests enhanced defect tolerance and transport properties. Motivated by the suitable bandgap of this absorber (1.78 eV), the first Cs₂AgBi₂I₉-based IPVs are developed, achieving a PCE of ≈8% at 1000 lux. Notably, the devices maintain high performance across various indoor environments with white LED color temperatures ranging from 2700 to 6500 K. The calculated theoretical PCE limit of >40% and the promising operational stability position Cs₂AgBi₂I₉ as one of the most intriguing candidates for sustainable IPVs.
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Funding information in the publication:
M.K. and K.S. contributed equally to this work. P.V. and G.K.G. acknowledge the financial support of Jane and Aatos Erkko foundation within the SOL-TECH project. P.V. thanks Research Council of Finland, Decision No. 347772. M.K. and P.V. acknowledge the support of the SPOT-IT project founded by the CETPartnership, the Clean and Energy Transition Partnership under the 2022 CET Partnership joint call for research proposal, co-founded by the European Commission (GA 101069750) and with the founding of the organizations detailed on https://cetpartnership.eu/funding-agencies-and-call-modules. M.K. and P.V. thank the SPINIP- HORIZON-MSCA-2023-PF-1 (Project Grant No: 101150357) for funding. C.T. and G.V. acknowledge financial support by the Agence Nationale pour la Recherche through the CPJ program and the SURFIN project (Grant No. ANR-23-CE09-0001). P.M. thanks the financial support of the Finnish Cultural Foundation (grant 00240880, Kalle & Dagmar Välimaa fund). K. D. M. R. acknowledges the Science and Engineering Research Board (SERB, CRG/2022/0048730) and UGC-DAE CRS/2022- 23/01/676 projects for financial support and IACS for research facilities. K.S. acknowledges CSIR for fellowship. S.K. acknowledges UGC for fellowship. K.V.A. and A.T. gratefully acknowledge the support from the Department of Science and Technology (DST), India, through the project DST/NM/TUE/QM-8/2019(G)/1. The work is part of the Research Council of Finland Flagship Programme, Photonics Research and Innovation (PREIN), decision number 346511. This work made use of Tampere Microscopy Center facilities at Tampere University.S.M. acknowledges IIT Delhi for the senior research fellowship. S.B. acknowledges financial support from SERB under a core research grant [Grant No. CRG/2019/000647] to set up the High-Performance Computing facility “Veena” at IIT Delhi for computational resources.
