Scalable Spray Processing Resolves the Dimensionality–Transport Trade‐off in Lead‐Free Indoor Photovoltaics
ABSTRACT Scalable processing of lead‐free perovskite‐inspired absorbers is often constrained by a fundamental trade‐off: the structural reconstruction needed to improve electronic dimensionality can simultaneously introduce anisotropic textures that hinder vertical charge extraction. Here we show that this trade‐off can be overcome in vacancy‐ordered antimony halides by coupling ultrasonic spray deposition with solvent‐ and halide‐mediated crystallization control. Using Cs 3 Sb 2 I 9 –xCl x as a model system, we developed an ambient‐air deposition process followed by annealing under an N 2 /SbI 3 atmosphere route based on an amide‐free 2‐methoxyethanol/butanol solvent mixture that yields compact, pinhole‐free films without high‐boiling amide solvents. Chloride incorporation directs annealing‐induced reconstruction from a zero‐dimensional dimeric phase to a layered polymorph, while grazing‐incidence wide‐angle X‐ray scattering reveals that this transformation occurs without generating a strongly detrimental crystallographic texture. Transient absorption spectroscopy further shows suppressed self‐trapping and longer‐lived band‐edge carriers after dimensional reconstruction. As a result, the layered absorber retains an effective out‐of‐plane transport component and enables indoor photovoltaic (iPV) efficiencies up to 6.9% at 1000 lux (6500 K). Our results identify a general route by which scalable spray processing can be used not only to deposit lead‐free absorbers, but also to engineer phase evolution and transport‐relevant texture for efficient vertical optoelectronic operation.
Authors
- Mariangela Ruggeri (ORCID: https://orcid.org/0009-0006-7479-1222)
- Francesco Lamberti (ORCID: https://orcid.org/0000-0003-1720-8038)
- Simone Meloni (ORCID: https://orcid.org/0000-0002-3925-3799)
- Thomas Meredith Brown (ORCID: https://orcid.org/0000-0003-2141-3587)
- Ribhu Bhatia (ORCID: https://orcid.org/0009-0001-6870-0762)
- Abhisek Chakraborty (ORCID: https://orcid.org/0000-0001-8332-1229)
- Remah ElRashedy
- Teresa Gatti (ORCID: https://orcid.org/0000-0001-5343-8055)
- Rosaria Verduci (ORCID: https://orcid.org/0000-0001-8506-0114)
- Camilla Ferrante (ORCID: https://orcid.org/0000-0002-4869-449X)
- Giovanna D’Angelo (ORCID: https://orcid.org/0000-0002-3548-3255)
- Andrea Basagni (ORCID: https://orcid.org/0000-0001-9662-5125)
- Zhubing He (ORCID: https://orcid.org/0000-0002-2775-0894)
- Manas Ranjan Samantaray (ORCID: https://orcid.org/0000-0001-9429-0069)
- Marcello Righetto (ORCID: https://orcid.org/0000-0001-5507-1445)
- Sara Pescetelli (ORCID: https://orcid.org/0000-0002-3336-2425)
- Nicola Dengo (ORCID: https://orcid.org/0000-0003-2534-7265)
- Arpita Sarkar (ORCID: https://orcid.org/0000-0001-7375-8793)
- Antonio Agresti (ORCID: https://orcid.org/0000-0001-6581-0387)
- Zeynab Skafi (ORCID: https://orcid.org/0000-0002-3243-9021)
- Guilin Liu (ORCID: https://orcid.org/0000-0003-1158-7129)
- Jiacheng He (ORCID: https://orcid.org/0000-0002-1940-4262)
- Pietro Ostellari (ORCID: https://orcid.org/0009-0008-7428-3599)
- Carlo Scian
Institutions
- Jiangnan University (CN)
- University of Messina (IT)
- University of Padua (IT)
- Politecnico di Torino (IT)
- University of Ferrara (IT)
- Southern University of Science and Technology (CN)
Publication Details
- Journal
- Small Methods
- Published
- 2026-09-29
- DOI
- https://doi.org/10.1002/smtd.71072
- Primary Topic
- Perovskite Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00