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Vol. 18 (2026)

Ambient Confined-Space Annealing for Crystallization Enhancement and Defect Passivation in Sb2S3 Thin-Film Solar Cells

https://doi.org/10.1007/s40820-026-02193-w
Li‑Mei Lin
College of Physics and Energy, Fujian Normal University, Fuzhou 350117, People’s Republic of China
Jie Huang
College of Physics and Energy, Fujian Normal University, Fuzhou 350117, People’s Republic of China
Hu Li
College of Physics and Energy, Fujian Normal University, Fuzhou 350117, People’s Republic of China
Jin‑Rui Cai
Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage, Fujian Normal University, Fuzhou 350117, People’s Republic of China
Shui‑Yuan Chen
Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage, Fujian Normal University, Fuzhou 350117, People’s Republic of China
Jian‑Min Li
Key Laboratory of Artificial Micro and Nano‑Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People’s Republic of China
Xiao‑Min Wang
Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, People’s Republic of China
Gui‑Lin Chen
College of Physics and Energy, Fujian Normal University, Fuzhou 350117, People’s Republic of China

Corresponding Author: Gui‑Lin Chen

glchen@fjnu.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 359

Abstract

Annealing is a crucial step for recrystallizing Sb2S3 and forming high-quality Sb4S6 chain-like crystals, which is essential for achieving high-efficiency photovoltaic devices. However, this process currently faces a fundamental trade-off: Although high-temperature annealing enhances crystallinity, it also introduces severe sulfur and Sb2S3 molecular escape, ultimately degrading device performance. To overcome this limitation, we propose a confined-space annealing (CSA) strategy that operates via a dual mechanism. Physical confinement generates a high local vapor pressure, which suppresses Sb2S3 re-volatilization and enables recrystallization into large-grain films under atmospheric pressure. Controlled oxygen doping preferentially fills sulfur vacancy sites, suppresses interstitial Sbi defects, and promotes the self-assembly of Sb2O3 nano-belts at grain boundaries, effectively blocking leakage paths. As a result, the CSA films exhibit a 60.9% reduction in VS defects and a 40.3% improvement in carrier collection efficiency compared to pristine films. Carbon-based devices fabricated using this approach achieve a power conversion efficiency of 7.17% (VOC = 750 mV, JSC = 14.26 mA cm−2, FF = 62.7%), which is the highest reported value for Sb2S3 solar cells fabricated entirely in ambient atmosphere. This work not only offers a practical fabrication route under ambient conditions but also provides fundamental insights into defect passivation in chalcogenide photovoltaics.


Highlights:
1 Effectively inhibits the re-volatilization of Sb2S3, allowing recrystallization at 450 °C, and preparing films with large grains.
2 The confined-space annealing strategy enables controlled dynamic in situ oxidation targeting defect sites and reduces the defect concentration of the VS by 60.9%.
3 It represents the first reported highest efficiency of 7.17% in full air, which is 40.3% higher than the efficiency of Sb2S3 devices under the N2 atmosphere.

Keywords

Sb2S3 Confined-space annealing Crystal growth Passivation Sb2O3
Lin, Li‑Mei, Jie Huang, Hu Li, Jin‑Rui Cai, Shui‑Yuan Chen, Jian‑Min Li, Xiao‑Min Wang, and Gui‑Lin Chen. 2026. “Ambient Confined-Space Annealing for Crystallization Enhancement and Defect Passivation in Sb2S3 Thin-Film Solar Cells”. Nano-Micro Letters 18 (May):359. https://doi.org/10.1007/s40820-026-02193-w.
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