Tuning of defect-mediated AgInS2-based chalcogenides for highly efficient electroactive energy storage electrodes
- 1Department of Physics, COMSATS University Islamabad Lahore Campus 54000 Pakistan
- 2State Key Laboratory of Advanced Papermaking & Paper-based Materials, South China University of Technology Guangzhou 510640 China
Abstract
Metal chalcogenides with enhanced electrochemical and electrical properties are promising next-generation supercapacitor electrodes. Cu-, Mn-, and Cu–Mn-doped and pristine AgInS2 nanoparticles have been synthesized through a simple and low-cost hydrothermal route. Herein, we demonstrate for the first time a direct correlation between dual-dopant synergy and the defect landscape and charge-transfer pathways of an AgInS2 lattice (I–III–VI2) that tolerates cation substitution without structural degradation. The structural analysis shows that both pristine and doped samples form a mixed orthorhombic/tetragonal AgInS2 framework with orthorhombic phase dominance, whereas doping reduces the crystallite size from ∼25 nm to ∼14, ∼9, and ∼18 nm for Cu-, Mn-, and Cu–Mn-doped samples, consistent with the SEM particle-size reduction from 40–55 nm in pristine AgInS2. Raman and X-ray photoelectron spectroscopy (XPS) verify the Ag–S and S–S vibrational modes and the Ag+, In3+ and S2− chemical states of the host lattice, with Cu and Mn incorporated as Cu+ and Mn2+. UV-vis and photoluminescence (PL) spectroscopy indicate that doping modifies the electronic structure and defect landscape: the optical band gap varies from 3.52 eV to 3.50, 3.55 and 3.40 eV for the Cu-, Mn- and Cu–Mn-doped samples, while broad defect-related emission over 500–900 nm confirms intrinsic and dopant-induced defect states opening multiple charge-transfer pathways. The specific capacitance increases from 72.3 to 96.7, 129.8 and 189.27 F g−1 for the pristine and Cu-, Mn- and Cu–Mn-doped electrodes at 5 mV s−1, the capacitive contribution increases from 0.41% to 10.41%, 13.54% and 19.85%, and the charge-transfer resistance decreases from 1.652 Ω to 1.3, 1.22, and 0.693 Ω, with b-values of 0.5–0.69 indicating a hybrid diffusion and capacitive-controlled charge-storage mechanism. The improved performance of the co-doped electrode is ascribed to the synergistic effect of Cu and Mn, which enhances the accessibility of electroactive sites, interfacial charge transfer, and ion transportation, indicating that Cu–Mn co-doping is a promising strategy for defect and composition engineering of high-performance AgInS2-based supercapacitor electrodes.
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BibTeX
@article{mustafa2026tuning,
title = {{Tuning of defect-mediated AgInS2-based chalcogenides for highly efficient electroactive energy storage electrodes}},
author = {Faiza Mustafa and Aneeqa Masood and Waris Ali and Ume Zainab and Ayesha Iram and Sameen Ilyas and Zhouyang Xiang and Ishrat Sultana and Aamir Razaq},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra09800b},
url = {https://europepmc.org/article/PMC/PMC13690256},
note = {CC BY},
}
RIS
TY - JOUR
TI - Tuning of defect-mediated AgInS2-based chalcogenides for highly efficient electroactive energy storage electrodes
AU - Faiza Mustafa
AU - Aneeqa Masood
AU - Waris Ali
AU - Ume Zainab
AU - Ayesha Iram
AU - Sameen Ilyas
AU - Zhouyang Xiang
AU - Ishrat Sultana
AU - Aamir Razaq
PY - 2026
DA - 2026/10/22
JO - RSC advances
DO - 10.1039/d6ra09800b
UR - https://europepmc.org/article/PMC/PMC13690256
AB - Metal chalcogenides with enhanced electrochemical and electrical properties are promising next-generation supercapacitor electrodes. Cu-, Mn-, and Cu–Mn-doped and pristine AgInS2 nanoparticles have been synthesized through a simple and low-cost hydrothermal route. Herein, we demonstrate for the first time a direct correlation between dual-dopant synergy and the defect landscape and charge-transfer pathways of an AgInS2 lattice (I–III–VI2) that tolerates cation substitution without structural degradation. The structural analysis shows that both pristine and doped samples form a mixed orthorhombic/tetragonal AgInS2 framework with orthorhombic phase dominance, whereas doping reduces the crystallite size from ∼25 nm to ∼14, ∼9, and ∼18 nm for Cu-, Mn-, and Cu–Mn-doped samples, consistent with the SEM particle-size reduction from 40–55 nm in pristine AgInS2. Raman and X-ray photoelectron spectroscopy (XPS) verify the Ag–S and S–S vibrational modes and the Ag+, In3+ and S2− chemical states of the host lattice, with Cu and Mn incorporated as Cu+ and Mn2+. UV-vis and photoluminescence (PL) spectroscopy indicate that doping modifies the electronic structure and defect landscape: the optical band gap varies from 3.52 eV to 3.50, 3.55 and 3.40 eV for the Cu-, Mn- and Cu–Mn-doped samples, while broad defect-related emission over 500–900 nm confirms intrinsic and dopant-induced defect states opening multiple charge-transfer pathways. The specific capacitance increases from 72.3 to 96.7, 129.8 and 189.27 F g−1 for the pristine and Cu-, Mn- and Cu–Mn-doped electrodes at 5 mV s−1, the capacitive contribution increases from 0.41% to 10.41%, 13.54% and 19.85%, and the charge-transfer resistance decreases from 1.652 Ω to 1.3, 1.22, and 0.693 Ω, with b-values of 0.5–0.69 indicating a hybrid diffusion and capacitive-controlled charge-storage mechanism. The improved performance of the co-doped electrode is ascribed to the synergistic effect of Cu and Mn, which enhances the accessibility of electroactive sites, interfacial charge transfer, and ion transportation, indicating that Cu–Mn co-doping is a promising strategy for defect and composition engineering of high-performance AgInS2-based supercapacitor electrodes.
SN - 2046-2069
ER -