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Self-Healing Beyond Molecular Iodine Locking in Formamidinium Lead Triiodide Perovskites

2026-02-28T15:00:00Z

Title: Self-Healing Beyond Molecular Iodine Locking in Formamidinium Lead Triiodide Perovskites Author(s): Zhao, Liangyu; Chi, Yi; Wu, Zijin; Park, Jaewang; Kim, Jongbeom; Qiang, Yue; Cao, Huaiman; Dai, Shouye; Chen, Yulong; Brocks, Geert; Sun, Licheng; Seok, Sang Il; Tao, Shuxia; Yu, Ze Abstract: Iodide-based perovskites commonly undergo irreversible decomposition under operational conditions due to molecular iodine (I2) generation, severely impacting device longevity. In this study, we introduce 1,4-dithiane (DT) as an efficient molecular iodine locking (MIL) agent at grain boundaries and surfaces of formamidinium lead triiodide (FAPbI3) perovskite absorbers. The incorporation of DT not only minimizes iodine evaporation through robust S & centerdot;& centerdot;& centerdot;I halogen bonding but also facilitates the dissociation of I-I bonds, enabling dynamic self-healing of the delta-phase into the photoactive alpha-phase of FAPbI3 at room temperature. This "self-healing beyond MIL" mechanism ensures exceptional device stability under continuous light soaking (ISOS-L-1I), light-dark cycling (ISOS-LC-1I), and damp-heat stress (ISOS-D-3), with PSCs retaining >95% of their initial performance for 1000 h. The established iodine cycling process-comprising iodine capture, iodide regeneration, and vacancy backfilling-substantially enhances perovskite durability. Overall, this strategy presents a promising pathway for advancing robust PSCs and other iodine-sensitive optoelectronic devices.

Ion channel-gated covalent organic framework membrane for sustainable lithium-sulfur batteries

2025-06-30T15:00:00Z

Title: Ion channel-gated covalent organic framework membrane for sustainable lithium-sulfur batteries Author(s): Li, Zhongping; Kim, Jae-seung; Moon, Hyunseok; Oh, Kyeongseok; Hou, Yuxin; Park, Sodam; Ryu, Kun; Li, Changqing; Seo, Jeongmin; Liu, Xiaoming; Baek, Jong-Beom; Seo, Dong-Hwa; Lee, Sang-young Abstract: Lithium-sulfur (Li-S) batteries hold promise as a compelling alternative to current state-of-the-art Li-ion batteries due to their high theoretical capacity, low cost and the natural abundance of sulfur. However, the practical realization of Li-S batteries has been plagued by the longstanding trade-off issue between polysulfide shuttle suppression and Li+ transport. Here, we report an ion channel-gated covalent organic framework (COF) as an ionic diode membrane strategy to address this conflicting requirement. By tuning the chemical structure of tethered anions, the resulting COF features 1D anionic channels with optimized charge delocalization and pore size. The bulky anions enhance Li+ dissociation and conduction while effectively repelling polysulfides dissolved from S cathodes. Additionally, the COF ionic diode mitigates self-discharge and inhibits parasitic reactions. Consequently, Li-S cells assembled with the COF ionic diode improve charge/discharge capacities and cycle life under constrained operating conditions. © 2025 The Author(s).

A DFT investigation on bi-functional {1 2 1} faceted orthorhombic β−Sb2O3 for water splitting application

2025-06-30T15:00:00Z

Title: A DFT investigation on bi-functional {1 2 1} faceted orthorhombic β−Sb2O3 for water splitting application Author(s): Barve, Harshada A.; Deshmukh, Rupali R.; Shaikh, Zeenat A.; Ghule, Balaji G.; Shaikh, Shoyebmohamad F.; Jang, Ji-Hyun; Mane, Rajaram S.; Gunturu, Krishna Chaitanya Abstract: An investigation into the bi-functional nature of the {1 2 1} plane of β-Sb2O3 during water splitting reactions is conducted using density functional theory calculations, examining oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The facet's asymmetric geometry and distorted electronic density create active sites that facilitate efficient adsorption of H2O and reaction intermediates during catalytic reaction kinetics. The band structure and density of states (DOS) analysis using the HSE06 functional confirms the presence of lone pairs at metal ions near the valence band maximum, inducing an asymmetric charge distribution across the surface. The OER and HER mechanisms on {1 2 1} faceted orthorhombic β−Sb2O3 are further elucidated using binding energies, adsorption energies, and overpotential details at GGA-PBE as well as GGA-PBE-D3 level of theory. The identification of distinct active sites for OER and HER, further the moderate and excellent calculated lower overpotentials of 1.08 V and 0.11 V for OER and HER processes respectively, underscores the potential of {1 2 1} faceted orthorhombic β-Sb2O3 as a bifunctional electrocatalyst in the technology used for overall water splitting. © 2025 The Authors

Robust biodegradable synapse with sub-biological energy and extended memory for intelligent reflexive system

2025-10-31T15:00:00Z

Title: Robust biodegradable synapse with sub-biological energy and extended memory for intelligent reflexive system Author(s): Chang, Yoojin; Na, Sangyun; Ro, Yun Goo; Park, Cheolhong; Jung, Seokhee; Park, Yong-Jin; Kwak, Min Sub; Kim, Jeeyoon; Oh, Hyeji; Kim, Jaejun; Ko, Hyunhyub Abstract: Biodegradable artificial synapses hold great promise for sustainable neuromorphic electronics, yet combining long-term memory, ultralow energy consumption, and mechanical robustness remains challenging. Here, we report a fully biodegradable multilayer artificial synapse (M-AS) composed of crosslinked chitosan-guar gum (CS-GG) ion-active layers (IALs) and a cellulose acetate (CA) ion-binding layer (IBL). This trilayer architecture enhances ion trapping via ion-dipole coupling (IDC) at the IAL-IBL interface, while hydrogen-bonded crosslinking within the CS-GG matrix enhances mechanical and environmental stability. Sodium chloride, embedded in the IALs, serves as a mobile ionic species analogous to biological neurotransmitters, enabling low-voltage ion migration. Upon electrical stimulation, ion migration and dipole alignment induce IDC, leading to partial ion retention and cascade-like postsynaptic current responses that support memory formation. The M-AS supports key synaptic functionalities-including paired-pulse facilitation, short-term and long-term plasticity, multilevel memory encoding, and bidirectional modulation-under sub-millivolt operation. It achieves the longest long-term memory time (5944 s) reported among biodegradable artificial synapses and an energy consumption (0.85 fJ/event) lower than that of biological synapses. Integration with a thermistor and robotic actuator enables a bioinspired reflexive system capable of adaptive, stimulus-dependent learning and reflex-like behaviors. These results demonstrate the potential of M-AS for low-power, intelligent human-machine interfaces.