Research Center for Applied Science, Academia Sinica

Abstract Bi-layer molybdenum disulfide (MoS 2 ) films were prepared through sequential mono-layer MoS 2 growth using high temperature sulfurization of Mo oxide layers deposited by using the atomic layer deposition. An oxygen plasma treatment on the first MoS 2 layer will improve precursor distribution during the subsequent Mo oxide deposition, leading to a smoother second MoS 2 layer growth. Through the multi-stage sulfurization to enhance planar MoS 2 growth and depress Mo oxide segregation, uniform bi-layer MoS 2 films with improved crystallinity can be obtained. The bi-layer MoS 2 transistors exhibited a 42 times enhancement in field effect mobility compared with the mono-layer device. The sequential growth of mono-layer MoS 2 to achieve wafer-scale and bi-layer MoS 2 films provides a promising route for optimizing transistor performance toward practical applications.

Photocatalytic conversion of CO2 into value-added fuels offers a viable approach to combat climate change and address global energy demands. Here, we present a fluorine-doped SnS2 thin film with sulfur vacancy (i.e., SV-SnS2:F), prepared via thermal evaporation, post-sulfurization, and fluorine ion-implantation. Substitution of sulfur with fluorine and sulfur vacancy formation changes the product selectivity from CH4 to CO with about 40-fold enhanced yield and boosted internal quantum efficiency (IQE) of 0.52%. Transient absorption, in situ near-ambient pressure X-ray photoelectron, and in situ Fourier transform infrared spectroscopies, along with first-principles density functional theory calculations, suggest that nearest-neighbor Sn to F serves as an active site and stabilizes the *COOH intermediate. Our findings shed light on how F doping activates the nearby elements and its crucial role in intermediate stabilization toward selectivity change in a heterogeneous photocatalysis process.

Most noninvasive blood glucose technologies, especially wearable photoplethysmography devices, require multiple calibrations and are often limited to narrow cohorts such as unmedicated or mild cases. We assess whether a single pretest once per month can meet clinical accuracy while broadening applicability through cohort-specific models. We develop models for three groups: (i) individuals not using antidiabetic drugs, (ii) those using oral antidiabetic drugs only, and (iii) those using antidiabetic drugs in combination with other medications. Models are trained on cohort data with and without the monthly pretest and are then applied directly to personal testing without retraining. Inputs include dual-channel photoplethysmography signals and an inferred HbA1c (glycated hemoglobin) feature. Accuracy is summarized by mean absolute relative difference, clinical safety by the Parkes Error Grid, and improvements by a nonparametric rank-sum test. Here, we show that the best models using a single monthly pretest achieve mean absolute relative differences of 9.59, 12.23, and 16.40% for groups (i), (ii), and (iii), respectively. In the most complex group (iii), prediction errors are significantly lower than our earlier work according to the rank-sum test. The single-pretest models produce no clinically unacceptable readings on the Parkes Error Grid, likely due to dual-channel input and the inferred glycated-hemoglobin feature. A single monthly pretest enables accurate and clinically safe noninvasive glucose measurement across diverse patient groups. The approach operates without retraining or fine-tuning and can adapt to new users and devices through edge computing, supporting integration into current wearables for everyday diabetes management and public-health prevention.

Abstract By using graphene as the carrier transport layer and transition metal dichalcogenides (TMDs, WS 2 , MoS 2 , and WSe 2 ) as the light absorption layer, wavelength-tunable photodetectors can be fabricated on sapphire substrates. With the short carrier transport time in the graphene layer, the hole accumulation in the TMD layers would result in the conduction change in the graphene layer. Therefore, high responsivity values of 1521.9, 6077.9 and 3977.8 A/W at 630, 660 and 750 nm are observed for the WS 2 , MoS 2 and WSe 2 devices, respectively. With the high responsivity values, high detectivity values 6.9 (WS 2 ), 17.6 (MoS 2 ) and 9.2 (WSe 2 ) × 10 10 Jones are also observed for the three devices. Following the similar film transferring procedure and device fabrication procedure, photodetectors with mono-layer graphene on different mono-layer TMDs are fabricated on polyethylene terephthalate (PET) substrates. High responsivity values (10 2 -10 3 A/W) are still observed for the devices fabricated on flexible substrates. Although a relatively larger responsivity reduction is observed for the graphene/MoS 2 device under bending conditions, the similar responsivity values observed for the other two devices (graphene/WS 2 and graphene/WSe 2 ) still indicate that the thin-body nature of 2D materials is advantageous for the fabrication of flexible devices. With increasing WSe 2 layer numbers, even higher responsivities and significantly shortened rise/fall times 4.3/13.0 ms are observed for the mono-layer graphene/tri-layer WSe 2 photodetector, which has demonstrated that the excess electron storage in multi-layer 2D materials would result in fast hole accumulation/relaxation in the WSe 2 light absorption layer. The easy replacement of 2D materials with different bandgap values for wavelength-tunable detections also indicate an alternate application other than electronic devices of 2D materials in weak light detections.

Phage shock protein A (PspA), a recently identified member of the endosomal sorting complex required for transport III (ESCRT-III) superfamily, is proposed to be critical in stress-induced membrane remodeling in bacteria; however, the precise function and mechanism remain largely unexplored. In this study, we employed various lipid membrane models, including giant unilamellar vesicles, small unilamellar vesicles, and supported lipid bilayers, to study membrane-related activities of PspA. Through cell-free protein synthesis of PspA and biophysical characterizations, we demonstrated its capacity to self-assemble and uncovered the decisive role of the α1 region in facilitating this self-assembly. Notably, assays using lipid bilayer-based systems revealed a range of membrane-associated activities, including binding, disruption, and remodeling, encompassing membrane tubulation, elongation, and the formation of double-membrane vesicles. We discovered that the K55 residue within the α1 region is a key determinant for lipid binding and observed its effects on overall membrane remodeling activities, while the R44 residue is crucial for forming stable PspA rods. Together, these findings highlight the importance of the α1 domain in mediating membrane remodeling activity and suggest this may serve as a viable mechanism for other ESCRT-III proteins.

The advancement of polymer-based solid-state electrolytes (SPEs)is essential for the development of high energy density (ED) and long-operation durability lithium-metal batteries (LMBs). However, conventional poly (ethylene oxide) (PEO)-based electrolytes suffer from insufficient ionic conductivity (IC) at room temperature (RT) and limited capability to suppress lithium (Li) dendrite growth, particularly under high-rate operations. These challenges arise from unfavorable anion-solvate structures, which lead to a reduced Li-ion transference number (LITN) and hinder efficient ion transport. Here, a facile and scalable strategy is presented to design a self-healing composite polymer electrolyte by incorporating iminoboronate-functionalized networks. By succinonitrile (SN) into an anion-trapping polymer matrix, this approach enhances LITN while preserving overall IC. The resulting electrolyte facilitates rapid, selective, and uniform Li-ion transport, enabling stable LMB operation at 1 C for 480 cycles with an impressive 88% capacity retention. Moreover, the exceptional self-healing capacity of the iminoboronate-based polymer electrolyte (I-SHPE) significantly reinforces the mechanical properties of PEO-based electrolytes. The SN-embedded I-SHPE (I-SN-SHPE) exhibits a synergistic combination of high IC, anion-capture ability, and rapid self-healing properties. This work provides a promising strategy to overcome the intrinsic limitations of conventional PEO-based electrolytes, paving the way for safer and more durable LMBs.