Aqueous-Isopropanol-Based Green Ink Formulation of Single-Crystalline Transition Metal Chalcogenides for Fully-Printed Strain-Insensitive Flexible Sensing Electronics

• • Green ink formulation using zwitterionic CAB enables liquid-phase exfoliation of single-crystalline TMDs in water/IPA, achieving stable dispersions (>1 month) and concentrations up to 2 mg/mL without additives or binders, eliminating toxic solvents for scalable manufacturing. • • Fully-printed MoSe2/CAB humidity sensors show superior sensitivity (ΔI/I0 = 468.1) and rapid response/recovery times (27 s/0.42 s) under bending, outperforming conventional sensors for wearable applications. • • Inkjet-printed WTe2/CAB pads on 6-μm-thick substrates exhibit resistance variation of only 1.4% under single bending (radius 69.6 to 6.6 mm) and 2% after 1,000 cyclic bends, demonstrating strain insensitivity critical for reliable biopotential monitoring. • • WTe2 pads acquire high-quality ECG signals with clear P wave, QRS complex, and T wave, and stable EMG signals during muscle contraction/relaxation, validating their clinical utility in wearable diagnostics.