Laser-induced biocompatible molybdenum dioxide for versatile wearable bioelectronics

Molybdenum dioxide (MoO₂), a transition metal oxide known for its exceptional electrical conductivity, photothermal sensitivity, and biocompatibility, is traditionally synthesized via hydrothermal methods that suffer from long reaction cycles, harsh environments, and limited patternability. Herein, an ambient-condition, in-situ laser-induced photothermal reduction of MoO₃ to MoO₂ is realized by exploiting a tailored precursor ink and localized laser irradiation. The intense photothermal heat facilitates the reduction of MoO₃ by the reductant, synchronously driving the structural phase transition and compact sintering. The resulting MoO₂ exhibits outstanding electrical conductivity (up to 1.42 × 10⁵ S/m) while maintaining competitive biocompatibility. As typical demonstrations, the laser-induced MoO₂ is seamlessly integrated into wearable bioelectronics for multifunctional applications, ranging from electro-/photo-thermal therapy to wireless electrophysiological signal monitoring (e.g., surface electromyography and electrocardiogram). This work affords a scalable, energy-efficient route for manufacturing high-performance transition metal oxide-based flexible electronics.