Morphology‐controlled Synthesis of Molybdenum Oxide with Tunable Plasmon Absorption for Phothermal Therapy of Cancer

Abstract Semiconductor nanocrystals showing surface plasmonic absorption features can be used as prospective substitutes for noble metallic nanoparticles. Herein, a creative one‐pot hydrothermal route without template is used to synthesize plasmonic oxygen deficiency molybdenum oxide (MoO 3‐x ) nanoparticles. The morphologies of as‐prepared MoO 3‐x nanomaterials arranged from amorphous to crystalline with the reaction temperature varied from 160 °C, 180 °C to 200 °C, namely MoO 3‐x quantum dots (QDs), MoO 3‐x nanosheets, and MoO 2 nanospheres. Simultaneously, in the near‐infrared region (NIR), MoO 3‐x nanomaterials exhibit gradually enhanced localized surface plasmon resonance (LSPR) absorption, of which MoO 2 nanospheres exhibit intense NIR absorption with a photothermal conversion efficiency up to 72.5% under 808 nm NIR laser irradiation. Moreover, the toxicity and cancer therapy efficacy of MoO 2 nanospheres have been systematically assessed in vitro and in vivo , respectively. The results revealed that MoO 2 nanospheres exhibit low toxicity and high therapeutic efficiency, making it an promising and effective photothermal agent in photothermal therapy