Fungus-based synthesis of chemically difficult-to-synthesize multifunctional nanoparticles of CUAIO₂

A fungus-based approach for the synthesis of transparent p-type conducting oxide, CuAlO₂, which is hard to synthesize chemically under technologically required low-temperature conditions, has been presented. To prepare CuAlO₂, controlling the valence state of Cu to 1+ in the reaction environment is crucial, as copper try to acquire the fully oxidized Cu²⁺ state as in CuO. It has been revealed that the fungus-based process enables the synthesis of this ternary compound at 50°C. This demonstrates the unique valence-controlled stoichiometric nanosynthesis capability of the biosynthesis process. The β-CuAlO₂ nanoparticles synthesized by the fungus based route were also found to be capped with natural protein making them water dispersible. These nanoparticles exhibited interesting multifunctionality that could be potentially useful in several applications.