Development of inorganic-organic hybrid nanostructured material for H₂O₂ sensing application

An organic-inorganic hybrid nanoparticle (HNPs) composed of Sm(TTA)₃Phen, a coordination compound, and NaY_0.78Er_0.02Yb_0.20F_4, an upconversion nanoparticles (UCNPs), has been developed and used for H₂O₂ sensing application. Herein, Sm(TTA)₃Phen absorbs ultraviolet (UV) light and gives fluorescence in yellow-red-near infrared (NIR) region. Whereas, the UCNPs absorb NIR radiations (980 nm) and consequently emit in green-red region through photon upconversion process. Two important optical phenomena are observed when HNPs are simultaneously excited with UV (266 nm) and NIR (980 nm) laser radiation- (i) an energy transfer from Sm³⁺ to Er³⁺ ions, and (ii) color tunable emission from red to green, if the power of 980 nm laser is varied. Further, the material is highly competent to sense H₂O₂ through fluorescence quenching of Sm³⁺ emission in presence of H₂O₂. The nature of quenching is conspicuously different for different concentration/volume range of H₂O₂. For lower volume range, the rate of decrease of emission/excitation intensity is linear, while for higher volume range the decay in intensity is exponential. The attained minimum detection limit for H₂O₂ is 2 μl, which is significant for sensing applications. (paper)