Eu:Y2O3 highly dispersed fluorescent PVA film as turn off luminescent probe for enzyme free detection of H2O2

- 1. Importance and necessity: Many different approaches have been developed for detection of H2O2 till date including different electrochemical methods, spectrophotometry, chromatography as well as fluorescence. Recently fluorescent semiconductor or quantum dots (QDS) have attracted much attention due to their broad absorption with narrow emission with high brightness and good stability. However, the synthesis of QDS is little difficult with multiple step and need some specific equipment. Nowadays, rare earth ions doped luminescent materials are highlighted as fluorescent materials with high yield, which have been used in various field including solar cell, phosphor, color display etc.
- 2. Originality and novelty: In the present work, we have prepared a highly dispersed Eu:Y2O3 fluorescent flexible film of poly vinyl alcohol (EYCP film) for non-enzymatic detection of H2O2 by turn off probe for fluorescence using a solution combustion method.
- 3. Contribution and impact: The fluorescence spectra of EYCP has a number of emission sharp peak ranging from 560 nm to 700 nm corresponding to electrical dipole and magnetic dipole transition from excited 5D0→7Fj (j = 0, 1, 2, 3, 4) energy levels of doped Eu+3 ion in Y2O3 host. These excitation energy bands are attributed to charge transfer from the 2p orbital of oxygen to the 4f orbital of europium. The intense intensity peaks occurs at ∼611 nm corresponding to 5D0→7F2 transition. The EYCP film shows excellent fluorescence quenching in presence of H2O2 by significantly increasing concentration of H2O2 and completely quenched at ∼150 μM. This work gives insight for synthesis of rare earth metal doped oxide flexible film with great fluorescence properties and makes a room for further development of high quality of film for bio sensing with efficient performance. A linear relationship is observed between 0.0 and 60 μM with a correlation coefficient of 0.0989. This study is expected to have a significant impact on further study of the Eu:Y2O3 fluorescent flexible film for wide range application.
- We also believe that our work represents a methodological and scientific approach We are excited to share our manuscript with you and look forward to your positive response.

In this work, a novel sensing scaffold consisting highly dispersed Eu:Y2O3 fluorescent flexible film of poly vinyl alcohol (EYCP) was synthesized by simple mixing method and applied to facilitate non-enzymatic detection of hydrogen peroxide (H2O2) by turn off probe of fluorescence. The fluorescence spectra of EYCP consisting number of emission sharp transitions from excited, 5D0→7Fj (j = 0, 1, 2, 3, 4) energy levels of doped Eu3+ ion in Y2O3 host. In the presence of H2O2, the fluorescence intensity of the EYCP film was quenched due to the reduction of electron-hole pair recombination in Eu centers by electron transfer from Eu-O excited state to H2O2 energy level rather than 5D0 state of Eu3+, which reduces the number of electron in 5D0 state. The EYCP film shows excellent fluorescence quenching in presence of H2O2 by significantly increasing concentration of H2O2 and completely quenched at ∼150 μM. A linear relationship is observed between 0.0 and 60 μM with a correlation coefficient of 0.989. H2O2 sensing is also compared with the EYC nanoparticles. This study is expected to have a significant impact on further study of the Eu:Y2O3 fluorescent flexible film for wide range applications.