Optical, magnetic and electrical properties of multifunctional Cr3+: Polyethylene oxide (PEO) + polyvinylpyrrolidone (PVP) polymer composites

• Semi-crystalline nature was observed and complex formation analysis was elucidated.
• Strong red emission was observed from Cr3+: PEO + PVP polymers.
• Super paramagnetic nature was evaluated from the EPR and VSM analysis.
• Cr3+(0.1 wt%): polymer reveals high ionic conductivity as 1.14 × 10−5 S/cm at 373 K.
• Cr3+:PEO + PVP polymer composites were identified as multifunctional polymers.

Multifunctional polymer composite films of PEO + PVP and also doped with Cr3+ ions in different concentrations have been synthesized by a solution casting method. The semi-crystalline nature of the polymer films was confirmed by XRD studies. Raman spectral analysis confirms the complex formation of the polymer with dopant ions. The optical absorption spectrum of Cr3+ doped polymer exhibits three absorption bands pertaining to Cr3+ ions in octahedral symmetry. From the absorption spectrum, Racah parameters were evaluated. The red emission at 614 nm (4T2g→4A2g) has been observed for the Cr3+: PEO + PVP polymer under the UV excitation. EPR spectra of Cr3+ ions doped polymers at different concentrations of Cr3+ ions exhibit resonance signals which are characteristic of Cr3+ ions in the octahedral symmetry. Cr3+: PEO + PVP revealed the superparamagnetic nature based on the trends on Vibrational Sample Magnetometer profiles. Cr3+(0.1 wt%): PEO + PVP polymer reveals high ionic conductivity in the order of 1.14 × 10−5 S/cm at 373 K. Dielectric constant behaviour has also been analysed with respect to frequency.