Absorption, Emission and Stability Investigations on Insulating

eng Ansari Education and Research Society Journal of Ultra Chemistry 0973-3450 2319-8036 August 2026 22 3 29 39 http://dx.doi.org/10.22147/juc/220301 933 article Absorption, Emission and Stability Investigations on Insulating - Conducting Polymer Blends G. RAJESHA SHETTY 1 SHREEDATTA HEGDE 2 VINAYAK BHAT 3 BHARAMAGOUDA PATIL 4 ISHWAR NAIK 5 Department of Physics, Maharaniu2019s science College for Women (Autonomous), Mysuru 570005 (India) Department of Physics, Government First Grade College for Women, Balmatta, Mangaluru - 575001 (India) Department of Physics, Dr. A, V. Baliga College of Arts and Science Kumta-581343 (India) Department of Physics Government First grade College Hubballi-580032 (India) Dept. of Physics, Government First Grade College Kumta- 581343 (India) <p>Insulating -conducting polymer blends exhibit fascinating optical properties. Poly [2-methoxy-5(3’, 7’- dimethyloctyloxy)-1, 4- phenylenevinylene] [MDMO-PPV] is a widely used conducting polymer with band gap of about 2eV. The thin films of MDMO-PPV prepared from chloroform has the absorption maximum at about 490nm and emission maximum at around 590nm. We have prepared free standing films of MDMO-PPV doped at 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt% and 3.0wt % of 1:1 PMMA/PVAc non conducting polymer matrix by solution cast method. Absorption peaks are slowly red shifted from 499.4nm for 0.5 wt% sample to about 514.2nm for 3.0 wt% sample. Red shift is also observed in emission spectrum (fluorescence spectrum) ranging from 586nm to about 593nm with the increased doping level. Considerable Stoke’s shift has been noticed which plays an important role inhibiting fluorescence quenching. New material exhibits multiband gap structure that are calculated using Tauc’s plot. Least direct band gap of 1.93 eV and indirect band gap of about 1.27eV are noticed. Thermogravimetric and Differential Scanning calorimetry affirmed slight variations in the stability of the samples compared to that of pure PMMA/PVAc films. There is no such drastic change in the thermal stability, may be because of very small variation in the doping concentrations. Observed broad band absorption and also efficient emission in the visible region along with the tailored absorption -emission properties can be used in the designing a new materials of desired properties.</p> https://journalofchemistry.org/paper/933/ MDMO-PPV PMMA PVAc Stokeu2019s shift