en گروه پلیمر Polymers Research Paper Research Paper <div style="text-align: justify;"><span style="font-size:11pt"><span style="line-height:150%"><span sans-serif="" style="font-family:Calibri,"><span new="" roman="" style="font-family:" times="">In this research, praseodymium (Pr) doped titanium oxide was deposited onto a glass substrate by nebulizer spray pyrolysis technique. The rare earth-doped thin film was subjected to studies on structural, morphological, optical, and gas sensing properties. The structural properties of the deposited thin films exhibit varied texture along with (101) direction. The grain size of the thin film varies with various mole percentages of doped TiO₂ thin films. As various doping concentrations increase, the prepared thin films show different optical properties like band gap, extension coefficient, refractive index, and dielectric constant. Fourier transform infrared (FTIR) results revealed that the reflectance spectra conformed to the existence of functional groups and chemical bonding. Gas sensing studies were carried out for undoped and Pr-doped TiO₂ films. The sensor was exposed to ethanol gas. The response of a TiO₂ thin film at different ethanol concentrations and different operation temperatures was studied. The gas sensitivity of ethanol gas was measured when the fast response of the film with 0.004M Pr-doped TiO₂ thin film showed a response time of 99 s and recovery time of 41 s, as well as the resistance falling to 0.6x10⁶&Omega;. The sensor operated at maximum effectiveness at an optimum temperature of 200&deg;C.</span></span></span></span><br> &nbsp;</div> ,Doped TiO2 thin films,structural properties,optical properties,gas sensor studies. 1 9 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-4583-1&slc_lang=en&sid=1 Revathi Baskaran revathib17@gmail.com 1800319475328460017800 1800319475328460017800 No PG and Research Department of Physics, Alagappa Government Arts College, (Affiliated to Alagappa University, Karaikudi) Karaikudi-630 003, India. Perumal Perumal perumal59@gmail.com 1800319475328460017801 1800319475328460017801 Yes PG and Research Department of Physics, Alagappa Government Arts College, (Affiliated to Alagappa University, Karaikudi) Karaikudi-630 003, India. Deivamani Deivanayagam deivamaniaac@gmail.com 1800319475328460017802 1800319475328460017802 No PG and Research Department of Physics, Alagappa Government Arts College, (Affiliated to Alagappa University, Karaikudi) Karaikudi-630 003, India.