Porogen induced formation of mesoporous zinc ferrite thin films and their chemiresistive properties

Highlights: • Porous ZnFe₂O₄ thin films were successfully deposited using NH₄Cl as porogen. • Pore formation mechanism is illustrated. • The deposited chemiresistor has superior SO₂ gas sensitivity at 150 °C and excellent glucose sensitivity at room temperature. • The chemiresistive sensing performance is significantly improved due to porogen activity. The semiconducting metal oxides are the most studied chemiresistive sensing materials. Their surface morphology plays an important role in sensing response. The porous nature of the material can significantly enhance their sensing ability. With this aim, ZnFe₂O₄ thin films were deposited on glass substrates by spray pyrolysis technique. The added NH₄Cl porogen made pores in the film. The chemiresistive response of these porogen induced films for SO₂ gas and liquid glucose were found better as compared to compact films; which were deposited without porogen. The reaction mechanism and pore formation are explained in the paper.