Improvement of thermal stability of an organic pyroelectric infrared sensor with Parylene C coating

Abstract

We fabricated a protective Parylene C layer coated with vinylidene fluoride (VDF) oligomer thin films to improve their thermal stability and investigated the temperature dependence of their pyroelectric properties. Following the heat resistance test (at 398 K for 500 h in the presence of air at atmospheric pressure), the deterioration of voltage sensitivity of the Parylene C coated sensor was approximately 20% (553 → 430 V W-1) and approximately 100% in the case of the sensor without Parylene C (551 → 0.86 V W-1). Parylene C coating prevented structural disturbances of VDF oligomer thin films and electrode cracking. Comparison of the VDF oligomer, Parylene-C-coated VDF oligomer, and Parylene-C-coated P(VDF-TrFE), demonstrated the superior thermal stability of the Parylene-C-coated VDF oligomeric pyroelectric sensor.