Applications Of High Performance Relaxor Ferroelectric Single Crystals In Pyroelectric Infrared Detectors

As the science and technology develop,,infrared detection technology is more and more widely used in production and life.The infrared detectors based on pyroelectric effect have the characteristics of simple equipment,wide response range,low power consumption and low crosstalk.The application of non-dispersive infrared gas detection is the research focus of infrared detection technology.As the core of pyroelectric infrared detection system,the performance of pyroelectric materials plays a decisive role in the detection ability of the detectors.Mn doped relaxor ferroelectric single crystals Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-Pb Ti O₃（slightly Mn-doped PIMNT）have excellent comprehensive properties and are expected to become a sensitive element material for the next generation pyroelectric detectors.In this paper,the studies on Mn-doped PIMNT（21/49/30）relaxor ferroelectric single crystals and their applications in pyroelectric infrared detectors were carried out extensively.The research results are as follows:（1）The structure and properties of rhombohedral Mn-doped PIMNT（21/49/30）single crystals were studied.Compared with binary Mn-doped PMNT single crystals,the depolarization and temperature stability were improved.High figures of merit（FOMs）for detectivity F_d reach to 22.3×10^-5 Pa^-1/2,and the pyroelectric performance is much better than that of traditional pyroelectric materials.（2）The theoretical model of Mn-doped PIMNT（21/49/30）current mode pyroelectric detectors was established and optimized,and the photothermal and thermoelectric conversion processes of pyroelectric detector were analyzed.By simulation,the thickness and area of the sensitive element are determined to be 25μm and 4 mm,and feedback resistance₁)and feedback capacitance₁)are also determined,which are 50 GΩand 0.2 p F respectively.The frequency response of the detector’s responsivity₍（1）,noiseand specific detectivity^*were simulated,which provides a direction for the design and optimization of the detector.（3）Uncompensated and compensated current mode pyroelectric detectors were fabricated by using Mn-doped PIMNT（21/49/30）single crystals.The^*of two detectors were 1.17×10⁹ cm Hz^1/2 W^-1 and 1.01×10⁹ cm Hz^1/2 W^-1 respectively.The performance parameters of the uncompensated detector were consistent with the results of theoretical simulation.The parallel compensation optimization of the detector can greatly improve its vibration stability and temperature stability.A CO₂ gas sensor with a range of 0-5359 ppm was developed,of which the error is within 12 ppm±2.6%of reading,the sensitivity and the 50%response time are 50 ppm and 57 s respectively.