Simultaneously achieving superior pyroelectric performance and ultrahigh depolarization temperature in NaNbO3-based ceramics

Pyroelectric materials have been widely studied because of their important role in infrared detectors, sensors, thermal imaging, and other applications, among which, lead-based ceramics are extensively adopted. However, the environmental problems caused by lead-based compounds in production and processing are becoming increasingly serious. Meanwhile, the surface mounting technology is extensively employed in the electronics industry for device miniaturization and integration. However, due to its high processing temperature (similar to 260 degrees C), it makes most pyroelectric ceramic materials unsuitable for this process. Therefore, it is of great significance to develop novel high-performance lead-free pyroelectric ceramics with high depolarization temperature (>260 degrees C). In this work, we report the Na0.995Ag0.005NbO3-0.1%Mn (NANM) pyroelectric ceramics. The antiferroelectric-ferroelectric phase transition field and coercive field of NaNbO3 ceramics were reduced by the introduction of AgNbO3 and Mn, making it easier to induce the ferroelectric phase and realize poling in NANM ceramics. The NANM ceramics exhibited an excellent pyroelectric coefficient of 2.55 x 10(-4) C m(-2) K-1 and figures of merit as F-i = 0.93 x 10(-10) m/V, F-v = 6.46 x 10(-2) m(2)/C, and F-d = 2.92 x 10(-5) Pa-1/2 at room temperature. More importantly, a high depolarization temperature of 280 degrees C was achieved, ensuring the ability to withstand high temperature during production and operation. The NANM ceramics with excellent pyroelectric properties and high depolarization temperature are expected to be a promising lead-free candidate for uncooled infrared detector applications.