Enhanced Pyroelectric Performances in Textured Na_0.5Bi_4.5Ti₄O₁₅ Ceramics for Infrared Detection

The pyroelectric effect is extensively used in infrared imaging, detection systems, military equipment, and smart furniture, which require pyroelectric materials to simultaneously possess a high pyroelectric coefficient (<i>p</i>) and a high Curie temperature (<i>T</i>_c) for circuit integration. However, the <i>T</i>_c of commercial lead zirconate titanate (PZT) is limited to 230 °C, imposing an insurmountable challenge in the integration. Here, we investigated the pyroelectricity in Na_0.5Bi_4.5Ti₄O₁₅ (NBT) with a high Curie temperature (∼660 °C), meeting the temperature requirements for integration. Textured NBT ceramics with a high degree of orientation (80%) were fabricated by using tape-casting, resulting in a <i>p</i> of 122 μC m^-2 K^-1, a 144% improvement over randomly oriented NBT ceramics. This method was also applied to doped NBT ceramics (NBTM-5Nb), achieving an impressive <i>p</i> of 252 μC m^-2 K^-1, representing a 400% improvement compared to randomly oriented NBT ceramics. Meanwhile, the textured NBTM-5Nb ceramics exhibit excellent figures of merit with <i>F</i>_i = 1.05 × 10^-10 m V^-1, <i>F</i>_v = 0.09 m² C^-1, <i>F</i>_d = 4.9 × 10^-5 Pa^-1/2, comparable to the performance of PZT. Furthermore, the textured ceramics exhibit excellent thermal stability, with no performance degradation after annealing at 300 °C, rendering them suitable for circuit integration.