High Pyroelectric Properties of Porous Ba_0.67Sr_0.33TiO₃ for Uncooled Infrared Detectors

Abstract

Porous Ba0.67Sr0.33TiO3 (BST) ceramics were fabricated by the solid‐state reaction process, and their micro‐structural, dielectric, and pyroelectric properties were systemically investigated. Compared with dense specimens, porous BST exhibited a higher pyroelectric coefficient (p), a lower dielectric constant (ɛ), and heat capacity (CV), which are beneficial for the development of pyroelectric devices. At room temperature, as the porosity increased from 1.0% to 9.6%, BST ceramics' pyroelectric coefficient increased from 5000 to 8000 μc·(m2·°C)–1, the dielectric constant decreased from 12 000 to 8000, while the dielectric losses were <1.0% and the figure‐of‐merit increased from 11.0 × 10−5 to 27.0 × 10−5Pa−0.5. Improvement of pyroelectric property is benecial for the development of infrared detectors.

Enhanced pyroelectric properties of porous Ba0.67Sr0.33TiO3 ceramics fabricated with carbon nanotubes

“…For pyroelectric materials, porous ceramics have a lower heat capacity and dielectric constant. It has been reported that both porous PZT and BST materials have a higher figure-of-merit [9][10][11][12]. However, there are still problems with porous PZT pyroelectric materials.…”

“…(1) indicates that BST does not require to be polarized while being used as a dielectric bolometer; therefore, porous BST is a better candidate for pyroelectric applications. In our previous work, we have fabricated porous BST ceramics with poly (methyl methacrylate) (PMMA), which exhibit good dielectric and pyroelectric properties [12].…”

“…Pores depress PZT's pyroelectric coefficient [9][10][11], and it is difficult to fully polarize porous samples because of a large leakage current arising from the pores. BST has been widely used as dielectric bolometer [3,[13][14][15], and its pyroelectric coefficient can be obtained as follows [12,15,16]:…”

Intrinsic pyroelectric properties of thick, coarse grained Ba 1−x Sr x TiO 3 ceramics

“…Among pyroelectric materials, barium strontium titanate (Ba 1-x Sr x TiO 3 , BST) is intensively studied for several reasons: Sr is an effective solute for decreasing the paraelectricferroelectric phase transition temperature in a wide temperature range [12][13][14][15], leading to enhanced pyroelectric properties around room temperature; BST compositions are environmentally-friendly materials, which might represent viable alternatives to replace Pbbased oxides; the total pyroelectric coefficient can be very large in materials like BST, as shown in previous literature, especially due to the contribution of the induced part [16][17][18][19][20][21].…”

Fabrication and influence of sintering temperature on material properties of Mn/Y codoped Ba0.67Sr0.33TiO3 ceramics via using citrate–nitrate combustion derived powder

“…And the temperature at which the material displays its largest temperature sensitivity can be matched exactly to devices' ambient temperature simply by changing Ba/Sr ratio [6], which enables the devices for use close at room temperature. The major challenge in designing material systems for pyroelectric devices is the simultaneous requirement of a high pyroelectric coefficient, a low heat capacity, and low dielectric constant and loss [7]. Since material properties are strongly related to the microstructure of materials, fabricating homogeneous and uniform materials is important.…”