F. Weiting and Y. Yixun. Temperature effects on the refractive index of lead telluride and zinc selenide, Infrared Phys.30, 371-373, 1990 (fitting experimental data with dispersion formula: refractiveindex.info)
Lead telluride (PbTe) is a narrow bandgap semiconductor with significant thermoelectric properties, making it particularly valuable for applications in thermoelectric power generation and cooling systems. Due to its ability to convert waste heat into electricity, PbTe-based thermoelectric materials are explored for use in various energy-harvesting applications, such as automobile exhaust systems and industrial waste heat recovery. Additionally, PbTe's responsiveness to infrared radiation has led to its employment in infrared detectors and sensors. However, the material's use is limited by the inherent toxicity of lead, necessitating careful handling and disposal.