Ca2HfSi4O12:Eu2+: A novel blue phosphor with excellent temperature sensitivity for temperature sensor and cathodoluminescence properties for field-emission displays

Abstract

A new silicate blue phosphor Ca2HfSi4O12:Eu2+ (CHSO:Eu2+) was designed and synthesized via a solid-state reaction. The structure of CHSO:Eu2+ was analyzed by structure refinement. The electronic structure of CHSO was calculated using first-principles calculations, revealing its effect on luminescence and long-persistent properties. Owing to the O vacancies in the crystal structure, undoped CHSO showed wide blue emission (400–650 nm, λmax = 486 nm) under 296 nm excitation. After being irradiated with a UV lamp for 10 min, the CHSO sample showed obvious afterglow properties that could persist for approximately 50 min above the recognizable intensity level (≥0.32 mcd m−2). CHSO:Eu2+ exhibited excellent temperature sensitivity with a relative sensitivity of 4.5 % K−1@473K, which is higher than those of other Eu2+-based temperature sensor materials. The mechanism between thermal quenching and electronic structure was proposed. Moreover, CHSO:Eu2+ shows excellent cathode ray saturation and aging resistance. This study provides a potential temperature sensor, field-emission-display material, and theoretical reference for developing high-sensitivity temperature-sensing materials.