Thermal Quenching Mechanism of Metal–Metal Charge Transfer State Transition Luminescence Based on Double-Band-Gap Modulation
Qincan Ma, Qiang Zhang, Mei Yang, Baiqi Shao, Ruizhuo Ouyang, Ning Guo
Abstract
Bi3+-related metal-to-metal charge transfer (MMCT) transition phosphors are expected to become a new class of solid-state luminescent materials due to their unique broadband long-wavelength emission; however, the main obstacle to their application is the thermal quenching effect. In this study, one novel thermal quenching mechanism of Bi3+-MMCT transition luminescence is proposed by introducing electron-transfer potential energy (ΔET). Y0.99V1–xPxO4:0.01Bi3+ (YV1–xPxO4:Bi3+) is used as the model; when the band gap of the activator Bi3+ increases from 3.44 to 3.76 eV and the band gap of the host YV1–xPxO4 widens from 2.75 to 3.16 eV, the electron-transfer potential energy (ΔET) decreases and the thermal quenching activation energy (ΔE) increases, which result in the relative emission intensity increasing from 0.06 to 0.64 at 303–523 K. Guided by density functional calculations, the thermal quenching mechanism of the Bi3+-MMCT state transition luminescence is revealed by the double-band-gap modulation model of the activator ion and the matrix. This study improves the thermal quenching theory of different types of Bi3+ transition luminescence and offers one neo-theory guidance for the contriving and researching of high-quality luminescence materials.