Near-infrared quantum-cutting and long-persistent phosphor Ca3Ga2Ge3O12: Pr3+, Yb3+ for application in in vivo bioimaging and dye-sensitized solar cells

Abstract

Either quantum-cutting luminescence (QCL) or long-persistent luminescence (LPL) phosphor has been attracted attention for practical applications. Due to the real-time excitation source (low efficiency) for the QCL (LPL) process, both QCL and LPL have their own shortcomings. By combining the inherent properties of QCL and LPL, we devise a concept of QCLPL (quantum cutting long persistent luminescence), which can obtain high efficient LPL (at least > 100%). Germinate Ca3Ga2Ge3O12 (CGG) is chosen as matrix due to its low phonon frequency. Pr3+ is selected as donor (D) ion owing to its ladder-like arranged energy levels which facilitate the photon absorption and subsequent energy transfer (ET). Yb3+ ion is codoped as acceptor (A) ion due to its absorption and emission in near-infrared (NIR) region. Since the “optical transmission window” of biological tissues within 700–1100 nm allows for deeper light penetration, the QCLPL CGG: Pr3+, Yb3+ (CGGPY) results in increasing bioimage contrast. Meanwhile, as a down-conversion luminescent medium, CGGPY transfers UV light to NIR light, which increases the solar light harvest and photocurrent of dye-sensitized solar cells (DSSCs). Altogether, the strategy of combination of QCL and LPL processes in one host lattice has important implications for infrared lighting, DSSCs, bioimaging and et al.