Role of long persistence phosphors on their enhancement in performances of photoelectric devices: In case of dye-sensitized solar cells

To enhancing enhanced sunlight harvesting, long persistence phosphor (LPP) materials were often incorporated into photoanodes of photoelectric devices. However, the role of LPP layer on the photoelectric enhancements is not yet clear. Here, the authors have systematically studied the effect of green LPP (SrAl₂O₄: Eu³⁺) and its thickness on photoelectric behaviours of dye-sensitized solar cells (DSSCs). Results showed that the P25/LPP DSSCs generates power conversion efficiency (PCE) of 7.16% at the optimal LPP thickness, which is 24.3% higher than that of the P25 ones. Series of analysis indicate that the enhancements in short-circuit current density and PCE could mainly be due to the LPP's function of back scattering (containing down-conversion effect and enhancement in light absorption) of incident sunlight. Moreover, the enhanced carriers’ lifetime and open-circuit voltage are mainly due to the LPP layer's afterglow effect. In addition, the P25/LPP DSSCs can still generate an output power density (82.15 μW cm⁻²) with a high PCE value of 46.94% in dark.