Enhanced efficiency of organic photovoltaic cells with Sr2SiO4:Eu2+ and SrGa2S4:Eu2+ phosphors

We report the effect of yellow Sr2SiO4:Eu2+ and green SrGa2S4:Eu2+ phosphors on the efficiency of organic photovoltaic (OPV) cells. Each phosphor was coated on the back side of indium tin oxide (ITO)/glass substrates by spin coating with poly(methyl methacrylate) (PMMA). The maximum absorption wavelength of the active layer in the OPV cells was ∼512 nm. The emission peaks of Sr2SiO4:Eu2+ and SrGa2S4:Eu2+ were maximized at 552 nm and 534 nm, respectively. The short circuit current density (Jsc) and power conversion efficiency (PCE) of the OPV cells with Sr2SiO4:Eu2+ (8.55 mA/cm2 and 3.25%) and with SrGa2S4:Eu2+ (9.29 mA/cm2 and 3.3%) were higher than those of the control device without phosphor (7.605 mA/cm2 and 3.04%). We concluded that phosphor tuned the wavelength of the incident light to the absorption wavelength of the active layer, thus increasing the Jsc and PCE of the OPV cells.

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► The Jsc and PCE of the OPV cells with Sr2SiO4:Eu2+ are 8.55 mA/cm2 and 3.25%.
► The Jsc and PCE of the OPV cells with SrGa2S4:Eu2+ are 9.29 mA/cm2 and 3.3%.
► These values are higher than those of the control device without phosphor (7.605 mA/cm2 and 3.04%).