Enhanced light harvesting with novel photon upconverted Y2CaZnO5:Er3+/Yb3+ nanophosphors for dye sensitized solar cells

Abstract Trivalent erbium (Er 3+ ) and erbium-yttribium (Er 3+ /Yb 3+ ) co-doped Y 2 CaZnO 5 (YCZ) nanophosphors were synthesized via Sol-Gel combustion method and applied as photon up-converter in dye sensitized solar cell (DSSC) and studied for their photovoltaic properties. A bright green and green–red up-conversion emission is observed upon an excitation of 980 nm in Er 3+ :YCZ and Er 3+ /Yb 3+ :YCZ nanophosphors, respectively which indicates the possibility of using these phosphors for light harvesting applications. The prepared Er 3+ and Er 3+ /Yb 3+ co-doped YCZ nanophosphors were incorporated in TiO 2 based DSSC to form the composite photoelectrode and studied the power conversion efficiency (PEC). With the incorporation of Er 3+ and Er 3+ /Yb 3+ co-doped YCZ nanophosphors in the DSSC resulted in the enhanced PCE of 6.01% and 7.21% using durable methoxypropionitrile (MPN) and volatile acetonitrile (AcN) based electrolytes, respectively. The PCE values obtained for the studied compounds are found to be either comparable or better than the other reported compounds used for the light harvesting. An enhanced photocurrent (J SC ) of 12.44 and 13.28 mA/cm 2 , for Er 3+ :YCZ and Er 3+ /Yb 3+ :YCZ nanophosphors based DSSC, respectively was observed under AM1.5 G light due to the better photon conversion efficiency of the nanophosphor. The detailed up-conversion (UC) mechanism responsible for the enhanced PCE properties were discussed in detail and the results were compared with similar phosphor systems.