Improved performance of a-Si:H solar cell by using up-conversion phosphors

Up-conversion is a promising technique for harvesting sub-band-gap photons in photovoltaic devices. The implementation and characterization of rare-earth doped up-converters on a-Si:H solar cells are investigated. Three up-conversion phosphors, beta-NaYF4:Yb3+ 20%/Er3+ 1%, beta-NaYF4:Yb3+ 25%/Ho3+ 1% and beta-NaYF4:Yb3+ 60%/Tm3+ 0.5%, are developed and employed as low energy convert materials for a-Si: H solar cells. Two different ways of adhering the up-converter to the a-Si:H solar cell have been implemented: by dissolving the powder in the polydimethylsiloxane (PDMS) and by compressing it into solid slice with a tablet pressing machine. The performance of a-Si:H solar cells integrating the up-converters is investigated under both 980 nm infrared laser diode and simulated solar light source (AM1.5G) illumination. The Current-Voltage measurements reveal that the beta-NaYF4:Yb3+ 20%/Er3+ 1% up-conversion phosphor performs both up-conversion and scattering functions in improving the overall performance of a-Si:H solar cell. (C) 2015 Elsevier B.V. All rights reserved.