MOF/Up-converting combination for photovoltaic application

Abstract It is imperative to transform the sub-bandgap photons into higher energy photons that can significantly enhance the efficiency of the photovoltaic device. Upconverting nanoparticles (UCNPs), combine (sub-bandgap) photons to give high-energy photons. Hexagonal UCNPs of β-NaYF4 concurred with Yb3+ and Er3+ were prepared via thermal decay of metals trifluoroacetate precursors. A solvothermal method was used for the preparation of Ru3-(BTC)2 MOF. The precursors were mixed in a molar ratio 3RuCl3xH2O: 2H3btc:5CH3COOH: 925H2O. The prepared materials were characterized by X-ray diffraction, SEM, TEM, UV–V is absorption, and emission spectra. The solar cell ZnO/MOF/UCNPs Electrode was prepared by the deposition of MOF on the ZnO electrode by the spin coating method and annealed at 200 °C for 2 h. Then this electrode was immersed into 40 mM UCNPs for 24 h then heated to 400 °C to form a compact layer of UCNPs. The impact of β-NaYF4:Yb3+, Er3+ UCNPs on the performance of ZnO/MOF photoelectrode was studied through solar cell assembly in a sandwich structure. The results showed that the UCNPs-based MOF-solar cell exhibited a 15.6% increase in the photocurrent and a 22% increase in the power conversion efficiency compared with MOF sensitized solar cell (MOFSSC) without UCNPs. This enhancement could be due to the presence of the UCNPs that extends the spectral response range of MOF-SSC to the NIR region. So integrating up-converting materials into MOF-sensitized solar cells would generate a new kind of highly efficient solar cells that realize the utilization of the solar light energy in a broad spectrum from the UV to the NIR region.