Performance test of Zn-astaxanthin complex-sensitized solar cell: effect of light intensity on open-circuit voltage and short-circuit current values

The sensitizer is one of the most essential dye -sensitized solar cell (DSSC) components. In the present research, a Znastaxanthin complex was investigated as a sensitizer, compared to pure astaxanthin. The complex with a 1:1 mole ratio between astaxanthin and Zn 2+ was synthesized in a reflux reactor at 37-60 degrees C. The product was analyzed using Proton Nuclear Resonance ( 1 H-NMR), which indicates the presence of chelate formation between Zn 2+ with two atoms of oxygen on the terminal cyclohexane ring of astaxanthin. The interaction of sensitizers (astaxanthin and Zn-astaxanthin) on the photoelectrode surface in this study was analyzed using a Fourier Transform Infra -Red (FTIR) and Ultraviolet -Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The FTIR spectra of photoelectrode immersed in Zn-astaxanthin show peaks of C=O stretching and vibration -OH group at 1730 and 1273 cm -1 , respectively, and H -C -H stretching vibration with high intensity in 2939, 2923, and 2853 cm -1 . The UV-Vis DRS analysis shows the band gap of photoelectrode (PE), photoelectrode immersed in astaxanthin (PE/astaxanthin), and Zn-astaxanthin (PE/Zn-astaxanthin) are 3.19, 1.65, and 1.59 eV, respectively. Under illumination intensity of 300 W/m 2 , the maximum energy conversion efficiency of DSSC with Zn-astaxanthin as sensitizer is (0.03 + 0.0022)%, higher than DSSC with astaxanthin as sensitizer ((0.12 + 0.0052)%). Up to 70 h of illumination, DSSC with Zn-astaxanthin as a sensitizer also has better stability than astaxanthin-based DSSC.