Modification of photoelectrode with thiol-functionalized Calixarenes as interface energy barrier for high efficiency in dye-sensitized solar cells
AkIn, S.; Gülen, M.; Sayin, S.; Azak, H.; Yildiz, H.B.; Sönmezoʇlu, S.
We successfully synthesize a series of bis-thiol-substituted calixarene derivatives bearing diverse groups on the upper-rim/lower-rim ([email protected], [email protected], [email protected], [email protected], [email protected]). For the first time, we apply these derivatives as interface modifiers for improving the photovoltaic response of a Ru-bipy dye (N-719)-sensitized TiO2 photoanode in dye-sensitized solar cells (DSSCs). We use FT-IR, H- and C-NMR, UV-vis spectrophotometry, and elemental analysis techniques to characterize the structures oof the calixarene derivatives. We achieve an overall photon-to-electron conversion efficiency (PCE) of 12.97% with the DSSCs based on 25,27-bis(5-thiol-1-oxypentane)-26,28-dihydroxycalixarene ([email protected])-modified TiO2 photoanode (Jsc = 9.49 mA cm-2, Voc = 672 mV, FF = 61.1%) compared with a system of bare TiO2 (PCE: 6.82%) under AM 1.5G illumination of 300 W/m2. In addition, we also study the influence of the chain length ([email protected]; with 3 carbons and [email protected]; with 5 carbons) and subsidiary ligand groups such as alkyl ([email protected]), nitro ([email protected]), and amine ([email protected]) on the surface morphology, spectral response, and photovoltaic performance. Our results reveal that the [email protected] calixarene is the best derivative for modifiying the TiO2 photoanode. Thiol-functionalized Calixarene molecules play a role in assisting charge separation and preventing back recombination, which accounts for the observed enhancement in photovoltaic performance. © 2016 Elsevier B.V. All rights reserved.... Show more Show less