A New Mussel-Inspired Polydopamine Sensitizer for Dye-Sensitized Solar Cells: Controlled Synthesis and Charge Transfer

The efficient electron injection by direct dye‐to‐TiO2 charge transfer and strong adhesion of mussel‐inspired synthetic polydopamine (PDA) dyes with TiO2 electrode is demonstrated. Spontaneous self‐polymerization of dopamine using dip‐coating (DC) and cyclic voltammetry (CV) in basic buffer solution were applied to TiO2 layers under a nitrogen atmosphere, which offers a facile and reliable synthetic pathway to make the PDA dyes, PDA‐DC and PDA‐CV, with conformal surface and perform an efficient dye‐to‐TiO2 charge transfer. Both synthetic methods led to excellent photovoltaic results and the PDA‐DC dye exhibited larger current density and efficiency values than those in the PDA‐CV dye. Under simulated AM 1.5 G solar light (100 mW cm−2), a PDA‐DC dye exhibited a short circuit current density of 5.50 mW cm−2, corresponding to an overall power conversion efficiency of 1.2 %, which is almost 10 times that of the dopamine dye‐sensitized solar cell. The PDA dyes showed strong adhesion with the nanocrystalline TiO2 electrodes and the interface engineering of a dye‐adsorbed TiO2 surface through the control of the coating methods, reaction times and solution concentration maximized the overall conversion efficiency, resulting in a remarkably high efficiency. Flex your mussels: An efficient electron injection by direct dye‐to‐TiO2 charge transfer of new synthetic mussel‐inspired polydopamine dyes deposited on a TiO2 surface is reported. The dyes show strong adhesion with the photoelectrode and interface engineering of a dye‐adsorbed TiO2 surface maximizes the overall conversion efficiency (see figure).