Blue-Coloured Highly Efficient Dye-Sensitized Solar Cells by Implementing the Diketopyrrolopyrrole Chromophore

The paradigm shift in dye sensitized solar cells (DSCs) - towards donor-pi bridge-acceptor (D-pi-A) dyes - increases the performances of DSCs and challenges established design principles. Framed by this shifting landscape, a series of four diketopyrrolopyrrole (DPP)-based sensitizers utilizing the donor-chromophore-anchor (D-C-A) motif were investigated computationally, spectroscopically, and fabricated by systematic evaluation of finished photovoltaic cells. In all cases, the Co(bpy)(3) redox-shuttle afforded superior performance compared to I-3(-)/I-. Aesthetically, careful molecular engineering of the DPP chromophore yielded the first example of a high-performance blue DSC - a challenge unmet since the inception of this photovoltaic technology: DPP17 yields over 10% power conversion efficiency (PCE) with the Co(bpy)(3) electrolyte at full AM 1.5 G simulated sun light.