High Efficiency Nonfullerene Polymer Solar Cells with Thick Active Layer and Large Area

In this work, high-efficiency nonfullerene polymer solar cells (PSCs) are developed based on a thiazolothiazole-containing wide bandgap polymer PTZ1 as donor and a planar IDT-based narrow bandgap small molecule with four side chains (IDIC) as acceptor. Through thermal annealing treatment, a power conversion efficiency (PCE) of up to 11.5% with an open circuit voltage (V_oc) of 0.92 V, a short-circuit current density (J_sc) of 16.4 mA cm⁻², and a fill factor of 76.2% is achieved. Furthermore, the PSCs based on PTZ1:IDIC still exhibit a relatively high PCE of 9.6% with the active layer thickness of 210 nm and a superior PCE of 10.5% with the device area of up to 0.81 cm². These results indicate that PTZ1 is a promising polymer donor material for highly efficient fullerene-free PSCs and large-scale devices fabrication.

The nonfullerene polymer solar cells based on a wide bandgap polymer PTZ1 and a narrow bandgap acceptor IDIC exhibit weak active layer thickness and area dependence with the optimal power conversion efficiency of 11.5%, indicating that the blend of PTZ1/IDIC is potential for the practical application of polymer solar cells.

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