Effect of semi-perfluoroalkyl chains on A-DA′D-A type small molecule acceptor in organic solar cells

Herein, a new A-DA ' D-A structured small molecule acceptor named m-TF9, containing semi-perfluoroalkyl chains, was designed and synthesized for highly efficient organic solar cells (OSCs). Compared with its alkylsubstituted analogous m-TH, m-TF9 exhibits tighter molecular packing and lower surface free energy. When blended with PTQ10, m-TF9 can achieve a high fill factor of 77.3%. By using 1,4-difluorobenzene as an additive, the PTQ10:m-TF9-based OSC delivers a high efficiency of 16.3% with an improved short circuit current (J(SC)) of 27.0 mA cm(-2). In addition, the m-TF9-based OSC demonstrates good storage stability in both air and nitrogen environments. This work highlights the great potential of semi-perfluoroalkyl chains as the modification blocks for A-DA ' D-A type acceptors to achieve good charge transport properties and high efficiency.