Porous organic polymers as emerging new materials for organic photovoltaic applications: current status and future challenges
Porous organic polymers are materials with covalently bonded (hydro)thermally stable backbones exhibiting high and accessible surface areas, and properties which are intriguing in the field of (opto)electronics. Especially in organic photovoltaics (OPVs), the electron rich backbone of this class of materials provides exceptional light absorption properties for improved charge formation/separation. Particularly for devices operating via bulk heterojunctions, the rigid open voids along the porous skeleton are rather interesting for improved phase separation and act as an ideal host to the prospective acceptors. Furthermore, their high dimensional geometry allows them to transport electrons/holes independent of orientation issues. However, the non-soluble nature of this class of materials limits their processability for forming uniform films, which is essential for device fabrication. In this review, a brief overview on the reported OPV devices fabricated by applying porous organic polymers in the active layer with the corresponding methods used for film formation will be presented, which will be followed by a discussion regarding possible improvements on the film formation methods and suggestions upon enhancement of the structural/electronic feasibility of the porous backbone.