Electrical Transport Characteristics of Chemically Robust PDPP-DTT Embedded in a Bridged Silsesquioxane Network

Chemical robustness of solution-processed polymer semiconductor films against various chemical solvents plays a critical role in realizing the low-cost fabrication of functional devices in tandem structures. This has been recently obtained by constructing a semi-interpenetrating diphasic polymer network (s-IDPN) comprising a bridged silsesquioxane (BSSQ) framework with an embedded polymer semiconductor. Despite the disruption in the ordering of polymers induced by the BSSQ framework, the electrical transport characteristics of the s-IDPN film turned out to be superior to those of the pristine polymer film. As a case study, we examined the temperature-dependent electrical transport characteristics of poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno[3,2-b]thiophene)] (PDPP-DTT) embedded in a bridged silsesquioxane (BSSQ) framework. The enhanced transport through PDPP-DTT in the s-IDPN structure is associated with the increased short-range ordering of the polymers embedded in the BSSQ framework and the chemical doping effect provided by the framework, which altogether concentrate the density of states for PDPP-DTT effectively involved in hole transport.