Semiconducting pi-extended porphyrin dimer and its characteristics in OFET and OPVC

Abstract

Porphyrin is considered as one of the best candidates for various organic electronic devices, due to its molecular planarity and pi-conjugation. Particularly, for the good performing OFETs based on porphyrin derivatives, they should have high crystallinity and close pi-pi stacking distance in solid state. However, pi-extended dimeric porphyrin has never been introduced as a charge transport layer in OFETs. In this regard, we report here on the design and synthesis of new solution processable semiconducting pi-extended porphyrin dimer (PD-1), and its OFET and OPVC characteristics. Due to strong pi-pi. interactions, PD-1 showed high crystallinity in film state which displayed an excellent electrical characteristics with high hole mobility of 0.026 cm(2)/Vs and high current on off ratio of >10(5), when the device was fabricated in the mixed solvents of toluene and THF. This mobility is 1000 times better than that of a device fabricated from a solution either THF or toluene exclusively. Furthermore, the photovoltaic performance of PD-1 device shows a PCE of 0.58%. The effective pi-conjugation and molecular planarity of pi-extended dimeric porphyrin (PD-1) can lead to significant changes in the electrical characteristics of the devices. (C) 2015 Elsevier B.V. All rights reserved.