Enhanced Charge-Carrier Mobility Derived from Cyclization of a Silanylene Unit on Dithienosiloles: Syntheses, Photophysical Properties, and Device Fabrication of Dithieno-spiro-siloles

Abstract

A series of trimethylsilyl-substituted dithieno-spiro-siloles (3), with a four- to six-membered silacycloalkyl substituent at the 1,1-position, were prepared by reacting 3,3′-dilithio-5,5′-bis(trimethylsilyl)-2,2′-dithiophene (2) with the corresponding silacycloalkyl dichlorosilane precursors (1). Arylamino-substituted bis(diarylamino)dithieno-spiro-siloles (6) were also prepared using the same synthetic protocol by reacting 3,3′-dilithio-5,5′-bis(diarylamino)-2,2′-dithiophene (5) with 1. A structural study of the five-membered dithieno-spiro-silole, 1,1-(silacyclopentenyl)dithieno-spiro-silole (3b), was undertaken and showed a reduced intermolecular distance in the solid state. This resulted in enhanced charge-carrier mobility, which was confirmed by a time-of-flight (TOF) measurement of 6b. The electronic properties of dithienosiloles (6) were studied for device fabrication by applying them as emitting materials in multilayer devices. Thus, I−V characteristics of multilayer devices, comprising N,N′-bis(...