Langmiur–Blodgett studies of silicon(IV) phthalocyanine bis(trihexylsilyoxide) and its optical properties

Although much solution-based research has been carried out on silicon phthalacyanines, little work has been done on Si Pc LB films. In order to attempt studies on thin films, ultrathin Langmuir–Blodgett films of silicon(IV) phthalocyanine bis(trihexylsilyoxide), C68H94N8O2Si3 have been studied and characterised. Whilst silicon(IV) phthalocyanine bis(trihexylsilyoxide) is not a traditional LB film forming material, it can be made conducive to deposition by mixing with ideal film forming materials such as calixarenes. Surface pressure–area isotherms revealed an area per molecule of around 7.5 Å2 which indicates that the silicon(IV) phthalocyanine bis(trihexylsilyoxide) forms multi-lamella stacks. Thermal optical polarised spectroscopy revealed the formation of brightly coloured mesophases in films. DSC showed the presence of an irreversible A phase and a reversible T phase.