I have no experience with CNT,but DMF,MEK I find are good solvents for graphene.Also, there are several polymer binders or binders especially for Silicon,mentioned in literature.Please check
DMF and NMP are good solvents for CNTs. However they are not related with the adhesion strength between CNT and Si wafer. In order to deposit the CNTs onto Si wafer by spin coating, you have to modify Si wafer surface with amine layer.