Journal Article CsCl HNO3 N-type doping PEDOT:PSS Review Seebeck coefficient ambipolar transistors colloidal nanocrystals colloidal quantum dots conjugated polymers density of trap states dopant location doping electron‐transporting layers field effect transistors nanostructure materials organic photovoltaics organic thermoelectrics organic thin‐film transistors post‐treatment printed electronics self‐assembled monolayers solar cells solution processing solution-processable semiconductors thermoelectrics thin films thiol carbazoles transistors