Photoinduced charge-carrier modulation of inkjet-printed carbon nanotubes via poly(vinyl acetate) doping and dedoping for thermoelectric generators

Highlights: • Photoinduced charge-carrier modulation of carbon nanotubes is achieved. • The dedoping mechanism is discussed from primary structure change of PVAc. • A thermoelectric module is obtained by photopatterns of carbon nanotubes. Here, we studied the charge-carrier modulation of single-walled carbon nanotubes (SWCNTs) via poly(vinyl acetate) (PVAc) doping and dedoping under ultraviolet (UV) light irradiation with the aim of pairing several p- and n-type SWCNTs as thermoelectric (TE) elements. The Seebeck coefficient of the SWCNTs was first made negative by doping with PVAc and then made positive again through UV-induced PVAc dedoping. A possible TE module configuration and the process for its fabrication are proposed, wherein prints and photopatterns can be obtained without the use of additional electrodes. Our findings enable the fabrication of fine TE modules using simple materials and techniques.