All-in-one single-piece flexible solar thermoelectric generator with scissored heat rectifying p-n modules

Junctions existing in conventional thermoelectric generators (TEGs) may lower their output power by increasing the internal resistances and reduce their flexibility, especially for organic TEGs. In this paper, we reported a new junction free all-in-one single-piece (SP) solar thermoelectric generator which was scissored from a free-standing carbon nanotube thin film with patterned p/n modules. In addition, a heat-rectifying structure has been designed to increase the temperature gradient between the hot/cold side of the TEG. A high sunlight-to-electricity output power of 1709.2 nW was obtained for the SP device, which is about 4.5 times higher than that of the conventional-structure TEG (Con-TEG). The highest output power density of this SP device is about 83 times higher than that of the Con-TEG because this fully organic SP device does not contain heavy metal moieties as connectors that typically appear in the Con-TEGs. Moreover, the junction-free SP device exhibited excellent flexibility which can be bent for 1000 times without noticeable decay and fluctuations in its conductance. While the Con-TEG cracked after being bent for only 100 times. The results indicate a promising way for developing high performance flexible organic thermoelectric devices.