Biodegradable silk proteins have been demonstrated to function as edible optical components including diffraction gratings and lenses, as well as silk-based biosensors. Now, researchers at Consiglio Nazionale delle Ricerche (CNR; Bologna, Italy) and Tufts University (Medford, MA) have successfully integrated silk proteins into organic light-emitting transistors (OLETs) in a broader effort to move toward “eco-sustainable” practices in optoelectronics manufacturing.

To fabricate the OLETs, the team initially fabricated n- and p-type silk organic field-effect transistors (OFETs) by spincoating a water-insoluble, 400-nm-thick film of silk fibroin onto an optically transparent glass/indium tin oxide (ITO) substrate. Organic semiconductor layers and top metal contacts completed the OFET devices, which exhibited lower voltage thresholds and nearly no electrical hysteresis when compared to polymethylmethacrylate (PMMA)-based OFETs. Finally, the best p-type OFET was used to construct a unipolar OLET device. With a forward voltage of 90 V, the light-emission intensity was recorded at 100 nW, demonstrating the first observation of electroluminescence emission from an OLET device using silk as the gate dielectric material. Contact Roberto Zamboni at zamboni@isof.cnr.it.