Charge Transport Characteristics of Surface‐Complexed Quantum Dot in a Thin Film Transistor

Abstract

Ambipolar transport characteristics of thin film transistors fabricated from nontoxic white light emitting quantum dot complexes (QDCs) are herein reported to exhibit efficient carrier mobilities. The QDCs are synthesized by forming bluish green emitting zinc quinolate complex on the surface of orange emitting Mn2+-doped ZnS quantum dots (Qdots) using 8-hydroxyquinoline 5-sulfonic acid as the chelating ligand. The device exhibits efficient ambipolar transport characteristics with high ION/IOFF ratio of 104 and electron mobility and hole mobility of 2.95 × 10−02 and 1.06 × 10−02 cm2 V−1 s−1, respectively. The subthreshold slope of Qdot complex–integrated thin film transistor increases from that of Mn2+-doped ZnS Qdot–integrated thin film transistor from 0.35 to 0.79 V dec−1 in p-field effect transistor (FET) and from 0.59 to 0.97 V dec−1 in n-FET operations, which annotates an increase in trap state density due to surface complexation of the Qdot. These results suggest that white light emitting QDC can be used as an efficient transport as well as an emissive material, which open up new paradigm for advanced optoelectronic applications.