Electrical measurements performed on films of bare carbon quantum dots (CQDs) as well as of CQD functionalized with PEG(1500N) deposited on interdigitated electrodes reveal a significant resistance hysteresis. At room temperature, both systems present a stable memory effect after a large number of cycles, fact associated with the removal of shallow trapping states after the thermal treatment of bare and passivated CQDs films. Temperature analysis of transport properties shows that CQDs functionalized with PEG(1500N) present a stable hysteresis as the temperature increases, in contrast to the hysteresis of bare CQD films, which disappears at high temperatures. Several transport mechanisms responsible for the electrical behavior of these systems were analyzed and the role of PEG(1500N) as a passivation shell was discussed. (C) 2014 Elsevier B.V. All rights reserved.