In the present investigation, anatase TiO2 nanofibers with various diameters have been synthesized by electrospinning technique. The electrospinning feeding rate has been varied from 1.0, 1.5, 2.0 and 2.5 ml. h(-1) in order to control the diameter of TiO2 nanofibers. The synthesized nanofibers are characterized by X-ray diffraction (XRD), field emission scanning-and high resolution transmission electron microscopy (FESEM-HRTEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements. From FESEM and XRD results it is clear that, the nanofibers diameter and crystallinity increases with respect to increasing feed rate. The synthesized nanofibers having various diameters further used for dye sensitized solar cells (DSSCs) application. Our controlled results show that, the nanofibers deposited at 1.5 ml. h(-1) feeding rate exhibits promising 5.39% power conversion efficiency (PCE) with short circuit current density (JSC) 13.32 mAcm(-2) and open circuit voltage (V-oc) = 0.698V. The detailed interface and transient properties of these nanofibers based DSSCs devices have been analyzed by electrochemical impedance spectroscopy (EIS), intensity modulated photocurrent/voltage spectroscopy (IMPS/IMVS) and open circuit voltage decay (OCVD) measurements. (C) 2015 Elsevier Ltd. All rights reserved.