▎ 摘　　要

Graphene dots (GDs) are used for enhancing the performance of the poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS)-based counter electrodes in Pt-free dye-sensitized solar cells (DSSCs). As compared to PEDOT:PSS CEs, GD-PEDOT:PSS films possess a rough surface morphology, high conductivity and electrocatalytic activity, and low charge-transfer resistance toward I-/I-3(-) redox reaction, pushing cell efficiency to 7.36%, which is 43% higher than that of the cell with PEDOT:PSS CEs (5.14%). Without much impact on efficiency, the DSSCs with GD-PEDOT:PSS CEs work well under low-light conditions (light intensity <13.5 mW cm(-2) and angle of incidence >60), such as indoor and low-level outdoor lighting and of the sun while the other traditional cells would fail to work. The concurrent advantage in low cost in Pt free materials, simple fabrication processes, comparable efficiency with Pt CEs, and high performance under low-light conditions makes the DSSC with GD-PEDOT:PSS CEs suitable to harvest light for a diverse range of indoor and low-level outdoor lighting locations. (C) 2015 Elsevier Ltd. All rights reserved.