Improved efficiency of quantum dot sensitized solar cells based on TiO2/rGO/TiO2 photoanode

• Using a mold to add a layer of rGO film between two layers of TiO 2 , which is different from the common doping of rGO quantum dots reported previously. • The addition of rGO layer bridged the crack of TiO 2 in the first layer, forming a network structure perfectly fit with the crack of TiO 2 . • Photoanode with TiO 2 / rGO / TiO 2 structure is advantageous for the separation, transmission and collection of photocarriers. • The QDSSC assembled by photoanode of this structure achieves higher short-circuit current density and PCE. While quantum dot sensitized solar cells (QDSSCs) have attracted great attention, the power conversion efficiency is still far from theoretical value. To address this issue, in present work, we introduced reduced graphene oxide (rGO) into the QDSSC photoanode, and prepared TiO 2 /rGO/TiO 2 photoanode structure. Due to the excellent conductivity of rGO, we optimized the built-in electric field in the electrode, and improved the ability for extraction, collection, and transfer of photogenerated electrons of the photoanode. Compared with cells without rGO inserting layer, the power conversion efficiency of cells based on TiO 2 /rGO/TiO 2 photoanodes is enhanced from 2.86% to 4.03%. This work provides a way for enhancing performance of QDSSCs.