Study of reduced graphene oxide film incorporated of TiO 2 species for efficient visible light driven dye-sensitized solar cell Foo Wah Low 1 • Chin Wei Lai 1 • Sharifah Bee Abd Hamid 1 Received: 26 August 2016 / Accepted: 31 October 2016 Ó Springer Science+Business Media New York 2016 Abstract The hybrid reduced graphene oxide (rGO) with titanium dioxide (TiO 2 ) species photoelectrodes forming a TiO 2 –rGO nanocomposite (TiO 2 –rGO NC) was prepared using a simple hydrothermal technique to enhance their visible light dye-sensitized solar cells (DSSCs) perfor- mances compared with the pure reduced graphene oxide (rGO) photoelectrodes. This study aims to determine the optimum loading content of TiO 2 species on the rGO photoelectrodes for improving their visible response in terms of conductivity as well as photoconversion effi- ciency. A low content of TiO 2 (0.3 wt%) species was successfully incorporated into the rGO photoelectrodes lattice and formed a Ti–O–C bond, which significantly maximized the photocurrent generation efficiency and promoted a charge separation by trapping the photo-in- duced electrons with 7.2%, which is relatively high com- pared to the pure rGO photoelectrodes (0.67%). However, the excess TiO 2 species of 0.4 and 0.5 wt% resulted in poor photoconversion efficiency performance attributed to the over photocatalytic reaction occurred leaving extra holes on the counter electrode. Herein, a novel hybrid formation between rGO and TiO 2 nanomaterials by using the one-step hydrothermal technique in order to improve the DSSCs performance which brought a better conductivity, higher photoconversion efficiency (0.67–7.20%), and lower recombination of rGO material was introduced. 1 Introduction Nowadays, the public concern about the environment, cli- mate change, and limited fossil fuel resources have given rise to the urgent need of fostering development in the area of renewable energies which are inexhaustible and non- polluting. The renewable energy is one of the technologies to generate clean and green sources of energy to overcome the greenhouse gasses and global carbon emissions issues. The renewable energy was performed as the alternative energy sources which provide us energy in a sustainable manner. Recently, the photovoltaic solar era such as the dye- sensitized solar cells (DSSCs) was aroused instead of the conventional solar cell due to the large availability and low-cost of the ingredient material as well as low pro- cessing temperatures. This renewable energy technology enables the conversion of sunlight energy into useful electricity by generating electron and hole pairs (EHPs) in order to overcome the global warming issue instead of utilizing the conventional solar energy. During the past few years, significant efforts have been established by utilizing the reduced graphene oxide (rGO) in order to decrease the light harvest of dye molecules and improve the power efficiency of DSSCs [1, 2]. However, rGO as photoelectrode conducted in DSSCs device can only absorb 2.3% of visible light from the solar illumina- tion [3, 4]. Hence, the synthesis of rGO via solution pro- cessing as an efficient electrode in DSSCs will contain lattice defects [5]; grain boundaries that act as recombi- nation centres [6]. These several factors will result in the decrease of conductivity in the DSSCs construction. In order to further improve the immigration of photo- induced charge carriers and lattice defects, considerable efforts have to be exerted to further improve the rGO as & Chin Wei Lai cwlai@um.edu.my 1 Nanotechnology and Catalysis Research Centre (NANOCAT), Level 3, Block A, IPS Building, University of Malaya (UM), 50603 Kuala Lumpur, Malaysia 123 J Mater Sci: Mater Electron DOI 10.1007/s10854-016-5993-0