This research modified a porous titanium dioxide (TiO2) dye-sensitized solar cell (DSSC) with reduced graphene oxide (rGO) to improve efficiency. A secondary color selectivity effect was obtained by addition of an organic Fabry-Perot (F.P.) cavity. The TiO2 was doped with a variety of rGO including 0, 1, 5, and 10 wt%. Small molecule (McFarland and Tang, 2003; McFarland and Tang, 2003) 6,6-phenyl-C61-butyric acid methyl ester (PCBM) and polymer poly(3,4-ethylenedioxyselenophene): poly (styrene sulfonate) (PEDOS: PSS) were used to create the F.P. cavity. Such organic F.P. cavities on DSSCs can be produced by solution process which is economical, rapid, and produces a large surface area. The devices are suitable for use under low illumination indoor photovoltaic because there is light conversion current under low voltage. The solution process had three parts: (i) using a modified Hummers' method, the rGO was doped onto the porous TiO2 structure in different wt%, (ii) the polymer PEDOT: PSS and small molecule PCBM F.P cavities with different thicknesses were produced, as the thicknesses correspond to different color bands, and (iii) combine the F.P. cavity and rGO-TiO2 to produce a FTO/TiO2-rGO/Dye/Ag/F.P./Ag DSSC. Scanning electron microscope (SEM) images showed that 5 wt% rGO offered the best sheet nano-structure, and this increased the efficiency of DSSC by 28.1% when measured by power conversion efficiency (PCE). The color output advantages of F.P. cavity using PCBM and PEDOT materials are red and blue, respectively. The devices with PEDOT: PSS and PCBM saw a 9 and 12.5% gain compare to DSSC without F.P. cavity. However, two structures of TiO2 doped 5 wt% rGO and colorful PCBM F.P. cavity can increase the efficiency of DSSC by 44.1%. Display omitted •DSSC can produce economical and large-area color solar cells through the solution process.•The porous TiO2 was doped with rGO to improve DSSC efficiency.•Color selection is thickness variation using organic F.P. cavity for colorful DSSC.•Color output advantages of F.P. cavity using PCBM and PEDOT are red and blue, respectively.