Economy and colors based on solution-process rGO-TiO2 dye-sensitized solar cells modulated with organic Fabry-Perot cavity for indoor photovoltaic

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%.