Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been mostly used as a counter electrode to give a high performance of dye-sensitized solar cell (DSSC). Recently, PEDOT doped by carrageenan, namely PEDOT:Carrageenan, was introduced as a new material to be applied on DSSC as an electrolyte. PEDOT:Carrageenan has a similar synthesis process as PEDOT:PSS, owing to their similar ester sulphate (-SO₃H) groups in both PSS and carrageenan. This review provides an overview of the different roles between PEDOT:PSS as a counter electrode and PEDOT:Carrageenan as an electrolyte for DSSC applications. The synthesis process and characteristics of PEDOT:PSS and PEDOT:Carrageenan were also described in this review. In conclusion, we found that the primary role of PEDOT:PSS as a counter electrode is to transfer electrons back to cell and accelerate redox reaction with its superior electrical conductivity and high electrocatalytic activity. PEDOT:Carrageenan as an electrolyte has not shown the main role for regenerating the dye sensitized at the oxidized state, probably due to its low ionic conductivity. Therefore, PEDOT:Carrageenan still obtained a low performance of DSSC. Additionally, the future perspective and challenges of using PEDOT:Carrageenan as both electrolyte and counter electrode are described in detail.

Recently, hybrid solar cell, which is a combination of organic and inorganic material, has been developed to produce better performance especially in power conversion efficiency of solar cell. Organic material based on conjugated polymer such as Poly(3-hexylthiophene) (P3HT) attracted much attention because P3HT shows the highest hole mobility among the series of Poly(3-alkylthiophene). On the other hand, it is well known that ZnO nanoparticles are an inorganic material with high electron mobility that can be acted as electron acceptor to dissociate excitons formed in organic material. The existence of ZnO nanoparticles in active layer of solar cell will lead to dissociation of excitons in P3HT via rapid electron transfer to ZnO. To understand the mechanism of charge carrier transport in blend of P3HT and ZnO nanoparticles, we have been conducted an experiment using muon spin relaxation (µSR) at low temperature of 10 K with variation of longitudinal field from 2 to 395 mT. We also investigated the effect of light irradiation to the charge carrier transport in blend of P3HT and ZnO nanoparticles. Without light irradiation, it is clearly observed that depolarization rate (λ) was proportional to linier field of H^-0.5, indicating one-dimensional intra-chain transport of charge carrier. With light irradiation, it is found that asymmetry data changed slightly indicating the trace of any changing of charge carrier transport to increase in the amount of exciton in samples causing by light irradiation.

Photoanode of dye sensitized solar cell (DSSC) plays an important role as electron transport media to accept photogenerated electron from excited state of dye. There are several physical properties that are required from photoanode of DSSC. It should be highly transparent, have large surface area, has a conduction band lower than LUMO of dye molecule, has high charge carrier mobility and finally has a good stability in redox electrolyte process. In this work, DSSC with structure FTO/ZnO nanorod/TiO₂ mesoporous/Ru-dye/gel electrolyte/ Pt/FTO has been fabricated. In order to modified the structures of photoanode, ZnO nanorod was grown on aluminium doped ZnO seed layer by variation concentration of Al (0 wt%, 0.5 wt% and 1.0 wt%). Zinc nitrate hexahydrate and hexamethylenetetramine used as raw materials for ZnO nanorod growth solution and deposited by self-assembly methods on FTO/Al doped ZnO seed layer. It is then followed by deposition of titania (TiO₂) paste by screen printing methods. DSSC parameters i.e. ideally factor (n), series resistance (R_S ), and shunt resistance (R_SH ) was derived from current density-voltage (I-V) curve using the simplify equation of ideal diode model. The influences of ZnO photoanode structures to the solar cell performance will be completely discussed.

Dye-sensitized solar cells (DSSC) are solar cells that has a great potential to be applied as renewable energy conversion. The major advantages of DSSC are the ease of fabrication process and low cost of production. Despite of these advantages, the efficiency of DSSC for converting light into electricity is still low. It is due to charge recombination in DSSC which limits the photoanode performance. Numerous efforts has been carried out to increase the efficiency of DSSC, one of which is by adding reduced graphene oxide (rGO) to titanium oxide (TiO₂) to obtain TiO₂-rGO nanocomposite. In this study, the synthesis of TiO₂-rGO nanocomposites was carried out with concentration of rGO are 0.6, 0.8, and 1.0 wt% to amount of TiO₂. We have done some characterizations to confirm the result of synthesized TiO₂-rGO. UV-Vis measurement shows the addition of rGO has widened the absorption up to 400 nm. The FT-IR spectrum confirms that the rGO peaks appears at wavelength of 1400, 1600, dan 1700 cm^-1 which exhibited the vibration C-O, C=C, and C=O stretching from COOH groups, respectively. The highest efficiency of DSSC with photoanode TiO₂-rGO nanocomposite is 0.09% which was obtained from 0.8 wt% of rGO.

Poly(3,4-ethylenedioxythiophene) (PEDOT) with a dopant of polystyrene sulfonate (PSS), namely PEDOT:PSS, has been mostly used as counter electrode to give a high performance of dye-sensitized solar cells (DSSCs). Recently, PEDOT doped by carrageenan (PEDOT:Carrageenan) was introduced as a new material to be applied on DSSC as electrolyte. PEDOT:Carrageenan has a similar synthesis process as PEDOT:PSS owing to their similar ester sulphate (-SO3H) groups in both PSS and carrageenan. This review provides an overview of the different roles between PEDOT:PSS as counter electrode and PEDOT:Carrageenan as electrolyte for DSSC applications. The synthesis process and characteristics of PEDOT:PSS and PEDOT:Carrageenan were also described in this review. In conclusion, we found that PEDOT:PSS as counter electrode has the main roles of transferring electrons from the external circuit and accelerating the reduction reaction of redox coupled with its high electrical conductivity and high electrocatalytic activity. As electrolyte, PEDOT:Carrageenan has not shown the main role as an electron transfer from counter electrode to regenerate the dye-sensitized at the oxidized state due to its low ionic conductivity. Therefore, PEDOT:Carrageenan still obtained a low performance of DSSCs. Additionally, the future perspective and challenges of using PEDOT:Carrageenan as both electrolyte and counter electrode are described in detail.