High-yield TiO2 submicron sphere/nanoparticle-blended scattering layer for efficient and scalable dye-sensitized solar cells

Scattering layer in dye-sensitized solar cell (DSSC) has a proven potential to enhance the photoconversion efficiency (PCE) of DSSC by increasing light harvesting ability. Scattering layer composed of submicron sized particles which scatter light effectively; however, large size aggregated particles possess poor surface area and create voids between particles leading to lose interconnectivity, and consequently low dye adsorption and higher recombination with electrolyte. Several scattering structures are developed to overcome these issues, it is found that in majority previous reports very low precursor concentration is used and longer reaction time is given to attain highly homogenous and porous scattering particles which ultimately produced very small yield of TiO 2 . This low yield makes these processes limited to commercialize. Therefore, in current study, a facile approach has been used to prepare high-yield TiO 2 submicron spheres (SMS) as a scattering particle and blended with nanoparticles (NPs) of TiO 2 to overcome voids and increase surface area. Diffuse reflectance and incident-photon-to-current-conversion-efficiency (IPCE) investigations have demonstrated that prepared SMS/NP scattering layer is effective to broadened light harvesting spectrum. Moreover, electrochemical impedance spectroscopy (EIS) revealed that NPs incorporation in SMS significantly increased electron lifetime from 3.29 × 10 −1 s for (0 wt% NPs) to 3.95 × 10 −1 s for (20 wt% NPs); consequently, PCE increased by ~ 11%, ~ 13%, and ~ 23% as compared to 0 wt% NPs, Dyesol-S (commercial scattering paste) and without scattering layer-based devices respectively. Results indicated that high yield with small reaction time of TiO 2 submicron spheres have real potential to scale-up for the development of DSSC.