Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization

Abstract

Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D−π−A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.3% under one sun (AM1.5 G). The co-sensitization strategy was further applied on this blue organic dye together with a red D−π−A dye (D35). The successful co-sensitization outperformed a panchromatic light absorption and improved the photocurrent density; this in addition to the open-circuit potential result in an efficiency of 8.7%. The extended absorption of the sensitization and the slower recombination reaction between the blue dye and TiO 2 surface inhibited by the additional red sensitizer could be the two main reasons for the higher performance. In conclusion, from the results, the highly efficient cobalt-based DSSCs could be achieved with the co-sensitization between red and blue D−π−A organic dyes with a proper design, which showed us the possibility of applying this strategy for future high-performance solar cells.

A small electron donor in cobalt complex electrolyte significantly improves efficiency in dye-sensitized solar cells

“…To overcome this, we further utilized a recently developed co-sensitized system (D35: Dyenamo blue=4:3) as the sensitized films, which effectively broadens the absorption spectrum and has an absorption edge at ∼760 nm (ref. 30). As expected, the photocurrent of the co-sensitized system increased significantly (Fig.…”

First Report of Chenodeoxycholic Acid–Substituted Dyes Improving the Dye Monolayer Quality in Dye‐Sensitized Solar Cells

“…This design was chosen to improve the distribution of dyes and additives in the SAM and reduce the total number of molecules anchored on the TiO 2 surface, with the intention of achieving an overall higher power conversion efficiency (PCE) and increased V OC . Recently, triarylamine‐based sensitizers have achieved outstanding results in DSSCs, using novel cobalt and copper electrolytes . Hence, this popular dye class became the foundation of the study.…”

Role of co-sensitization in dye-sensitized and quantum dot-sensitized solar cells

“…So far, this is the best reported efficiency in DSSC category through co-sensitization method. When a blue region harvesting dye with diketopyrrolopyrrole moiety is co-sensitized with a red dye in the presence of cobalt redox electrolyte, about 8.7% efficiency was achieved [77]. Compared with the traditionally used cobalt based bipyridyl electrolyte [Co(bpy) 3 ] 2+/3+ , hemicage structured cobalt electrolyte [Co(ttb)] 2+/3+ produced stable solar cells with moderate efficiency through co-sensitization [57].…”