US EPA

4788146 

Journal Article 

Improved molecular architecture of D-pi-A carbazole dyes: 9% PCE with a cobalt redox shuttle in dye sensitized solar cells 

Soni, SS; Fadadu, KB; Vaghasiya, JV; Solanki, BG; Sonigara, KK; Singh, A; Das, D; Iyer, PK 

2015 

3 

43 

21664-21671 

10.1039/c5ta06548h 

WOS:000364020400031 

Two new D-pi-A dyes (SK2 & SK3) based on carbazole, and vinylene-phenylene (r-bridge) with rhodanine3-acetic acid and cyanoacrylic acid as electron withdrawing-injecting as well as anchoring groups were designed and synthesised under conditions that were free from precious metakcatalysts and well characterized for dye-sensitized solar cell (DSSC) applications. A high power conversion efficiency (PCE) of 9% (AM 1.5 G, 100 mW cm(-2)) has been achieved using cyanoacrylic acid as an acceptor in D-r-A carbazoIe dye (SK3) with a cobaIt based redox shutte, whiEe a PCE of 7.1% was exhibited in triiodide based redox mediators. A short-circuit current density, Js, of -18.2 mA cm(-2), an open-circuit voItage, 1/0, of -725 mV, and a fill factor, FE of similar to 67% have been afforded by the SK3 based DSSC incorporating the Co2+/Co3+ eIectrolyte as the one-electron redox mediator. In contrast, SK2 dye based DSSCs with a cobaIt based redox mediator have shown a J(SC) mA cm(-2), a V mV, and a FE 48%, yielding a PCE of 2.4%. The devices based on SK3 showed outstanding stabdity performance without significant degradation even after 1000 h of thumination under standard conditions in the Co2Co3+ electrolyte.