title: Dyes and Redox Couples with Matched Energy Levels: Elimination of the Dye-Regeneration Energy Loss in Dye-Sensitized Solar Cells.
abstract: In dye-sensitized solar cells (DSSCs), a significant dye-regeneration force (ΔG(reg)(0)≥0.5 eV) is usually required for effective dye regeneration, which results in a major energy loss and limits the energy-conversion efficiency of state-of-art DSSCs. We demonstrate that when dye molecules and redox couples that possess similar conjugated ligands are used, efficient dye regeneration occurs with zero or close-to-zero driving force. By using Ru(dcbpy)(bpy)2(2+) as the dye and Ru(bpy)2(MeIm)2(3+//2+) as the redox couple, a short-circuit current (J(sc)) of 4 mA cm(-2) and an open-circuit voltage (V(oc)) of 0.9 V were obtained with a ΔG(reg)(0) of 0.07 eV. The same was observed for the N3 dye and Ru(bpy)2(SCN)2(1+/0) (ΔG(reg)(0)=0.0 eV), which produced an J(sc) of 2.5 mA cm(-2) and V(oc) of 0.6 V. Charge recombination occurs at pinholes, limiting the performance of the cells. This proof-of-concept study demonstrates that high V(oc) values can be attained by significantly curtailing the dye-regeneration force.
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Dianlu
authors: D
authors: Jiang
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Narek
authors: N
authors: Darabedian
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Sevak
authors: S
authors: Ghazarian
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.|College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, Henan, China.
authors: Yuanqiang
authors: Y
authors: Hao
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Maxim
authors: M
authors: Zhgamadze
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Natalie
authors: N
authors: Majaryan
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
authors: Rujuan
authors: R
authors: Shen
authors: Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA. Fzhou@calstatela.edu.
authors: Feimeng
authors: F
authors: Zhou
keywords: dye regeneration; dye-sensitized solar cells; electrochemistry; energy transfer; energy-level matching