Synthesis and properties of polyurea/malonamide dendritic co-adsorbents for dye-sensitized solar cells

A series polyurea/malonamide dendron (G0.5-G2.5) containing C10 alkyl chain located at the peripheral were prepared as dendritic building blocks via alternative addition and ring opening reactions. Afterward, G0.5, G1.5 and G2.5 consisting of azetidine-2,4-dione functional group was selected and reacted with 6-aminohexanoic to generate the corresponding acid anchor containing dendritic co-adsorbents (GA₆-0.5, GA₆-1.5 and GA₆-2.5). The dye-sensitized solar cells (DSSCs) were then fabricated using phenothiazine-based dyes (HL5) as sensitizer with different generations and concentrations of dendritic co-adsorbents to explore the effect on cell performances and interfacial charge properties. Upon addition 0.3 mM of GA₆-2.5 co-adsorbent, the best efficiency was 6.66 ± 0.07%, with a current density (Jsc) of 12.88 ± 0.11 mA cm⁻², an open circuit voltage (Voc) of 0.72 ± 0.00 V and a fill factor of 0.72 ± 0.00. This cell exhibits superior efficiency than the HL5 dye only (PCE = 5.67 ± 0.17%) and slightly higher than the standard 3 mM CDCA co-adsorbent based device (PCE = 6.33 ± 0.04%). In addition, this best efficiency of this cell reached 83% of the N719 standard cell. This study may pave a new way for achieving high-performance with low cost on DSSCs applications.