Influence of spacer and donor groups as tetraphenylethylene or triphenylamine in asymmetric zinc phthalocyanine dyes for dye-sensitized solar cells

•Two new asymmetric Zn (II) phthalocyanine dyes bearing triphenylamine or tetraphenyletyhlene donor groups and carboxylic acid or phenoxy carboxylic acid anchoring groups were synthesized for DSSCs.•Their optical and electrochemical characteristics were investigated.•The photovoltaic properties of single DSSCs were described.•The effect of different donor groups (bearing triphenylamine or tetraphenyletyhlene) on PCE was examined.•The effect of functionalization with two different types of carboxylic groups on PCE was discussed.