Four novel naphthalimide-based dyes (D-1, D-2, D-3 and D-4) were synthesized and utilized as sensitizers in dye-sensitized solar cells (DSCs), in which the triphenylamine (TPA) or indoline groups, naphthalimide unit and carboxylic group were functionalized as electron donor, acceptor and anchoring group, respectively. The naphthalimide unit was employed as the π-conjugation ring and electron acceptor for effectively realizing intramolecular ...