Synthesis and photovoltaic performance of dihydrodibenzoazepine-based sensitizers with additional lateral anchor

• Three novel dihydro-5H-dibenzo[b,f]azepine based dyes with a D–D–π–A system were designed and synthesized.
• Carboxy and hydroxy groups were introduced into the dye molecules as additional lateral anchoring groups.
• The additional lateral anchoring groups influence the photovoltaic performance of the dyes.

Three novel metal-free organic dyes with dihydro-5H-dibenzo[b,f]azepine as a donor and cyanoacrylic acid as an anchoring unit were designed as an innovative linear skeleton of D–D–π–A type of organic dyes. The conversion efficiency of the derived dye-sensitized solar cells is moderate. Among them, the dye with a hydroxy group as an additional anchoring moiety exhibited the highest UV–Vis absorption with a maximum molar extinction coefficient of 24,136 M−1 cm−1 at λmax = 458 nm and the best photovoltaic performance with an overall power conversion efficiency of 4.88%, while the dye with a carboxy group as an additional anchoring moiety exhibited the lowest conversion efficiency (4.52%). The results show that the dye loading on the film and photovoltaic performance of the dyes were influenced by the additional anchoring units.

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