Push‐Pull Phenoxazine‐Based Sensitizers for p‐Type DSSCs: Effect of Acceptor Units on Photovoltaic Performance
Kavya S. Keremane, Aurélien Planchat, Yann Pellegrin, Denis Jacquemin, Fabrice Odobel, Airody Vasudeva Adhikari
Abstract
Abstract Finding new efficient p‐type sensitizers for NiO photocathodes is a great challenge for the development of promising low‐cost tandem dye‐sensitized solar cells (DSSCs). Now, the focus of researchers investigating these cells has been to create high‐performance p‐type systems. With this intention, herein, the design and synthesis of six new phenoxazine‐based donor–acceptor (D–A)‐configured organic dyes PO 1–6 was reported, comprising different acceptor moieties specially designed for the sensitization of mesoporous p‐type semiconductor NiO for the construction of p‐type DSSCs (p‐DSSCs). This work includes structural, photophysical, thermal, electrochemical, theoretical, and photoelectrochemical studies of these dyes, including evaluation of their structure‐property relationships. The optical studies revealed that PO 1–6 displayed adequate absorption and emission features in the range of 480–550 and 560–650 nm, respectively, with a bandgap in the order of 2.05–2.40 eV, and their thermodynamic parameters favored an efficient interfacial charge transfer involving NiO. Among the six new dyes, the device based on sensitizer PO 2 carrying electron‐withdrawing 1,3‐diethyl‐2‐thiobarbituric acid achieved the highest power conversion efficiency of 0.031 % (short‐circuit current density=0.89 mA cm −2 , open‐circuit voltage=101 mV, and fill factor=35 %). Conclusively, the study furnishes an understanding of the intricacies involved in the structural modification of phenoxazine‐based sensitizers to further ameliorate the performance of the p‐type DSSCs.