Atypical organic dyes used as sensitizers for efficient dye-sensitized solar cells

Since their invention, dye-sensitized solar cells (DSSCs) have received enormous research attention from scientists with different background due to the possibility of low-cost production and fabrication on flexible substrates. One of the most important components in DSSCs is the sensitizing dye, including metal-complexes and metal-free organic dyes. The donor-π bridge-acceptor (D-π-A) structure is the mainstream in the design of organic sensitizers because it facilitates efficient charge-transfer toward the TiO2 upon excitation. However, some sensitizers that do not follow this structure, or have some modification upon this structure, also present good efficiency when applied in DSSC devices. This review summarizes these atypical dyes in order to inspire more diverse designs toward highly efficient DSSCs. © 2016, Higher Education Press and Springer-Verlag Berlin Heidelberg.