We review the application of impedance spectroscopy in dye-sensitized solar cells, quantum dot-sensitized solar cells and organic bulk heterojunction solar cells. We emphasize the interpretation of the impedance parameters for determining the internal features of the device, concerning the carrier distribution, materials properties such as the density of states and/or doping of the semiconducto...

In recent years, since the introduction of bulk heterojunction concept in an organic solar cell, the efficiency is increased to ∼6%. The benefits of bulk heterojunction (BHJ) organic solar cells are drawing interest for applications in next-generation solar cells. In this study, we analyze the optimal top electrode for practical polymer solar cells (PSC) fabrication by utilizing the optical pro...

Bodipy-based polymers, which possess a high absorption coefficient with a bandgap of approximately 1.6 eV, have been used as electron donor in solution-processed bulk heterojunction (BHJ) solar cells containing PCBM as acceptor. A power conversion efficiency (PCE) of approximately 2% has been achieved with V(oc) of approximately 0.8 eV and J(sc) of approximately 4.8 mA cm(-2).

Vertical arrays of ZnO nanowires can decouple light absorption from carrier collection in PbS quantum dot solar cells and increase power conversion efficiencies by 35%. The resulting ordered bulk heterojunction devices achieve short-circuit current densities in excess of 20 mA cm(-2) and efficiencies of up to 4.9%.

The importance of symmetry breaking was investigated in bulk heterojunction solar cells with a conventional device structure. Artificial symmetry breaking was built up by introducing a titanium suboxide. With sufficient symmetry breaking, the influence of the cathode work-function can be diminished, thereby extracting the same level of open circuit voltage regardless of metal work-function.

A series of unsymmetrical π-conjugated small molecules have been constructed from meso-alkyl substituted porphyrins as the central unit and 3-ethylrhodanine as the terminal group. Using PC71BM as an acceptor, and these small molecules as electron donors in solution-processed bulk-heterojunction solar cells, a high power conversion efficiency of 6.49% has been achieved.