Rüdiger Sens

Enhancing Thermal Stability and Lifetime of Solid-State Dye-Sensitized Solar Cells via Molecular Engineering of the Hole-Transporting Material Spiro-OMeTAD

Thermal stability of hybrid solar cells containing spiro-OMeTAD as hole-transporting layer is investigated. It is demonstrated that fully symmetrical spiro-OMeTAD is prone to crystallization, and growth of large crystalline domains in the hole-transporting layer is one of the causes of solar cell degradation at elevated temperatures, as crystallization of the material inside the pores or on the interface affects the contact between the absorber and the hole transport. Suppression of the crystal growth in the hole-transporting layer is demonstrated to be a viable tactic to achieve a significant increase in the solar cell resistance to thermal stress and improve the overall lifetime of the device. Findings described in this publication could be applicable to hybrid solar cell research as a number of well-performing architectures rely heavily upon doped spiro-OMeTAD as hole-transporting material.

DESIGN, SYNTHESIS, AND EVALUATION OF A DYE LIBRARY : GLASS-FORMING AND SOLID-STATE LUMINESCENT MEROCYANINES FOR FUNCTIONAL MATERIALS

A highly efficient multicomponent reaction based on the little-known formylating agent dimethylformamide in acetic anhydride led to a multitude of dyes of the indoline (1) and of the thiazole type (2), whose systematic evaluation revealed desired and surprising solid-state properties.

Parallel Bulk‐Heterojunction Solar Cell by Electrostatically Driven Phase Separation

Thermal co-evaporation of C(60) fullerene and two merocyanine dyes affords bulk heterojunction solar cells with improved short-circuit currents and power conversion efficiencies in comparison with the respective single donor cells. These results are rationalized by the formation of three distinct subphases driven by differences in molecular shape and electrostatic interactions.