Home Publications Research Grants Inventions & Patents Awards Additional Research Activities Faculties & Institutions Research Areas

Project J – Solution Processed Ferroelectrics in Photovoltaic Devices

---

• Overview

   

• Publications

  (10)

Description / Outline

Organic-inorganic metal-halide perovskites have revolutionized the field of solution processed photovoltaics within the last few years, whereas ferroelectric titanate-based perovskites are the most widely used piezoelectric materials. Piezoelectric response, however, was also observed from solution processed metal-halides, and recently the effect was optimized in a novel compound organic- inorganic perovskite with the composition trimethylchloromethyl ammonium trichloromanganese(II) [TMCM-MnCl₃], which exhibits a piezoelectric coefficient of 185 pC/N that outperforms some lead-free titanates (BaTiO₃ with [001] poling for instance exhibits a value of 105 pC/N). Merging ferroelectrics with photovoltaics has opened interesting and useful aspects: While in conventional semiconductor photovoltaic devices, photoexcited electrons and holes are separated by built-in electric fields from p-n junctions or heterojunctions, in ferroelectric materials internal electric fields due to ferromagnetic domain walls can drive the photoexited carriers. As a consequence, in a traditional semiconductor the maximum open circuit voltage is given by the band gap of the semiconductor, whereas in ferroelectric photovoltaic devices the possibility to achieve above-bandgap voltages have been discussed. A severe disadvantage of the oxide based ferroelectric materials for photovoltaics has been that their band gap energies are too high to efficiently harvest the sun’s spectrum, whereas specially designed low band gap oxide perovskites exhibited relatively good performance only in a multilayer stacked architecture.

Faculty/Institution

Contacts