Tolerant Soft Semiconductors

Soft semiconductors, halide perovskites, double perovskites and rudorffites as well as an image of single crystals and a thin film
Picture: Felix Lang
Illustration of various soft semiconductors: Solution grown single crystals and spin-coated thin films

Modern electronics, sensors, and solar cells are made from crystalline silicon, a semiconductor with a covalent lattice with short lattice constants and strong binding. The material requires high temperatures during fabrication, and the resulting crystal is stable up to high temperatures. However, when damaged, e.g. during mechanical stress or high-energetic radiation, the lattice cannot self-heal. Soft semiconductors rely on weaker binding, large lattice constants, and small atom displacement energies. This allows swift healing of various damage in the semiconductor crystal, avisionary approach enabling novel tolerant electronics.

Sketched above are three examples of halide-based rudorffite, double perovskite, and perovskite structures: AgBiI4, Cs2AgBiBr6, and CH3NH3PbI3, respectively. These material classes follow an A2M+M3+X6, AaMmXx (x = a + 3m), or AM2+X3 structures, with low formation energies and low migration barriers for halide (X), metal (M), and anion (A) species enabling facile preparation and various self-healing mechanisms.

We synthesize novel soft-semiconductors and study the (opto-) electronics properties of prepared thin films and single crystals. In addition to these fundamental studies we develop medical radiation detectors, space photovoltaics and novel electronics