Mechanical properties of the ferroelectric metal-free perovskite [MDABCO](NH₄)I₃

The metal-free hybrid organic–inorganic perovskite [MDABCO](NH₄)I₃ (with MDABCO = N-methyl-1,4-diazabicyclo[2.2.2]octane) was recently discovered to exhibit an excellent ferroelectric performance, challenging established ceramic ferroelectrics. We here probe the mechanical properties of [MDABCO](NH₄)I₃ by combining high pressure single crystal X-ray diffraction and nanoindentation, underlining the exceptional role and opportunities that come with the use of sustainable, metal-free perovskite ferroelectrics.