Orthorhombic crystal system

Crystal (programming language)

Triiodide

Materials science

Crystal structure

Atomic physics

Single crystal

Computer science

Perovskite (structure)

Inorganic chemistry

Iodide

Physical chemistry

Physics

Exciton

Dielectric

Tetragonal crystal system

Condensed matter physics

Binding energy

Dye-sensitized solar cell

Crystallography

Chemistry

Programming language

Electrode

Electrolyte

Optoelectronics

The Journal of Physical Chemistry Letters

We have accurately determined the exciton binding energy and reduced mass of single crystals of methylammonium lead tri-iodide using magneto-reflectivity at very high magnetic fields. The single crystal has excellent optical properties with a narrow line width of $\sim 3$meV for the excitonic transitions and a 2s transition which is clearly visible even at zero magnetic field. The exciton binding energy of $16 \pm 2$meV in the low temperature orthorhombic phase is almost identical to the value found in polycrystalline samples, crucially ruling out any possibility that the exciton binding energy depends on the grain size. In the room temperature tetragonal phase, an upper limit for the exciton binding energy of $12 \pm 4$ meV is estimated from the evolution of 1s-2s splitting at high magnetic field.

Unraveling the Exciton Binding Energy and the Dielectric Constant in Single-Crystal Methylammonium Lead Triiodide Perovskite