Correlation of Band-gap and Exiton Binding Energies in Metal-Halide Perovskites

Metal-halide perovskites are a class of semi-conductors that have application in solar cells, LEDs, and potentially spintronics/quantum computing. One of their main appeals is the incredibly vast pool of compositions for both the crystal layer and the organic layer, allowing for tuning of the band-gap (E_g) and exciton binding energies (E_b). Using absorption and electro-absorption experiments to measure E_g and E_b, we have found a linear relationship between the E_g and E_b. Our findings deviate from the predictions made by previous mathematical models.