A comparison of example MAPbBr3 optical properties (refractive index, n, and extinction coefficient, k) reported in the literature is shown in Figure . The optical dispersions compared in Figure represent the optical properties of MAPbBr3 grown using different antisolvent, hydrothermal, and ITC The magnitude of the Δn and Δk in Figure is unexpected assuming controlled MAPbBr3 growth processing conditions and appropriate post-growth handling procedures. However, changes due to processing dependencies and surface or bulk material degradation have been shown to change the chemical composition and crystalline structure of MAPbX3 that directly impact the associated optical properties. Process-induced effects are known to generate lattice defects and dopant impurities while material degradation generally occurs due to unprotected, prolonged ambient air and moisture exposure under variable temperature fluctuation. Defects and impurities within the crystalline lattice (such as lead or halide vacancies or interstitials) and surface degradation (such as oxidation) also affect the resulting optical properties of MAPbBr3 primarily due to changes to the band gap (chemical composition), electron-hole pair recombination dynamics, and/or associated absorption/emission behavior. Additionally, as mentioned above, inaccurate modeling assumptions and the resulting robustness of the optical dispersion data analysis can potentially contribute to variability in the derived n and k (discussed in Section 3.3).