Electron Beam Sensitivity in Perovskite Nanocrystals as Compared to Bulk Perovskites

Perovskite materials has been very well studied a lot in the past 10 years due to its outstanding optoelectronic properties leading to various applications such as LED, Photovoltaics etc. But characterization of halide perovskite materials have been very difficult due to their air, water, laser and electron beam sensitivity. The quantitative sensitivity to these external factors depend on both physical form of the crystals as well as synthesis process. In this work, the affects of size has been studied on the electron beam sensitivity of halide perovskite materials. Same composition has been synthesized in both bulk and nanocrystal (quantum dots) forms and their degradation to electron beam has been measured and analysed. Negative spherial abberation Transmission Electron Microscopy (TEM) with calculated dose and dose rates have been used to compare the change in electron diffraction of the samples, thereby giving a quantitative difference between beam damage in both the types. The differences have been correlated to surface effects and presence of surface ligands in the lower dimension crystal.