Presentation description

Two-dimensional (2D) perovskites are a promising material for the next generation of photovoltaics and LEDs because of their stability, tunable bandgaps, and solution processability, allowing for facile synthesis of thin films. Previous studies have successfully codified how the chemical structure of the organic spacer cations influences their optical properties, but it is still unknown how cations mixing impacts optical properties. The goal of this project is to investigate the design rules underlying whether two cations will blend or phase separate when mixed. We hypothesize that blending different organic spacer cations may induce octahedral distortions, which impact the perovskite bandgap. To do this, we have identified several common organic spacer cations that show promise in applications, and blended them with the F3C-phenyl-methy ammonium (F3C-PMA) cation, which exhibits a larger octahedral distortion than other common organic cations. This process is expedited through the use of a high-throughput robot which allows for the autonomous preparation of these blended thin films. Here we report several 2D organic spacer cation blends that show high quality, single-phase films upon using X-ray diffraction (XRD). Furthermore, we use photoluminescence and absorption spectroscopy to confirm a shift in the bandgap, indicating a new mixed cation material.