Optical absorption and photoluminescence spectroscopy

In this chapter, we summarize the optical absorption and photoluminescence (PL) spectroscopy of metal-halide perovskite semiconductors that are substantially important to understand their behavior in optoelectronic devices and estimate their performance limits. First, we introduce the most common methods to measure the optical absorption of perovskite materials and their limitations followed by the common methods of extracting optical bandgap. Then, we discuss the near bandgap states, the process of light absorption and exciton generation in metal-halide perovskites as well as tuning the optical bandgap of them via chemical modifications. Second, we explain the PL spectroscopy of perovskites and the process involved in it alongside the main extracted parameters including diffusion lengths and carrier lifetime. We also discuss the concept of photon recycling in halide perovskite as well as the exciton binding energy and excitonic peaks in PL. Furthermore, we show effective strategies to tune and stabilize the PL in metal-halide perovskite as well as the impact of crystallinity and charge extraction layers on the PL. Finally, we show the temperature dependency of PL in metal-halide perovskites.