Unveiling defects and charge carrier dynamics in 3D and 2D perovskites using high-sensitivity spectroscopic techniques

Non-radiative recombination of electronic charge carriers via defect states in the bulk and at semiconductor interfaces significantly limits the performance of optoelectronic devices, including solar cells, photoelectrochemical cells, and light-emitting diodes. In this talk, I will demonstrate how a combination of high-sensitivity, contactless techniques—such as time-resolved and light-modulated surface photovoltage (SPV) and Constant Final State Yield Spectroscopy (CFSYS)—can directly probe the energetic location of defects in various semiconductor families. These include 3D and 2D halide perovskites (HaPs) and emerging lead-free double perovskites. Additionally, I will demonstrate how time-resolved SPV measurements, spanning timescales from nanoseconds to seconds, provide valuable insights into fundamental charge carrier dynamics at buried interfaces of optoelectronic materials. These insights range from the dissociation and recombination of excitons in emerging HaPs to charge transfer kinetics and trapping/de-trapping mechanisms at interfaces between charge-selective layers and HaPs.