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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Focus Session: Ultrafast Processes in Organic Semiconductors and Perovskites II (joint session O/CPP)

CPP 46.1: Topical Talk

Thursday, March 21, 2024, 15:00–15:30, MA 004

Time-resolved chiroptical probes to track spin & light polarization in solution-processable semiconductors — •Sascha Feldmann — Harvard University, Cambridge, MA, USA

Chiral solution-processable semiconductors based, for example, on small molecules, polymers or halide perovskites offer an exciting new avenue to simultaneously control charge, spin and light using a single material. This could enable efficient spin-optoelectronic devices ranging from displays and holography to detectors, and even applications in quantum information technology.[1] In this talk, I will give an overview of our recent efforts to understand the underlying mechanisms by developing novel time-resolved chiroptical spectroscopy techniques.

By pushing broadband circular dichroism to diffraction-limited spatial and 15 fs time resolution, we create a spin cinematography technique to witness the ultrafast formation of spin domains in halide perovskite films due to local symmetry breaking and spin-momentum locking.[2] In terms of circularly polarized photoluminescence (CPL), I will first explain the fundamentals and artifacts involved in measuring CPL reliably and introduce an open-access methodology and code to do so [3]. I will conclude by showing our most recent development of a transient broadband full Stokes vector polarimetry with unprecedented time and polarization resolution to track the emergence of chiral light emission [to be submitted].

[1] Nature Reviews Materials 8, 365 (2023)

[2] Nature Materials 22, 977 (2023)

[3] Advanced Materials 44, 2302279 (2023)

Keywords: chirality; circularly polarized light; optoelectronics; halide perovskites; small molecules