Exciton spin dynamics in chiral layered perovskites: an ultrafast spectroscopy study on methylbenzylamine lead iodide (R- and S- MBA2PbI4)
Maria C. Gelvez-Rueda a, Zimu Wei b, Ferdinand C. Grozema b, Bruno Ehrler a
a AMOLF, Amsterdam, Netherlands, Netherlands
b Delft University of Technology, The Netherlands, Julianalaan, 136, Delft, Netherlands
International Conference on Hybrid and Organic Photovoltaics
Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
València, Spain, 2022 May 19th - 25th
Organizers: Pablo Docampo, Eva Unger and Elizabeth Gibson
Poster, Maria C. Gelvez-Rueda, 294
Publication date: 20th April 2022

Spintronics is one of the most important emerging areas in digital technology to develop high-speed, low-power and high-density quantum devices.1 In spintronics, the spin degree of freedom of electrons is exploited explicitly, next to the charge. A key challenge for the field is the development of new semiconductor materials that absorb and emit circularly polarized light with a specific handedness (left-S or right-R) and generate electronic charges with a specific spin state (up or down spin-polarized currents) without requiring strong external magnetic fields.1

Chiral organic-inorganic perovskites are promising materials that are gaining attention in the field of spintronics as studies have reported considerable degrees of cicularly polarized (CP) photoluminescence without magnetic fields (~10% CP-PL) and spin-polarizations of ~86% by mc-AFM.2–4 These results overshadow tradional materials in the field of spintronics like inorganic semiconductors with large spin-orbit interactions (in which a 10% CP PL is achieved at magnetic fields B>5 tesla) and chiral organic chromophores (in which spin-polarizations of ~30% are measured by mc-AFM).2–4 Moreover, it is outstanding that chiral organic-inorganic perovskites exhibit preferential absorption of CP light depending on the handedness of the organic molecule in electronic transitions associated to the inorganic components.2–4   The mechanisms that explain these "chirality transfer" to the inorganic transitions are unknown.2–4  

In this work, we  aim to reveal the mechanisms that allow "chirality transfer" and exciton spin dynamics in chiral perovskites by a combination of in-depth structural characterization (spin-orbit coupling and chirality) and spectrocopy techniques such as circular dichroism and ultrafast CP transient-absorption (TA) spectroscopy. For this, we have synthesized a series of chiral hybrid perovskites using methylbenzylammine (MBA) and naphtylethylamine (NEA) as chiral chromophores, which crystalize in layered two-dimensional and one-dimensional (1D) structures. We report the spin-dynamics of the series of 2D materials,  rac-, R- and S-MBA2PbI4 on picosecond time scale after excitation and probing with CP light.

We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info