December 1 - 6, 2024
Boston, Massachusetts
Symposium Supporters
2024 MRS Fall Meeting & Exhibit
QT01.02.02

Highly Selective Room-Temperature Spin-Polarized Light-Emitting Diodes Enabled with Chiral Two-Dimensional Perovskties

When and Where

Dec 2, 2024
2:00pm - 2:15pm
Sheraton, Fifth Floor, Jamaica Pond

Presenter(s)

Co-Author(s)

Gyumin Jang1,Chan Uk Lee1,Wooyong Jeong1,Jaehyun Son1,Jeong Hyun Park1,Jooho Moon1

Yonsei University1

Abstract

Gyumin Jang1,Chan Uk Lee1,Wooyong Jeong1,Jaehyun Son1,Jeong Hyun Park1,Jooho Moon1

Yonsei University1
Circularly polarized light (CPL) is an essential light source with a broad range of potential applications, including magnetic recording, three-dimensional displays, and information processing. In this work, we introduce core−shell heterostructured perovskite quantum dots (QDs) for room-temperature spin-polarized light-emitting diodes (spin-LEDs). Specifically, 2-dimensional (2D) chiral organic−inorganic hybrid perovskite shell was deposited onto the achiral 3D inorganic CsPbBr<sub>3</sub> perovskite core. It is demonstrated that (<i>R</i>)- and (<i>S</i>)-1-(2-(naphthyl)ethylamine) chiral cations can enhance the degree of spin polarization due to their robust chiroptical properties. Owing to the chiral-induced spin selectivity (CISS) effect, the spin state of the injected charge carriers is biased when they are transmitted through the 2D chiral shell. Such spin-controlled carriers then undergo radiative recombination within the CsPbBr<sub>3</sub> core, resulting in the CPL emission. The spin-LEDs fabricated with core−shell QDs attained a maximum external quantum efficiency (EQE) of 5.47% and exhibited circularly polarized electroluminescence with an outstanding polarization degree (<i>P<sub>CP-EL</sub></i>) for both left- and right-handed 2D chiral perovskites at room temperature.<br/> Furthermore, blue spin-LEDs are demonstrated for the first time by inserting (<i>R</i>)- and (<i>S</i>)-2-fluoro-methylbenzylamine (<i>R</i>/<i>S</i>-2F-MBA) chiral cation into the surface of Br/Cl-mixed halide perovskite films. It was found that small ionic radii of bromide and chloride ions enable deeper penetration of ammonium functional groups inside chiral cations, enhancing circular dichroism of 2D chiral perovskites by ~4 fold. Due to the increased chiroptical properties as well as spin selectivity, resulting blue spin-LEDs exhibited remarkable circularly polarized electroluminescence dissymmetry factor. Also, halide vacancies inside perovskite films were effectively passivated because of a high polarity of <i>R</i>/<i>S</i>-2F-MBA chiral cations, thereby achieving a notable EQE.

Keywords

organometallic | spin

Symposium Organizers

Volker Blum, Duke University
Sascha Feldmann, Harvard University
Paulina Plochocka, CNRS
Tze Chien Sum, Nanyang Technological University

Symposium Support

Silver
Light Conversion
FHI-aims - First-Principles Materials Simulations
Quantum Design

Session Chairs

Volker Blum
Paulina Plochocka
Shuxia Tao

In this Session