Fig. 1: a) Schematic of the photoluminescence (PL) mechanism for Y3N@C80. S0: ground state; S1: singlet excited state; T1: triplet excited state; ISC: intersystem crossing; rev-ISC: reverse intersystem crossing; F: fluorescence; TADF: thermally activated delayed fluorescence; P: phosphorescence. b) Temperature-dependent PL spectra of Y3N@C80. c) Selected PL spectra of Y3N@C80 at representative temperatures. d) PL of Y3N@C80 under applied magnetic field conditions; the magnetic field can be up to 42 T from 0 T in two directions. e) Phosphorescence spectra of Y3N@C80 under an applied magnetic field in the positive direction. f) Phosphorescence wavelength changes of Y3N@C80 under varied magnetic fields in the positive and negative directions.
Background?
The magnetic field effect (MFE) is a powerful tool for regulating spin polarization, carrier dynamics, and optoelectronic properties. Among them, magneto-photoluminescence (MPL) describes how magnetic fields tune photoluminescence, providing insights into exciton characteristics and enabling applications in advanced optical and quantum devices. Molecular materials with adjustable structures also exhibit MPL by altering singlet–triplet populations, offering opportunities in molecular spintronics. Fullerene-based systems, particularly endohedral metallofullerenes, are promising due to their unique electronic structures and long-lived excited states. In this context, Y₃N@C₈₀ stands out, showing distinct singlet and triplet emissions with exceptionally long triplet lifetimes, making it an excellent model for exploring MPL responses.
What we discover?
This paper reports the discovery of a magneto-photoluminescence response in metallofullerene Y₃N@C₈₀ triggered by the triplet excited state. In experiments, Y₃N@C₈₀ exhibits magnetic field-dependent (0 → ±42 T) phosphorescence emission at 4.2 K. Crucially, with increasing magnetic field, the phosphorescence peaks shift to longer wavelengths owing to the Zeeman effect. Further, a nanoring of [9]CPPH is employed to modulate the magneto-photoluminescence response of Y₃N@C₈₀ through host–guest interaction. The circularly polarized phosphorescence spectra of Y₃N@C₈₀ and Y₃N@C₈₀⊂[9]CPPH are investigated to further reveal their magneto-photoluminescence properties using the technique of field-induced circular polarization (FICPO).
Why is this important?
These results show that metallofullerene Y₃N@C₈₀ with magneto-photoluminescence response has potential applications in spin-related optical devices and quantum technology. Moreover, it can be observed that metallofullerene Y₃N@C₈₀ shows magneto-photoluminescence properties similar to those of quantum dots due to the quantized energy levels. Based on the triplet state in Y₃N@C₈₀, optically addressable molecular spins for quantum information science also can be designed in the future.
Who did the research?
Chaofeng Zheng1,2, Guixian Li3, Jiayi Liang1,2, Lu Yu4, Wang Li1, YiboHan3*, Chunru Wang1, and Taishan Wang5*
(1) Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
(2) University of Chinese Academy of Sciences, Beijing 100049, China
(3) Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
(4) High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
(5) MOE Key Laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, China
Adv. Optical Mater. 2024, 12, 2303334.
https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202303334
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