Feng Pan

All Publications

• Twisted Tin-Chloride Perovskite Single-Crystal Heterostructures. Angewandte Chemie (International ed. in English) Cleron, J. L., Chen, C. Y., Pan, F., Saha, S., Marlton, F. P., Stolz, R. M., Li, J., Dionne, J. A., Liu, F., Filip, M. R., Karunadasa, H. I. 2025: e20140

  Abstract

  Self-assembly affords simpler synthetic routes to heterostructures compared with manual layer-by-layer stacking, yet controlling interlayer twist angles in a bulk solid remains an outstanding challenge. We report two new single-crystal heterostructures: (Sn2Cl2)(CYS)2SnCl4 (CYS = +NH3(CH2)2S-; Sn_CYS) and (Sn2Cl2)(SeCYS)2SnCl4 (SeCYS = +NH3(CH2)2Se-; Sn_SeCYS) synthesized in solution, with alternating perovskite and intergrowth layers. Notably, compared to the recently reported lead analog, (Pb2Cl2)(CYS)2PbCl4 (Pb_CYS), the tin heterostructures feature a twist between the perovskite and intergrowth layers. We trace this twist to local distortions at the Sn centers, which change the interfacial lattice-matching requirements compared to those of the Pb analog. Electronic band structure calculations show that the striking differences in the relative energies of perovskite- and intergrowth-derived bands in Sn_CYS and Pb_CYS arise from structural and not compositional differences. The structural anisotropy of Sn_CYS is also reflected in a large in-plane photoluminescence linear anisotropy ratio. Interfacial strain further affords differential incorporation of Pb into the perovskite and intergrowth layers of the Sn heterostructures, resulting in redshifted optical absorption onsets. Thus, we posit that local structural distortions may be exploited to manipulate the twist angle and interfacial strain in bulk heterostructures, providing a new handle for tuning the band alignments of bulk quantum-well electronic structures.

  View details for DOI 10.1002/anie.202520140

  View details for PubMedID 41414937

• Room-temperature valley-selective emission in Si-MoSe2 heterostructures enabled by high-quality-factor chiroptical cavities. Nature communications Pan, F., Li, X., Johnson, A. C., Dhuey, S., Saunders, A., Hu, M. X., Dixon, J. P., Dagli, S., Lau, S. C., Weng, T., Chen, C. Y., Zeng, J. H., Apte, R., Heinz, T. F., Liu, F., Deng, Z. L., Dionne, J. A. 2025

  Abstract

  Transition metal dichalcogenides possess valley pseudospin, enabling coupling between photon spin and electron spin for classical and quantum information processing. However, rapid valley-dephasing processes have impeded the development of scalable, high-performance valleytronic devices operating at room temperature. Here we demonstrate that a chiral resonant metasurface can enable room-temperature valley-selective emission in MoSe2 monolayers independent of excitation polarization. This platform provides circular eigen-polarization states with a high quality factor (Q-factor) and strong chiral near-field enhancement. The fabricated Si chiral metasurfaces exhibit chiroptical resonances with Q-factors up to 450 at visible wavelengths. We reveal degrees of circular polarization (DOP) reaching a record high of 0.5 at room temperature. Our measurements show that the high DOP can be attributed to the significantly increased chiroptical local density of states, which enhances valley-specific radiative transition rates by a factor of ~13. Our work could facilitate the development of ultracompact chiral classical and quantum light sources.

  View details for DOI 10.1038/s41467-025-66502-4

  View details for PubMedID 41318601

• Resonant metasurface-enabled quantum light sources for single-photon emission and entangled photon-pair generation. Nanophotonics (Berlin, Germany) Pan, F., Bordoloi, P., Chen, C. Y., Dionne, J. A. 2025; 14 (23): 3861-3870

  Abstract

  Light encodes information in multiple degrees of freedom (e.g., frequency, amplitude, and phase), enabling high-speed, high-bandwidth communication through fiber optics. Unlike classical light, quantum light (single or entangled photons) can transmit quantum states over long distances without loss of coherence, thereby coherently interconnecting quantum nodes for distributed quantum entanglement. Quantum light sources are critical for developing scalable quantum networks aimed at distributed quantum computing, quantum teleportation, and secure quantum communications. However, existing quantum light sources suffer from limited integrability, insufficient spectral and spatial tunability, and inefficiencies in achieving mass-produced, deterministic, on-demand quantum light generation. These limitations significantly hinder progress toward direct, on-chip integration with quantum processing units and detectors - an essential step toward scalable quantum networks. Resonant metasurfaces that leverage photonic modes - such as Mie resonances, guided-mode resonances, or symmetry-protected bound states in the continuum - offer strong spatial and temporal confinement of electromagnetic fields, characterized by high quality factors and small mode volumes. These metasurfaces greatly enhance linear and nonlinear light-matter interactions, making them ideal for efficient on-chip quantum light generation and manipulation. Here, we describe recent advances in nanoscale quantum light sources and quantum photonic state manipulation enabled by resonant metasurfaces. We also provide an outlook on next-generation miniaturized quantum light sources achievable through materials innovations in quantum emitters, the co-design of resonant metasurfaces, and ultimately, the heterogeneous integration of emerging layered van der Waals materials with resonant metasurfaces.

  View details for DOI 10.1515/nanoph-2025-0196

  View details for PubMedID 41246496

  View details for PubMedCentralID PMC12617726

• Resonant metasurface-enabled quantum light sources for single-photon emission and entangled photon-pair generation NANOPHOTONICS Pan, F., Bordoloi, P., Chen, C., Dionne, J. A. 2025

  View details for DOI 10.1515/nanoph-2025-0196

  View details for Web of Science ID 001570301100001

• Spectroscopy in Nanoscopic Cavities: Models and Recent Experiments. Annual review of physical chemistry Bourgeois, M. R., Pan, F., Anyanwu, C. P., Nixon, A. G., Beutler, E. K., Dionne, J. A., Goldsmith, R. H., Masiello, D. J. 2024; 75 (1): 509-534

  Abstract

  The ability of nanophotonic cavities to confine and store light to nanoscale dimensions has important implications for enhancing molecular, excitonic, phononic, and plasmonic optical responses. Spectroscopic signatures of processes that are ordinarily exceedingly weak such as pure absorption and Raman scattering have been brought to the single-particle limit of detection, while new emergent polaritonic states of optical matter have been realized through coupling material and photonic cavity degrees of freedom across a wide range of experimentally accessible interaction strengths. In this review, we discuss both optical and electron beam spectroscopies of cavity-coupled material systems in weak, strong, and ultrastrong coupling regimes, providing a theoretical basis for understanding the physics inherent to each while highlighting recent experimental advances and exciting future directions.

  View details for DOI 10.1146/annurev-physchem-083122-125525

  View details for PubMedID 38941525

• Solution-phase sample-averaged single-particle spectroscopy of quantum emitters with femtosecond resolution. Nature materials Shi, J., Shen, Y., Pan, F., Sun, W., Mangu, A., Shi, C., McKeown-Green, A., Moradifar, P., Bawendi, M. G., Moerner, W. E., Dionne, J. A., Liu, F., Lindenberg, A. M. 2024

  Abstract

  The development of many quantum optical technologies depends on the availability of single quantum emitters with near-perfect coherence. Systematic improvement is limited by a lack of understanding of the microscopic energy flow at the single-emitter level and ultrafast timescales. Here we utilize a combination of fluorescence correlation spectroscopy and ultrafast spectroscopy to capture the sample-averaged dynamics of defects with single-particle sensitivity. We employ this approach to study heterogeneous emitters in two-dimensional hexagonal boron nitride. From milliseconds to nanoseconds, the translational, shelving, rotational and antibunching features are disentangled in time, which quantifies the normalized two-photon emission quantum yield. Leveraging the femtosecond resolution of this technique, we visualize electron-phonon coupling and discover the acceleration of polaronic formation on multi-electron excitation. Corroborated with theory, this translates to the photon fidelity characterization of cascaded emission efficiency and decoherence time. Our work provides a framework for ultrafast spectroscopy in heterogeneous emitters, opening new avenues of extreme-scale characterization for quantum applications.

  View details for DOI 10.1038/s41563-024-01855-7

  View details for PubMedID 38589542

  View details for PubMedCentralID 5615041

• Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation ACS APPLIED NANO MATERIALS McKeown-Green, A. S., Zeng, H. J., Saunders, A. P., Li, J., Shi, J., Shen, Y., Pan, F., Hu, J., Dionne, J. A., Heinz, T. F., Wu, S. M., Zheng, F., Liu, F. 2024

  View details for DOI 10.1021/acsanm.4c00412

  View details for Web of Science ID 001184723800001

• Through thick and thin: how optical cavities control spin. Nanophotonics (Berlin, Germany) Dixon, J., Pan, F., Moradifar, P., Bordoloi, P., Dagli, S., Dionne, J. 2023; 12 (14): 2779-2788

  Abstract

  When light interacts with matter by means of scattering and absorption, we observe the resulting color. Light also probes the symmetry of matter and the result is encoded in its polarization. In the special case of circularly-polarized light, which is especially relevant in nonlinear optics, quantum photonics, and physical chemistry, a critical dimension of symmetry is along the longitudinal direction. We examine recent advances in controlling circularly-polarized light and reveal that the commonality in these advances is in judicious control of longitudinal symmetry. In particular, in the use of high quality-factor modes in dielectric metasurfaces, the finite thickness can be used to tune the modal profile. These symmetry considerations can be applied in multiplexed optical communication schemes, deterministic control of quantum emitters, and sensitive detection of the asymmetry of small molecules.

  View details for DOI 10.1515/nanoph-2023-0175

  View details for PubMedID 39635484

  View details for PubMedCentralID PMC11501721

• Active Control of Plasmonic-Photonic Interactions in a Microbubble Cavity JOURNAL OF PHYSICAL CHEMISTRY C Pan, F., Karlsson, K., Nixon, A. G., Hogan, L. T., Ward, J. M., Smith, K. C., Masiello, D. J., Chormaic, S., Goldsmith, R. H. 2022

  View details for DOI 10.1021/acs.jpcc.2c05733

  View details for Web of Science ID 000894524600001

• Targeted synthesis of a large triazine-based [4+6] organic molecular cage: structure, porosity and gas separation CHEMICAL COMMUNICATIONS Ding, H., Yang, Y., Li, B., Pan, F., Zhu, G., Zeller, M., Yuan, D., Wang, C. 2015; 51 (10): 1976-1979

  Abstract

  Herein, we report the targeted synthesis and solid state assembly of a novel triazine-based [4+6] organic molecular cage. The tetrahedral cage features a large cavity (∼2070 Å(3)), and after desolvation, the resultant material exhibits a high Brunauer-Emmett-Teller surface area of 1181 m(2) g(-1) and also features selective adsorption of CO2 over N2.

  View details for DOI 10.1039/c4cc08883b

  View details for Web of Science ID 000348213200050

  View details for PubMedID 25532049