About

Longji Cui is an Assistant Professor in the Paul M. Rady Mechanical Engineering department at the University of Colorado Boulder. His research focuses on thermal energy sciences, ultrahigh resolution sensors, scanning probe microscopy, nano-optics, and quantum engineering. His group develops high precision instrumentation and computational techniques to explore energy transport, conversion, and dissipation at extreme scales, with interdisciplinary work spanning scanning thermal microscopy, picowatt resolution thermal sensors, atomic and molecular-scale electronics, and thermophotovoltaics. His research addresses critical societal challenges related to affordable and sustainable energy, next-generation microelectronics, and advanced materials and sensors for high-performance applications. Longji Cui has received several awards, including the NSF CAREER Award in 2023 and the ASME Rising Star Award in 2024.

Research topics

• Optics
• Materials science
• Optoelectronics
• Physics
• Condensed matter physics
• Atomic physics
• Molecular physics

Selected publications

• Formation of an Amorphous LaAlBO _x Overlayer on Crystalline LaAlO ₃ Perovskite for Highly Efficient and Stable Propane Oxidative Dehydrogenation

  Angewandte Chemie International Edition · 2026-05-14

  article

  ABSTRACT Supported boron oxide catalysts have demonstrated ultra‐high selectivity in the oxidative dehydrogenation of propane (ODHP), but their practical deployment is severely limited by poor thermal stability and rapid deactivation, primarily due to the hydrolysis of active B–O sites forming volatile boric acid. Here, we develop a catalyst comprising a crystalline LaAlO 3 (LAO) perovskite coated with an amorphous LaAlBO x overlayer, achieved through the thermal treatment of physically mixed H 3 BO 3 and LAO. During reaction, the amorphous LaAlBO x overlayer grows in thickness, wherein the concurrent formation of strong M–O–B (M = La, Al) bonds effectively suppress boron volatilization, ensuring long‐term structural stability. The optimized catalyst achieves a propylene yield of 21% and a total olefin selectivity of 97% during continuous operation at 500°C for 100 h, which ranks among the top‐tier performance reported in the literature. Density functional theory (DFT) calculations demonstrate that the formation of M–O–B bonds not only stabilizes boron species from volatilization but also lowers the energy barrier of the rate‐determining‐step in ODHP, thereby leading to remarkable catalytic performance. Importantly, this strategy is found to be extendable to other perovskites (e.g., SmAlO 3 , SrTiO 3 , BaTiO 3 ), underscoring its generality for designing durable boron‑based catalysts.

  PublisherDOI

• Formation of an Amorphous LaAlBO _x Overlayer on Crystalline LaAlO ₃ Perovskite for Highly Efficient and Stable Propane Oxidative Dehydrogenation

  Angewandte Chemie · 2026-05-14

  article

  ABSTRACT Supported boron oxide catalysts have demonstrated ultra‐high selectivity in the oxidative dehydrogenation of propane (ODHP), but their practical deployment is severely limited by poor thermal stability and rapid deactivation, primarily due to the hydrolysis of active B–O sites forming volatile boric acid. Here, we develop a catalyst comprising a crystalline LaAlO 3 (LAO) perovskite coated with an amorphous LaAlBO x overlayer, achieved through the thermal treatment of physically mixed H 3 BO 3 and LAO. During reaction, the amorphous LaAlBO x overlayer grows in thickness, wherein the concurrent formation of strong M–O–B (M = La, Al) bonds effectively suppress boron volatilization, ensuring long‐term structural stability. The optimized catalyst achieves a propylene yield of 21% and a total olefin selectivity of 97% during continuous operation at 500°C for 100 h, which ranks among the top‐tier performance reported in the literature. Density functional theory (DFT) calculations demonstrate that the formation of M–O–B bonds not only stabilizes boron species from volatilization but also lowers the energy barrier of the rate‐determining‐step in ODHP, thereby leading to remarkable catalytic performance. Importantly, this strategy is found to be extendable to other perovskites (e.g., SmAlO 3 , SrTiO 3 , BaTiO 3 ), underscoring its generality for designing durable boron‑based catalysts.

  PublisherDOI

• Inductance meets memory in a quantum magnet

  Communications Physics · 2026-04-11

  articleOpen access

  Orbital degrees of freedom offer a largely untapped route to emergent dynamical phenomena in correlated quantum materials. However, it remains unclear whether collective orbital states can intrinsically generate both reactive and memory functionalities in a bulk system. Here we show that in the ferrimagnet Mn3Si2Te6, nonequilibrium reconfiguration of chiral orbital currents produces both emergent inductance and nonvolatile memristance as intrinsic properties of a single crystal. At low frequency and under a magnetic field along the c axis, coherent orbital-current domains generate robust clockwise inductive I-V loops. At higher frequency and low field, current-driven first-order reconfiguration leads to incomplete reversal and metastable trapping, producing an intrinsic electromotive force and a finite remanent voltage at zero current. These results establish orbital currents as a class of quantum state variables that encode both reactive and memory functionalities, opening routes toward intrinsically reconfigurable and energy-efficient electronic systems.

  PublisherDOI

• Author Correction: Manipulating d-orbital of Cu single atom site by coordination engineering for selective oxidation of benzene

  Nature Communications · 2026-02-20

  articleOpen access
  PublisherOA PDFDOI

• Ultralow-loading Pt single atoms anchored on N-doped carbon-encapsulated Mo ₂ C microspheres for efficient hydrogen evolution

  Journal of Materials Chemistry A · 2026-01-01 · 1 citations

  article

  Ultralow-loading Pt single atoms anchored on N-doped carbon-coated Mo 2 C microspheres exhibit exceptional HER performance.

  PublisherDOI

• Zero-Vacuum-Gap Thermophotonics

  PRX Energy · 2026-01-06

  articleOpen accessSenior author

  Thermophotonic (TPX) devices offer a promising pathway to overcome the power density and efficiency trade-offs of thermophotovoltaics (TPVs) by using biased light-emitting diodes (LEDs) as active infrared photon emitters. However, practical implementation of TPXs has been limited by stringent demands requiring the LED to operate at high temperatures, as well as the need for near-perfect external quantum efficiency (EQE) to enable self-sustaining (i.e., no external power supply) operation. Here, we introduce a zero-vacuum-gap thermophotonic (zTPX) architecture that integrates a high-refractive-index solid-state spacer between the LED and the photovoltaic cells, which forms an optical cavity that minimizes index mismatch and enables high photon concentration. This design enhances both power density and efficiency, over 40-fold power improvement, and up to doubled efficiency enhancement compared to conventional far-field TPX, allowing the operation of TPXs at relatively lower temperatures, at which high-performance LEDs are available. Furthermore, we show that the zTPX structure achieves a record-breaking EQE of approximately 98%, which enables a self-sustaining TPX circuit with a sizable power output. These combined performance gains position zTPX as a highly practical thermophotonic solution for thermal energy conversion and utilization at low to moderate temperatures (<1000 °C), including industrial waste-heat recovery, distributed power generation, and portable heat-to-electricity converters.

  PublisherDOI

• New materials, old physics – the science behind how your winter jacket keeps you warm

  2025-12-26

  articleOpen access1st authorCorresponding
  PublisherDOI

• Near-Field Thermal Radiation as a Probe of Nanoscale Hot Electron and Phonon Transport

  ACS Nano · 2025-02-10 · 9 citations

  articleOpen accessSenior authorCorresponding

  Understanding the energy transport properties of hot energy carriers is of great importance for a diverse range of topics from nanoelectronics and photochemistry to the discovery of quantum materials. While much progress has been made in the study of hot carrier dynamics using ultrafast far-field time-resolved spectroscopies, it remains a great challenge to understand hot carrier transport and interaction dynamics at the nanoscale. Existing theoretical models yield only qualitative predictions that are difficult to validate against experiments. Here we present a theoretical framework that extends the study of near-field thermal radiation into the ultrafast time domain, enabling sensitive local probing and quantitative study of nanoscale hot electron and phonon transport effects that have been challenging to quantify. The proposed technique of near-field hot carrier nanoscopy directly links the features of different nonequilibrium effects to near-field thermal absorption and scattering by a scanning nanotip. Our model predicts ultrafast thermal radiation in response to photoexcitation, as well as elucidates the nanoscopic radiation properties of a number of hot carrier dissipation pathways, including nonlinear electron supercollision, second sound, and nonlocal phonon transport. This work is expected to guide experiments to identify the fundamental constraints unlocking thermal wave (second sound) propagation and address the roles of competing hydrodynamic and ballistic phonon effects at the nanoscale.

  PublisherOA PDFDOI

• Manipulating d-orbital of Cu single atom site by coordination engineering for selective oxidation of benzene

  Nature Communications · 2025-07-01 · 21 citations

  articleOpen access

  Single-atom catalysts (SACs) enable atomic-level control over active sites, but orbital-level manipulation to steer catalytic behavior remains challenging. Here, we address this issue through d-orbital engineering of Cu SACs, achieving simultaneous control over coordination geometry (Cu-N3) and high metal loading (33.2 wt%) for direct benzene-to-phenol oxidation with H2O2. The tri-coordinated Cu SAC (Cu-N3-33.2) exhibits the highest performance with 85.8% benzene conversion and a turnover frequency of 680.3 h−1 at 60 oC, ranking it among the best metal-based catalysts. In-situ ATR-IR spectroscopy and DFT calculations reveal that dynamically formed Cu-O intermediates, driven by p-d orbital hybridization between Cu (d orbitals) and O (p orbitals), lower the H2O2 activation barrier by 0.98 eV compared to Cu-N4 sites. High-density atomic Cu sites prevent over-oxidation by consuming singlet oxygen (1O2). This work establishes a dual-parameter optimization paradigm, including orbital configuration and site density, redefining design principles for selective oxidation SACs. Single-atom catalysts provide atomic-level control over active sites but often lack orbital-level manipulation. Here the authors demonstrate orbital engineering of a Cu catalyst, achieving control over coordination geometry and high metal loading.

  PublisherOA PDFDOI

• On-chip single-crystal plasmonic optoelectronics for efficient hot carrier collection and photovoltage detection

  Light Science & Applications · 2025-09-16 · 1 citations

  articleOpen accessSenior author

  Large-area chemically synthesized single-crystal metals with nanometer-scale thickness have emerged as promising materials for on-chip nanophotonic applications, owing to their superior plasmonic properties compared to nanofabricated polycrystalline counterparts. While much recent attention has focused on their optical properties, the combined optimal electrical and optical characteristics, which hold great potential for high-performance optoelectronic functionalities, remain largely unexplored. Here, we present a single-crystal plasmonic optoelectronic platform based on nanowires fabricated from synthesized gold flakes and demonstrate its capabilities for highly enhanced hot carrier collection, electroluminescence, and photovoltage detection. Notably, single-crystal gold nanogap devices exhibit an order of magnitude higher open-circuit photovoltage compared to polycrystalline devices, representing one of the highest reported photovoltage sensing performances in terms of on-chip device density and responsivity per area. Our analysis revealed that this enhancement is attributed mostly to the suppression of electron-phonon scattering and improved hot carrier tunneling efficiency in single-crystal devices. These results highlight the potential of large-scale single-crystal nanostructures for both fundamental studies of nanoscale hot carrier transport and scalable electrically driven nanophotonic applications.

  PublisherDOI

Recent grants

• CAREER: Fundamental Understanding of Thermal Transport at the Single Molecule Level

  NSF · $554k · 2023–2028

Frequent coauthors

• Douglas Natelson

  Rice University

  14 shared

• Edgar Meyhöfer

  University of Michigan–Ann Arbor

  12 shared

• Pramod Reddy

  University of Michigan–Ann Arbor

  11 shared

• Yunxuan Zhu

  Nanjing University of Chinese Medicine

  10 shared

• Mahdiyeh Abbasi

  Urmia University

  7 shared

• Peter Nordlander

  Rice University

  6 shared

• Juan Carlos Cuevas

  5 shared

• Wonho Jeong

  University of Michigan–Ann Arbor

  5 shared

Awards & honors

• CEAS Innovation & Entrepreneurship Fellow, CU Boulder (2025)
• ASME Rising Star Award (2024)
• NSF CAREER Award (2023)
• Lab Venture Challenge Award, CU Boulder (2023)
• J. Evans Attwell-Welch Fellowship, Rice University (2018)