About

Professor Moonsub Shim is a faculty member in the Materials Science & Engineering department at the University of Illinois at Urbana-Champaign. He earned his Ph.D. in Chemistry from the University of Chicago in 2001, following an M.S. in Chemistry from the same institution in 1998, and a B.S. in Chemistry from the University of California at Berkeley in 1997. His research group focuses on nanorod heterostructures and has previously worked in the area of carbon nanoelectronics. Professor Shim's research interests include the synthesis and characterization of novel II-VI and I-III-VI heterostructures, temperature-dependent heterostructure nanocrystal LED characterization, carrier and exciton dynamics in thin film quantum dot devices, and the study of quantum dots for optoelectronic applications. Throughout his career, he has received several honors including the NSF CAREER Award in 2004, the Xerox Award for Faculty Research in 2007, the Engineering Council Award for Excellence in Advising in 2009, the Willett Faculty Scholar designation from 2010 to 2014, and the Dean's Award for Excellence in Research in 2014. Prior to his current position, he served as the Ivan Racheff Assistant Professor of Materials Science and Engineering from 2002 to 2004.

Research topics

• Optoelectronics
• Materials science
• Chemical engineering
• Nanotechnology
• Physics
• Engineering physics
• Business
• Engineering

Selected publications

• Mg-Doped NiO Hole Transport Layers with Ultrathin ALD-MgO Diffusion Barriers for All-Inorganic Quantum Dot Light-Emitting Diodes

  ACS Applied Nano Materials · 2026-01-06 · 1 citations

  article

  Although hybrid quantum dot (QD) light-emitting diodes (QLEDs) commonly rely on organic hole transport layers, their vulnerability to oxygen and moisture severely limits their long-term stability. Replacing these organics with p-type transparent oxide semiconductors such as NiO offers a chemically and electronically robust alternative; however, the large valence band offset (∼0.6 eV) between the pristine NiO and the 1Sh state of QDs restricts efficient hole injection. In this study, we engineered Mg-doped NiO thin films via a sol–gel process for simultaneously improving p-type conductivity and tailoring valence band alignment with the QD layer. We employed few-cycle atomic layer deposition (ALD) to conformally coat indium tin oxide with an ultrathin (∼1 nm) MgO layer as a diffusion barrier, which suppressed indium ion migration during annealing at 430 °C, thereby preserving interfacial integrity and enhancing device stability. The combination of dopant-modulated NiO and ALD-based diffusion blocking yielded QLEDs with a markedly improved luminance and external quantum efficiency. These results present a viable interface-engineering strategy for developing stable, optimal-performance, and all-inorganic QLED architectures.

  PublisherDOI

• Correction to “Kinetics of Concurrent Seed Growth and Cation Exchange in Transforming Cu _2-x S Nanocrystals to CuGaS ₂ Nanorods”

  Journal of the American Chemical Society · 2026-05-19

  articleSenior author
  PublisherDOI

• Nanofabrication for Nanophotonics

  ACS Nano · 2025-03-28 · 92 citations

  reviewOpen access

  Nanofabrication, a pivotal technology at the intersection of nanoscale engineering and high-resolution patterning, has substantially advanced over recent decades. This technology enables the creation of nanopatterns on substrates crucial for developing nanophotonic devices and other applications in diverse fields including electronics and biosciences. Here, this mega-review comprehensively explores various facets of nanofabrication focusing on its application in nanophotonics. It delves into high-resolution techniques like focused ion beam and electron beam lithography, methods for 3D complex structure fabrication, scalable manufacturing approaches, and material compatibility considerations. Special attention is given to emerging trends such as the utilization of two-photon lithography for 3D structures and advanced materials like phase change substances and 2D materials with excitonic properties. By highlighting these advancements, the review aims to provide insights into the ongoing evolution of nanofabrication, encouraging further research and application in creating functional nanostructures. This work encapsulates critical developments and future perspectives, offering a detailed narrative on the state-of-the-art in nanofabrication tailored for both new researchers and seasoned experts in the field.

  PublisherOA PDFDOI

• <i>(Keynote)</i> Colloidal Quantum Dot and Nanorod Heterostructures

  ECS Meeting Abstracts · 2025-11-24

  article1st authorCorresponding

  Engineering band structure and heterointerfaces has been and continues to be critical for advances in electronics, optoelectronics, photovoltaics, and displays among many high-tech applications. Achieving atomic precision through widely-accessible and cost-effective means would allow rapid advances in these critical areas. The evolution of colloidal semiconductor nanocrystals from single-composition “spherical” particles to complex heterostructures of diverse shapes provides many opportunities for precision band structure engineering through scalable solution synthesis. With anisotropic shapes that can be exploited for assembly, charge carrier manipulation and optical anisotropy, etc., incorporating quantum dots of varying size and composition into colloidal nanorod heterostructures represents an especially promising direction. This talk will first discuss our approaches to the synthesis of nanorod-based colloidal quantum dot heterostructures that can be generalized to achieve a wide range of materials. Examples of how tailored properties of these anisotropic multi-quantum dot heterostructures can bring about improvements and provide multiple new capabilities will then be shown. In particular, emission color switching and multi-functional LEDs that may pave a path to a new generation of displays and beyond are presented.

  PublisherDOI

• Mg-doped NiO hole transport layers with ultrathin ALD-MgO diffusion barriers for all-inorganic quantum dot light-emitting diodes

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• Kinetics of Concurrent Seed Growth and Cation Exchange in Transforming Cu_2-xS Nanocrystals to CuGaS₂ Nanorods

  Journal of the American Chemical Society · 2025-03-04 · 10 citations

  articleSenior authorCorresponding

  Cation exchange can convert nanocrystals that have already been achieved with a well-controlled size, size distribution, and shape to a broad range of compositions. However, cation exchange can often be accompanied by changes in the nanocrystal morphology/shape as exemplified by the synthesis of I–III–VI2 nanocrystals. We examine the temperature-dependent kinetics of concurrently occurring seed epitaxial growth and cation exchange that convert nearly spherical Cu2–xS seeds into CuGaS2 nanorods with varying lengths and degrees of tapering. A simple model is developed to quantify and explain experimentally observed reaction kinetics. Direct epitaxial growth of Cu2–xS seeds occurs with an activation energy of 96 kJ/mol, while cation exchange to convert the growing seed to CuGaS2 requires overcoming a 202 kJ/mol energy barrier. Understanding how each reaction rate evolves over time provides insights into the tapering mechanism and a means of predicting when the onset of tapering occurs. The predicted onset is then exploited to synthesize nanorods with a minimized tapering. Our findings provide the basis for developing precise control over the composition and morphology of nanocrystals synthesized through a combination of cation exchange and solution epitaxy.

  PublisherDOI

• General approach for automated purification of quantum dots using size-exclusion chromatography

  Reaction Chemistry & Engineering · 2025-10-21 · 1 citations

  articleOpen access

  Size-exclusion chromatography demonstrates efficient, one-step purification of crude quantum dot (QD) mixtures to generate high-purity QD fractions.

  PublisherDOI

• Integration of Quantum Dot Light-Emitting Diodes and Charge Trap Thin-Film Transistor Arrays for Memory-In-Pixel Applications

  ACS Applied Materials & Interfaces · 2025-11-14 · 2 citations

  article

  The advancement of ultrahigh-resolution displays and extended reality applications has driven increasing demand for compact and low-power device architectures capable of simultaneously performing memory and light-emission functions at the pixel level. To address this need, charge-trap thin-film transistors (CTTFTs) based on oxide semiconductors have attracted attention as promising nonvolatile memory elements due to their excellent electrical performance and compatibility with large-area fabrication processes. In this study, we propose a memory-in-pixel (MIP) device that monolithically integrates a CTTFT and a quantum dot light-emitting diode (QD-LED) within a single pixel. The fabricated CTTFT, employing an Al2O3/HfO2/Al2O3 gate dielectric and an oxide channel, achieved a field-effect mobility of 22.1 cm2/V·s, a subthreshold swing of 99.1 mV/dec, an on/off current ratio exceeding 109, and a wide memory window of 6.06 V. To enable self-erasing functionality, a QD-LED was monolithically integrated on top of the CTTFT using a photolithography-based lift-off process. The resulting QD-LEDs demonstrated EQEs of 20.9%, 6.5%, and 1.7% for red, green, and blue, respectively. Notably, ZnSeTe-based Cd-free QD-LEDs achieved an erasing efficiency of ∼60%, outperforming their Cd-based counterparts. This hybrid MIP architecture operates without external erase components and offers a compact, environmentally friendly platform suitable for next-generation high-resolution display applications.

  PublisherDOI

• Tunable Near-Infrared Emission from CdSe/CdTe/CdSe Core/Shell/Shell Quantum Dots

  The Journal of Physical Chemistry Letters · 2025-03-20 · 4 citations

  articleSenior authorCorresponding

  Core/shell nanostructures of type I and type II band-offset materials have been pivotal in improving photoluminescence and imparting charge separation in well-established colloidal quantum dots. In addition to these features, the multishell motif provides a simple means to expand the emission spectral range and spatially fine-tune electron and hole wave functions. Here, we explore the CdSe/CdTe/CdSe core/shell/shell structure with a total diameter of ≲7 nm, within the practical limits of readily accessible synthesis capabilities. Systematic variations of the dimensions of the core and the shells are carried out to examine how each of these structural parameters affects optical properties. Emission in the red to near-infrared range from 677 to 1057 nm (1.83 to 1.17 eV), photoluminescence quantum yields of up to 88%, and line widths as narrow as 109 meV (41.8 nm for the peak position of 677 nm) are achieved. Even with a total size limit of ∼7 nm with an ∼1 nm thick CdTe shell, the reddest emission energy can approach the expected energy separation between the bulk CdSe conduction band edge and CdTe valence band edge to within tens of millielectronvolts. Comparison to simple effective mass approximation provides insights and guidelines on achieving independent control over the effective band gap and the electron-hole overlap.

  PublisherDOI

• A high temperature <i>in situ</i> optical probe for colloidal nanocrystal synthesis

  Review of Scientific Instruments · 2024-06-01 · 1 citations

  articleSenior author

  We report on the fabrication and utilization of a robust high-temperature (>300 °C), adjustable-path-length, vacuum-tolerant, configurable, in situ optical probe, which interfaces with widely used chemical glassware via a 14/20 ground glass joint. This probe allows for high-speed reaction monitoring of colloidal semiconductor nanocrystal solutions at temperatures that were previously inaccessible. We demonstrate this capability by monitoring the hot-injection synthesis of CdSe quantum dots via UV-Vis absorption spectroscopy at 380 °C with a time resolution of ∼10 ms, with the primary limitation being the acquisition and data saving rate of the commercial spectrometer used. We further demonstrate that this probe can also be used for in situ photoluminescence measurements. This system is generally applicable to harsh solution environments where optical monitoring of reaction progress is desirable and/or necessary.

  PublisherDOI

Recent grants

• Surface and Interface Effects on Photovoltaic and Light-Emitting Characteristics of Colloidal Nanocrystal Heterostructures

  NSF · $468k · 2018–2022

• Molecular Interfaces to Heterostructures of Low Dimensional Carbon

  NSF · $375k · 2009–2013

• A Scalable Roll-to-Roll Printing Approach to Integrating Nanomaterials into High-Performance Devices

  NSF · $300k · 2014–2017

• Charge Effects on Optoelectronic Properties of Nanorod Heterostructures

  NSF · $390k · 2015–2018

• Reconfigurable Continuous Flow Reactor for Manufacturing of Complex Nanomaterials

  NSF · $400k · 2018–2022

Frequent coauthors

• Philippe Guyot‐Sionnest

  University of Chicago

  26 shared

• Taner Ozel

  University of Illinois Urbana-Champaign

  19 shared

• Steven P. Rogers

  18 shared

• John A. Rogers

  18 shared

• Lane W. Martin

  Lawrence Berkeley National Laboratory

  17 shared

• Congjun Wang

  National Energy Technology Laboratory

  16 shared

• Nuri Oh

  Hanyang University

  16 shared

• Anshu Gaur

  15 shared

Labs

• Shim Research GroupPI

  Materials Science & Engineering

Education

• MS and PhD, Chemistry

  University of Chicago

  2001

• B.S., Chemistry

  University of California Berkeley

  1997

Awards & honors

• Xerox Award for Faculty Research (2007)
• National Science Foundation CAREER Award (2004)
• Racheff Assistant Professorship (2002-2004)
• Willett Faculty Scholar Award (2010-2014)
• Dean's Award for Excellence in Research (2014)