CityUHK Materials, Nanotechnology, Perovskite, and Droplet Electricity Research

CityUHK Integrated Information Database · 04 Research Module
This article focuses on the fields where CityUHK’s Highly Cited Researchers are most concentrated and which drive its Nature Index and patent output—materials science, nanomaterials, mechanical engineering, and electrical/electronic engineering—and traces several landmark breakthroughs (perovskite solar cells, dual-phase nanostructured metals, phase engineering of nanomaterials, terahertz/millimetre-wave) using verifiable sources. Four deeper dive articles cover the following threads: High-Entropy Alloys & Advanced Metals, Zhang Hua & Phase Engineering of Nanomaterials, Perovskite Solar Cells, and Wang Zuankai & the Droplet Electricity Generator.
Platform institutions (SKLTMW, NPMM, CASM) are covered in institutes-and-labs.md; a person-by-person list of Highly Cited Researchers appears in named-centres-and-honours.md; patent translation is in output-and-startups.md.

If you had to explain where CityUHK’s research excellence lies using a single table, the row for materials science would be in bold. In 2024, the top materials journal Advanced Materials devoted a special issue to CityUHK with a title that verges on boastful: “Three Decades of Materials Research Excellence at CityU”. For a university barely over forty years old—and smaller in scale among Hong Kong’s eight UGC-funded institutions—to have a leading peer journal dedicate an entire issue to reviewing its “three decades of materials research excellence” is, in itself, a form of peer endorsement.

# 1. Why Materials/Engineering Is CityUHK’s Calling Card

When CityUHK’s research output is broken down, materials science and engineering stands out as the core engine of its international visibility:

• Concentration of Highly Cited Researchers: A substantial proportion of CityUHK’s 32 Clarivate Highly Cited Researchers in 2025^※ are concentrated in materials science, chemistry, and nanomaterials (individual profiles are in named-centres-and-honours.md).
• 30th-anniversary special issue endorsement: In 2024, as CityUHK marked the 30th anniversary of being granted university status, the leading materials journal Advanced Materials published a “Three Decades of Materials Research Excellence at CityU” special issue^※, systematically reviewing thirty years of materials research at CityUHK—a public recognition by peers of its status in materials science.
• Platform support: The State Key Laboratory of Terahertz and Millimeter Waves (SKLTMW), the Hong Kong Branch of the National Engineering Research Center for Precious Metal Materials (NPMM), the Centre for Advanced Structural Materials (CASM), and others all fall within the materials/engineering direction (see institutes-and-labs.md).

Below, the representative breakthroughs are laid out along four lines: Energy Materials → Structural Materials → Nanoscience → Electronic/Electromagnetic Engineering.

# 2. Landmark Breakthrough (I): The Thermal Stability Challenge in Perovskite Solar Cells

The narrative (based on CityUHK press releases and the Science paper). Perovskite solar cells are known for their high power conversion efficiency, but they have long been plagued by thermal instability, which hinders commercialisation. According to a CityUHK press release (2023-10-20)^※, a team led by Professor Zhu Zonglong of the Department of Chemistry designed a self-assembled monolayer (SAM) and anchored it to the surface of nickel oxide nanoparticles as a charge-extraction layer, thereby markedly improving the device’s thermal stability.

Per that report, the improved device, after operating continuously at around 65°C for more than 1,000 hours, retained over 90% of its efficiency, achieving a power conversion efficiency of 25.6%. The related paper, titled “Stabilized hole-selective layer for high-performance inverted p-i-n perovskite solar cells,” was published in Science and is a collaboration with Professor Li Zhongan of Huazhong University of Science and Technology (HUST) on the mainland (according to the CityUHK press release (2023-10-20)^※). Further details of this research line—including two earlier breakthroughs in interface engineering and non-volatile additives, and the later collaboration with the U.S. National Renewable Energy Laboratory (NREL) to address scale-up bottlenecks—can be found in the dedicated article Perovskite Solar Cells.

This work represents CityUHK’s energy materials direction well: it aligns with both national and global demands for clean energy and fits into the on-campus framework of the Hong Kong Institute for Clean Energy (HKICE) (see institutes-and-labs.md).

# 3. Landmark Breakthrough (II): Dual-Phase Nanostructuring—Making Magnesium Alloys Approach Theoretical Strength

The narrative (based on the Nature paper). CityUHK’s College of Engineering has a long-standing track record in high-strength structural materials. According to the Nature paper “Dual-phase nanostructuring as a route to high-strength magnesium alloys” (2017)^※, the research team proposed a dual-phase nanostructuring approach: embedding sub-10-nanometre nanocrystalline grains within an amorphous glass shell to produce magnesium-alloy thin films that combine ultrahigh strength with high deformability.

According to that paper and related CityUHK reports, the resulting dual-phase material achieved a strength close to the near-ideal limit, about 3.3 GPa—roughly 10 times stronger than conventional crystalline magnesium alloys—and a super-deformability approximately 2 times that of magnesium-based metallic glass. Because magnesium is biodegradable, the material is cited as a candidate for degradable medical implants (according to a CityUHK research story (2017)^※).

The leading figure in this direction, Professor Jian Lu (Chair Professor of Mechanical Engineering, Dean of the College of Engineering, and Senior Fellow of the Hong Kong Institute for Advanced Study (HKIAS)), has an extensive publication record in experimental mechanics, residual stress, and structural materials, with work frequently appearing in Nature, PNAS, Nature Communications, and Science Advances (for Lu’s academician honours, see named-centres-and-honours.md). This structural-materials line has produced a further series of breakthroughs in the even more cutting-edge branch of high-entropy alloys—from “cobalt-mediated inhibition of nanoparticle coarsening” to new mechanisms that break the strength–ductility trade-off—detailed in the dedicated article High-Entropy Alloys & Advanced Metals.

# 4. Landmark Breakthrough (III): Phase Engineering of Nanomaterials (PEN)

The narrative (based on the CityUHK research story page). Professor Zhang Hua (Herman Hu Chair Professor of Nanomaterials), of the Department of Chemistry, proposed and systematically developed the concept of Phase Engineering of Nanomaterials (PEN)—that is, treating phase as a structural parameter on a par with composition, morphology, size, and dimensionality, and designing the properties and functions of nanomaterials by controlling their phase (according to a CityUHK research story (2020-05-21)^※).

At its core, PEN involves synthesizing metallic and two-dimensional (2D) nanomaterials with unconventional phases and epitaxially growing heterostructures to serve a variety of applications. Zhang is one of the most highly cited scholars in materials/chemistry, consistently named a Clarivate Highly Cited Researcher (see named-centres-and-honours.md), and PEN has become one of CityUHK’s signature concepts in nanoscience visible to the outside world. The full arc—from the first synthesis of hcp-phase gold square nanosheets using a graphene oxide template to the institutionalisation of the field as the “Nature Conference on Phase Engineering of Nanomaterials 2024”—is traced in the dedicated article Zhang Hua & Phase Engineering of 2D Nanomaterials.

# 5. Electrical/Electronic Engineering: Terahertz, Millimetre-Wave, and 6G

In the electrical/electronic engineering direction, CityUHK’s flagship is the State Key Laboratory of Terahertz and Millimeter Waves (SKLTMW)—the first State Key Laboratory in Hong Kong’s engineering field, approved by the Ministry of Science and Technology in March 2008 (see institutes-and-labs.md for details). Its core areas include:

• Antenna design (including high-performance antennas for millimetre-wave/terahertz bands);
• Radio-frequency integrated circuit (RFIC) design;
• Fast computational electromagnetics methods;
• Cutting-edge applications for 6G communications, terahertz imaging, and spectroscopy.

This line brings together CityUHK’s research in wireless communications, electromagnetics, and integrated circuits under a single national-level platform and is a significant source of its engineering-related U.S. patents (for patents, see output-and-startups.md).

# 6. Mechanical Engineering & Advanced Manufacturing: From Aircraft Skin to Electricity from a Raindrop

Beyond structural materials, CityUHK’s mechanical engineering strength extends into additive manufacturing (3D/4D printing), metallic glass, advanced alloys, and bio-inspired surfaces. Related teams have published review works on scientific advances in 2D/3D/4D additive manufacturing^※ and have collaborated with mainland institutions to develop fatigue-resistant 3D-printed aluminium alloys, among others (per CityUHK and partner reports). Much of this work is integrated with platforms such as NPMM and CASM (see institutes-and-labs.md).

Under the same mechanical engineering umbrella, but taking a radically different approach, is bio-inspired surface science. The team led by Chair Professor Wang Zuankai, of the Department of Mechanical Engineering, started from the principle of lotus leaves repelling water and pushed all the way to a 2020 Nature cover result: a field-effect transistor–type droplet electricity generator that, when struck by a water droplet falling from a height of 15 cm, can instantaneously light up 100 small LED bulbs. The full research line—from “superhydrophobicity” to “electricity generation” and on to the 266-year-old Leidenfrost puzzle—is covered in the dedicated article Wang Zuankai & the Droplet Electricity Generator.