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Computationally Guided Synthesis Creates High-Efficiency Tin Halide Perovskite Nanocrystals

Researchers at The Hong Kong Polytechnic University (PolyU) have developed a dual-defect suppression strategy, achieving record-breaking luminescence in lead-free quantum materials, opening new possibilities for advanced optoelectronic applications. Lead-free perovskite nanomaterials are regarded as safer and more environmentally friendly alternatives for next-generation optoelectronic devices. However, tin halide perovskite nanocrystals have suffered from poor luminescence. Prof. Jun YIN, Assistant Professor of the Department of Applied Physics at PolyU, has addressed this challenge through computationally guided dual-defect suppression strategy, achieving a record photoluminescence quantum yield (PLQYs) of 42.4%, more than 80 times higher than previous reports. In recent years, perovskite nanocrystals have attracted growing attention for use in optoelectronic devices that are closely connected to our daily life, ranging from the vibrant displays of smartphones and televisions to the next-generation of solar cells and photodetectors. However, the most efficient perovskite materials to date have relied heavily on lead, a toxic element that poses significant environmental and health risks. This has spurred an urgent search for safer, lead-free alternatives that do not compromise on performance. Among the most promising candidates are tin halide perovskite nanocrystals, which have the potential to replace lead in perovskite-based devices and pave the way for a new era of sustainable quantum materials. Despite this promise, tin-based perovskites have been plagued by low PLQYs and poor stability, limiting their practical application. These challenges stem largely from the complex defect chemistry of tin halide perovskites, which has so far resisted conventional synthetic strategies. To address this long-standing challenge, Prof. YIN and his research team leverage computational insights to guide the synthesis of tin halide perovskite nanocrystals with unprecedented luminescence. Their key breakthrough was the development of a dual-defect suppression strategy that combines tin-rich reaction conditions with the incorporation of exogenous monovalent cations, thereby suppressing both bulk and surface defects. Using this approach, the team successfully synthesized FASnI3 (FA = formamidinium) nanocrystals with a PLQY of 42.4% ± 1.0%, more than 80 times higher than previously reported for this material. This breakthrough, published in Nature Synthesis, not only deepen the understanding of defect chemistry in tin perovskites, but also provides a practical pathway toward high-performance, lead-free quantum materials for optoelectronic applications. This study demonstrates that computationally guided synthesis, grounded in a deep understanding of defect chemistry, can unlock the full potential of tin halide perovskite nanocrystals as high-efficiency, lead-free quantum materials. Source: Innovation Digest

PolyU and Anker Innovations establish joint laboratory to accelerate commercialisation of smart home products

The Hong Kong Polytechnic University (PolyU) and Anker Innovations Technology Co., Ltd (Anker Innovations) signed a collaboration agreement on 21 April to officially establish the “PolyU-Anker Innovations Joint Laboratory”, marking a new milestone in industry-university-research collaboration in the field of artificial intelligence (AI). The Joint Laboratory will focus on the research and development of on-device AI technologies, aiming to accelerate the intelligent upgrade of home devices and promote the widespread application of related technologies in the international market. The signing ceremony was held on the PolyU campus. Witnessed by Prof. Jin-Guang TENG, PolyU President and Mr Steven YANG, Founder and CEO of Anker Innovations, the agreement was signed by Prof. Christopher CHAO, PolyU Senior Vice President (Research and Innovation) and Mr Frank ZHU, President of Smart Home at Anker Innovations. Subsequently, Prof. Jin-Guang Teng; Prof. Christopher Chao; and Prof. Hongxia YANG, Executive Director of the PolyU Academy for Artificial Intelligence (PAAI) and Director of the PolyU-Anker Joint Laboratory, together with Mr Steven Yang and Mr Frank Zhu, officiated at the unveiling ceremony of the Joint Laboratory. This collaboration will leverage PolyU research strengths in AI models, chip-level optimisation and model fusion, as well as Anker Innovations’ extensive industry experience in the global smart hardware market. Together, they will build a collaborative innovation model of “university research and development + industrial application” to promote the commercialisation of research outcomes. In his address, Prof. Jin-Guang Teng outlined PolyU’s strategic positioning. He noted that PolyU is a research university that actively responds to the Nation’s development strategy and aligns closely with the needs of industry and society. He emphasised that research outcomes should not only be targeted at publication in top international journals, but also be translated into technologies and products that benefit society. PolyU has high-calibre research teams in the field of AI and has established PAAI as a strategic development platform to drive the practical application of AI technologies, contributing to Hong Kong’s development as an international innovation and technology hub and supporting the Nation’s innovation-driven development strategy. Through its collaboration with Anker Innovations, PolyU hopes to accelerate the commercialisation of PolyU research outcomes and enhance the competitiveness of Anker Innovations’ products in the international market, achieving mutual benefit and common development. Mr Steven Yang said, “Anker Innovations has always been committed to enhancing the intelligent experience of consumer electronics products through advanced technology. PolyU’s deep expertise in cutting-edge AI research is highly complementary to our strengths in product definition, scenario implementation and global marketing. The Joint Laboratory will act as an accelerator for technological innovation, promoting the widespread application of on-device AI in home hardware scenarios.” The Joint Laboratory will be jointly managed by PAAI and Anker Innovations’ technical team. Initial research will focus on low-precision training, inference and fusion technologies for on-device models, promoting the localised learning and deployment of large AI models. While balancing computational efficiency and cost-effectiveness, it will further enhance user privacy protection to address core market demands for smart home devices. Through the Joint Laboratory, both parties aim to align with the Nation’s innovation-driven development strategy, leading the smart home industry’s transition from “connected intelligence” towards “decision intelligence”.

PolyU and Geely Farizon establish joint lab to promote methanol-electric mobility for a carbon-neutral Hong Kong

The Hong Kong Polytechnic University (PolyU) and Geely Farizon New Energy Commercial Vehicle Group (Geely Farizon) recently held a signing ceremony on the PolyU campus to officially establish the “PolyU–Farizon Transport and Energy Joint Laboratory” (the Joint Lab), focusing on industrial development policies in relation to methanol-electric technologies, promoting their development across technical, economic, and social dimensions, and building a new methanol ecosystem to help Hong Kong achieve its carbon neutrality goals. PolyU possesses robust capabilities in engineering, construction, and environmental sciences. Its Department of Land Surveying and Geo-Informatics (LSGI) has a proven track record in green transport, energy policy, and smart city development, generating significant impact in the low-carbon transport sector. This new collaboration will leverage PolyU interdisciplinary research capabilities to provide solid academic support for the emerging methanol ecosystem. The signing ceremony was witnessed by Prof. Christopher CHAO, Senior Vice President (Research and Innovation) of PolyU; Prof. LI Xiangdong, Dean of the Faculty of Construction and Environment of PolyU; Mr Mike FAN, Chief Executive Officer of Geely Farizon; and Ms DAI Huifang, Principal of Geely Academy, Geely Holding Group. The MoU was signed by Prof. CHEN Wu, Head of LSGI at PolyU, and Dr SONG Zhaohuan, Vice President and Chief Brand Officer of Geely Farizon. A project agreement marking the official launch of research on methanol‑electric vehicles in Hong Kong was subsequently signed by Prof. ZHUGE Chengxiang, Assistant Professor of LSGI at PolyU, and Mr Jack YANG, Head of Hong Kong Project Team at Geely Farizon, in the presence of senior leaders and scholars from both sides. In his welcoming remarks at the ceremony, Prof. Christopher Chao said, “PolyU is delighted to join hands with Geely Farizon to embark on this new journey of industry-academia-research collaboration. This collaboration marks a crucial step forward in advancing Hong Kong’s green and low-carbon transportation, contributing directly to the carbon neutrality targets set out in the ‘Hong Kong Climate Action Plan 2050’. By leveraging PolyU’s strengths in scientific and policy research alongside Geely Farizon’s deep industry expertise, we aim to provide evidence-based policy recommendations for green transport governance and offer citizens cleaner, more efficient travel options.” Mr Mike Fan stated, “PolyU brings together top global research talent and features deep industry-academia integration, making it one of the most pioneering and influential universities in Hong Kong. PolyU and Geely Farizon share a highly aligned vision for green transportation. Together, we will write a new chapter in energy transition for Hong Kong, promote high-quality green development in the Greater Bay Area, and bring Chinese solutions to the global stage.” The Government of the Hong Kong Special Administrative Region is actively promoting the green transformation of vehicles and increasing the proportion of renewable energy usage. The Government’s initiatives create a favourable innovation environment for developing a methanol ecosystem in Hong Kong. Backed by Geely Farizon’s industry resources and PolyU research expertise, the Joint Lab will focus on three major research directions: research on policies for promoting and popularising methanol-electric technologies in the public transport sector; development of a smart energy supply operation platform tailored to Hong Kong’s green transport policies and urban traffic scenarios; and feasible solutions and advisory reports for the local introduction of methanol-electric vehicles. Furthermore, methanol-electric industry-academia-research fund and expert network will be established to provide comprehensive support for the effective integration of transportation and energy. Since initiating their partnership last year, PolyU and Geely Farizon have rapidly advanced exploratory work on methanol-electric applications in Hong Kong, in the areas of transportation, and methanol trade, storage, and refuelling. At the Intelligent Electric Vehicle Development Forum 2026, both parties witnessed the launch of the “Global Methanol-Electric Ecosystem Alliance”, of which they are both members. The Alliance’s first core event will be held in Hong Kong this June, showcasing the latest developments in the methanol-electric industrial ecosystem and demonstrating to the world the robust technological strength and ecological advantages of China’s methanol-electric solutions.

National Wind Power Generation Technology Innovation Center visited PolyU, jointly fostering green energy innovation

A delegation from the National Wind Power Generation Technology Innovation Center (the Center) visited The Hong Kong Polytechnic University (PolyU) on 17 April, hosting a technical collaboration seminar and a campus recruitment event. The visit marked a new milestone in industry–academia–research collaboration and strengthened university–industry partnerships. The seminar focused on cutting‑edge topics such as advanced materials for offshore engineering, innovative structural design, and wind power technologies. With a focus on global energy transition and China’s “dual‑carbon” objectives, both parties aimed to integrate PolyU’s expertise in advanced materials and structural engineering with the Center’s leadership in wind power technology commercialisation, in order to tackle future challenges in green energy development. In addition, a Goldwind campus recruitment event attracted PolyU students and early‑career researchers, offering career and internship opportunities related to wind energy technologies, materials science, and sustainable energy, and creating a direct talent pipeline between academia and industry. Looking ahead, PolyU will continue to embrace an open and innovative approach, working closely with national research institutions to drive breakthroughs in green energy technologies and talent development, contributing to long‑term sustainability and carbon neutrality.

International CCUS Technology Innovation Cooperation Organization visited PolyU to foster collaboration on energy and sustainable development

The International CCUS Technology Innovation Cooperation Organization visited The Hong Kong Polytechnic University (PolyU) on 17 April to exchange views on energy and sustainable development, and to foster potential in-depth collaboration. The delegation was received by Prof. Jin-Guang Teng, PolyU President, Prof. Christopher Chao, Senior Vice President (Research and Innovation), Prof. Raymond Wai-Yeung Wong, Dean of Faculty of Science, Prof. Yung Ka-fu, Associate Dean of Faculty of Science, Prof. Chow Ming-cheung, Head and Professor of the Department of Applied Biology and Chemical Technology, and Prof. Chen Sheng, Head of Department of Food Science and Nutrition and Chair Professor of Microbiology. The visiting delegation from the International CCUS Technology Innovation Cooperation Organization included Prof. Li Yang, Secretary-General of the Organization, Academician of the Chinese Academy of Engineering and Chief Scientist of Sinopec; Mr Xue Zhaojie, Expert of Sinopec Group; Mr Wang Rui, Deputy Director of the Enhanced Oil Recovery Technology Research Institute of the Sinopec Petroleum Exploration and Production Research Institute, Mr Gao Ran, Expert of the Sinopec Petroleum Exploration and Production Research Institute, and Mr Pan Jie, Senior Engineer of Sinopec Petroleum Engineering Design Co., Ltd. In welcoming remarks, Prof. Teng said that PolyU is committed to pursuing excellence in talent nurturing, scientific research and knowledge transfer, to contribute to the Nation, Hong Kong and the global community. He highlighted PolyU’s strong international standing in engineering and technology disciplines and expressed gratitude to Sinopec for its longstanding support for PolyU’s education and research efforts, including the establishment of a dedicated scholarship for the fourth consecutive year to recognise outstanding doctoral students engaged in university–industry collaborative research. Prof. Li Yang said that, to accelerate global innovation and industrial development of CCUS technologies, Sinopec has taken the lead in establishing the International CCUS Technology Innovation Cooperation Organization, in collaboration with leading global enterprises and distinguished scientists. The Organization brings together enterprises, universities, research institutions and industry organizations to form a diversified, cross‑sector global innovation network. Looking ahead, the Organisation hopes to work with PolyU to advance international cooperation in low-carbon innovation technologies, build platforms for global technology exchange, and drive frontier research and technological breakthroughs.” The International CCUS Technology Innovation Cooperation Organization, established in July 2025 under the leadership of Sinopec, is the first international organisation initiated by China dedicated to carbon science and technologies. Upholding the mission of “Innovating Carbon Pathways, Sharing a Sustainable Future”, the Organisation seeks to develop a credible, influential and authoritative international CCUS platform, promote global knowledge sharing, and foster collective action to combat climate change and build a shared future for humanity.    

Media report: PolyU Top 10 Research & Innovation Stories of the Year drive global sustainability

The Hong Kong Polytechnic University (PolyU) has unveiled its “PolyU Top 10 Research & Innovation Stories of the Year,” showcasing a series of groundbreaking achievements that underscore the University’s commitment to advancing global sustainability and technological progress. Selected through over 7,700 public votes and expert review, the featured top 10 research and innovation stories span key areas such as carbon reduction, renewable energy development, and advancements in medical diagnostics and treatment, delivering meaningful impact across society, the environment, and the economy. PolyU Top 10 Research & Innovation Stories not only demonstrate PolyU’s leadership in research and innovation but also reflect its long‑term dedication to advancing the United Nations Sustainable Development Goals (SDGs). PolyU researchers are committed to developing solutions that benefit society and support sustainable development worldwide. PolyU remains firmly committed to addressing global challenges through research excellence and innovation. By fostering interdisciplinary collaboration and accelerating the translation of discoveries into real‑world applications, the University aims to deliver tangible benefits to society and global development.  

PolyU and CLP Power co-develop smart “Generator Inspection Robot”, spearheading innovative solutions through academia-industry synergy to drive research translation and talent development

The Hong Kong Polytechnic University (PolyU) and CLP Power Hong Kong Limited (CLP Power) have jointly developed a smart “Generator Inspection Robot”. By integrating robotics with fibre-optic sensing technology for generator inspections, the project overcomes traditional manual inspection limitations, significantly enhancing the efficiency of inspections and operational safety. The project won a Gold Medal and a special prize—Best International Invention & Innovation, from the National Research Council of Thailand—at the 51st International Exhibition of Inventions Geneva. This international recognition testifies to the achievements of PolyU and CLP Power in fostering industry-academia-research collaboration, injecting momentum into Hong Kong’s development in innovative technology and research talent. A highly reliable electricity supply is vital to the city’s social and economic development. As a core facility of the power system, generator inspection and maintenance always require a high level of technical expertise and stringent safety standards. A generator primarily comprises the stationary outer component “stator” and the internal rotating component “rotor”. Traditional inspections require the removal of the rotor that weighs approximately 50 tonnes, a complex process involving heavy lifting operations and extensive logistical arrangements. In light of the unique design of some gas-fired generators at CLP Power’s Black Point Power Station, which incorporate internal ventilation baffles, no suitable robotic inspection solutions had previously been available on the market. In response to this operational need, Prof. TAM Hwa-yaw, Chair Professor of Photonics of the Department of Electrical and Electronic Engineering at PolyU, led a team of researchers and undergraduates to collaborate with CLP Power’s Generation Business Group to develop a 36‑millimetre‑thick “Generator Inspection Robot” specifically designed to suit the structural characteristics of the generators concerned. The robot can flexibly navigate the narrow air gaps between the rotor and the stator, and cross the ventilation baffles inside to automatically complete major inspection tasks without removing the rotor. These inspections include visual checks of ventilation ducts, assessing the insulation condition of stator core laminations and conducting wedge tightness inspections through tapping. Compared to manual inspection, the robot helps enhance inspection efficiency while optimising long-term maintenance arrangements. The robot is also equipped with a fibre-optic sensing network to monitor the operational status of its own key components. This ensures its operational stability while navigating the generator’s air gaps, ensuring smooth progression of inspection tasks. Prof. Tam Hwa-yaw said, “PolyU is committed to promoting knowledge transfer and driving the translation of the University’s research outcomes into solid benefits for society. To enhance interdisciplinary learning, I founded the Engineering Entrepreneurship Club, offering undergraduate students the opportunity to participate in cutting-edge robotics research and the development of design solutions for industry, thereby cultivating their entrepreneurial spirit. Spanning approximately five years, this project combines PolyU’s research strength with CLP Power’s engineering expertise. Some team members have been involved since their freshman year, fully demonstrating the fruits of PolyU’s commitment to industry-academia-research collaboration and contributing to Hong Kong’s development into an international innovation and technology hub.” CLP Power Senior Director of Generation Mr Kevin Lau said, “CLP Power actively integrates innovative technologies into the daily operations of power stations and encourages our engineering teams to adopt innovative approaches to enhance operational practices. The generator inspection robot jointly developed with PolyU helps to enhance inspection efficiency and operational safety while supporting the development of more forward-looking maintenance strategies. In the long run, this strengthens the reliable operation of power generation facilities and supports the delivery of a safe and reliable electricity supply to the community. The project has also enabled CLP Power’s engineering teams to participate in the research, development and application of innovative solutions, further deepening collaboration with academia and nurturing Hong Kong’s innovation and technology talent.” The robot can cross the ventilation baffles inside air gaps to conduct three major inspection tasks—visual checks of ventilation ducts, assessing the insulation condition of stator core laminations, and conducting wedge tightness inspections through tapping. The PolyU research team and the CLP Power engineering team tested the application of the “Generator Inspection Robot” at the Black Point Power Station. ***END***

PolyU-developed, Hong Kong’s first LEO communication–navigation integrated satellite payload successfully launched, powering smart city and low-altitude economy development

The Hong Kong Polytechnic University (PolyU) has long been deeply and successfully engaged in the field of space technology. The University’s Department of Aeronautical and Aviation Engineering has developed Hong Kong’s first low-Earth-orbit (LEO) communication-navigation integrated satellite payload “LEO CNAV”, which was recently successfully launched aboard the Yuxing-3 No. 05 satellite (also known as “Tech-Innovation-1”) from the Jiuquan Satellite Launch Centre in Gansu. The launch of the satellite payload, which will undergo in-orbit testing, marks a historic milestone for PolyU in satellite technology and space applications. This year marks the first year of the Nation’s “15th Five-Year Plan”. The country is accelerating the cultivation of new quality productive forces through innovation and technology, creating vast growth potential for aerospace technology and related industries. The Government of the Hong Kong Special Administrative Region is also actively promoting aerospace science and technology development and supporting the space economy. This communication-navigation integrated breakthrough by PolyU highlights Hong Kong’s leading position in home-grown space technology and brings fresh momentum to the development of smart cities and the low-altitude economy. Dr WANG Tianqi, Research Assistant Professor of the Department of Aeronautical and Aviation Engineering and person-in-charge of system integration and testing, said, “From conceptual design and R&D testing to in-orbit operations, LEO CNAV has been developed entirely in-house by the PolyU team, opening a new chapter for independent satellite payload development by local universities. This experience has enabled our team to fully master the end-to-end payload development process, laying a solid foundation for the design of more advanced systems in the future.” LEO CNAV features four major technological advantages—functional integration, high-precision positioning, low-cost deployment and broad application potential—providing comprehensive support for future smart city infrastructure. In terms of functional integration, traditionally, communication and navigation rely on two separate systems operating independently. LEO CNAV removes this limitation by providing communication, navigation and timing services on a single platform. In future, users will only need one receiver to obtain both functions simultaneously, greatly simplifying system design. This breakthrough innovation has gained international recognition, being awarded a Gold Medal at the 51st International Exhibition of Inventions Geneva. The research team has also filed patent applications for the related core technologies. For positioning, LEO CNAV can be used in conjunction with existing Global Navigation Satellite Systems (GNSS) such as GPS to enhance positioning accuracy in dense urban environments with high-rise buildings. Traditional GPS satellites operate at an altitude of about 20,000 km, resulting in relatively weak signals that are vulnerable to interference or “spoofing attacks”, posing safety risks for autonomous driving and unmanned aerial vehicles. Operating in low Earth orbit at only a few hundred kilometres above ground, LEO CNAV provides much stronger signals. Combined with a uniquely designed signal scheme developed by the team, it effectively resists interference and spoofing, enabling highly accurate navigation for smart mobility and related applications. LEO CNAV is designed with commercial space needs in mind. The payload consumes only about 23 watts of power, which is less than the power drawn by a typical mobile phone charger, and is compact in size, making it suitable for nano-satellites and other small satellite platforms. Its modular design allows it to “ride-share” on various commercial satellites, requiring only about 30 watts of power and basic interfaces for deployment. By using commercial off-the-shelf components and hardware cost-control strategies, the team has significantly controlled launch costs, laying the groundwork for future large-scale constellation deployment. LEO CNAV represents a major breakthrough in positioning and navigation technologies and can be widely applied in smart city and low-altitude economy scenarios. Potential applications include enabling lane-level positioning for autonomous vehicles, providing precise navigation for UAV logistics and urban air mobility, and supporting urban infrastructure monitoring and emergency dispatch. LEO CNAV payload designer Prof. XU Bing, Assistant Professor of the Department of Aeronautical and Aviation Engineering, said, “Low-Earth-orbit navigation and integrated space–ground communication-navigation systems are the future direction for global space information infrastructure. Through the satellite technology accumulated from the LEO CNAV project, we hope in the longer term to support Internet of Things (IoT) interconnectivity and the deployment of integrated space–air–ground 6G networks, helping the Greater Bay Area build a world-class cluster of smart cities.” Looking ahead, the team plans to launch additional satellites carrying LEO CNAV to gradually build a LEO constellation network that will support the upgrading of smart transportation. Project leader Prof. WEN Chih-yung, Chair Professor of Aeronautical Engineering of the Department of Aeronautical and Aviation Engineering, said, “The successful launch of LEO CNAV marks a new chapter for PolyU. We will continue to advance innovation in space technology, nurture talent and broaden international collaboration, contributing to the development of Hong Kong’s commercial space sector and technological advancement in the Greater Bay Area.” In parallel with driving space research and development, PolyU is also committed to talent cultivation. This year, with a view to nurturing a new generation of professionals for the aerospace sector in Hong Kong and around the world, the University has launched Hong Kong’s first Master of Science in Satellite Engineering programme, covering areas such as satellite orbital dynamics, spacecraft systems, payload design and the emerging “New Space” economy.

PolyU supports 7 innovative research projects to advance campus-wide sustainability

The Hong Kong Polytechnic University (PolyU) is dedicated to translating its world-class research and innovations into practical solutions for pressing global challenges such as climate change. Under the Carbon Neutrality Funding Scheme 2025/26, 7 research projects have been awarded over HK$12.5 million collectively to support research that advances PolyU's carbon neutrality objectives. Through this initiative, the University continues to leverage its cross-disciplinary expertise to develop impactful technologies for climate mitigation and adaptation. PolyU launched the Carbon Neutrality Funding Scheme in 2022 to support the practical application of Carbon-neutrality research on the PolyU campus, with the Kowloon Tong Hostel Development (KTHD) included as a new testbed since the 2023 funding round. Funding proposals are assessed based on their potential to apply mature or emerging technologies on campus to reduce carbon emissions in practical ways, effectively address societal concerns, and deliver tangible University R&D outcomes. Each funded project may receive up to HK$2 million, inclusive of matching funds provided by the respective Faculty, School or Department, and may run for a maximum duration of 2 years. Carbon Neutrality Funding Scheme 2025/26 List of Awardees:

A New Era for Ultrafast Photonics: Two-Dimensional Mercury-Acetylide Frameworks for Near-Infrared Nonlinear Optics

In the increasingly digital world, the demand for faster, more efficient and miniaturised optical devices is ever-growing. From high-speed internet and secure quantum communications to advanced medical imaging and precision manufacturing, the backbone of these technologies is light, specifically how we can control and manipulate it at the nanoscale. Two-dimensional (2D) materials have emerged as a game-changer in this arena, offering unique properties that can be harnessed for ultrafast photonics and nonlinear optical applications.  However, the search for materials that combine stability, tunability and high performance in the near-infrared (NIR) region, a crucial window for telecommunications and sensing, remains a significant challenge. Prof. Yuen Hong TSANG, Associate Head and Professor of the Department of Applied Physics at The Hong Kong Polytechnic University (PolyU), and his research team introduce a new class of 2D quantum materials, the mercury(II)-acetylide frameworks (Hg–H2TPP), which not only overcome many of the limitations of existing materials but also open up exciting possibilities for switchable nonlinear optics and ultrafast laser technologies. By integrating heavy mercury(II) ions into a porphyrin-containing graphdiyne framework, the team has developed a material with remarkable optical properties, including strong and tuneable nonlinear absorption, rapid carrier dynamics and the ability to function as both a saturable absorber and an optical limiter. These features are critical for the development of advanced photonic devices such as Q-switched and mode-locked lasers, which are essential for telecommunications, high-precision measurements and quantum information processing. The research was published in Carbon.  The study demonstrates that the newly synthesised Hg–H2TPP nanosheets possess a combination of properties highly desirable for advanced photonic applications. Most notably, the material exhibits both saturable absorption and reverse saturable absorption behaviours, with nonlinear absorption coefficients that can be tuned across a wide range. This switchable nonlinear response is crucial for enabling the material to function as both a saturable absorber and an optical limiter, depending on the incident light intensity.  This study marks a significant advance in the field of quantum materials and nonlinear optics. By engineering a D-π-A-structured 2D mercury(II)-acetylide framework, Prof. Tsang’s team has created a material that combines strong NIR absorption, tuneable nonlinear optical responses and ultrafast carrier dynamics, which are all essential ingredients for next-generation photonic devices.  The ability to switch between saturable and reverse saturable absorption, coupled with the successful demonstration of both mode-locked and Q-switched lasers, underscores the potential of Hg–H2TPP for applications ranging from telecommunications and quantum information processing to biomedical imaging and laser-based manufacturing.  The insights gained from this work not only advance our understanding of 2D quantum materials but also lay the groundwork for the development of practical, high-performance devices that will shape the future of quantum technology. Source: Innovation Digest