1. Polymer-Ligated Nanocrystals Enabled by Nonlinear Block Copolymers as Nanoreactors
Colloidal nanocrystals exhibit a wide range of size- and shape-dependent properties and have found application in myriad fields, including optics, electronics, mechanics, drug delivery and catalysis, to name but a few. Synthetic protocols that enable the simple and convenient production of colloidal nanocrystals with controlled size, shape and composition are therefore of key general importance. Current strategies include organic solution-phase synthesis, thermolysis of organometallic precursors, sol-gel processes, hydrothermal reactions and biomimetic and dendrimer templating. Often, however, these procedures require stringent experimental conditions, are difficult to generalize, or necessitate tedious multistep reactions and purification. Recently, linear amphiphilic block co-polymer micelles have been used as templates to synthesize functional nanocrystals, yet the thermodynamic instability of these micelles limits the scope of this approach. In our group, we have pioneered a general strategy for crafting a large variety of functional nanocrystals with precisely controlled dimensions, compositions and architectures by using nonlinear block copolymers as nanoreactors. This new class of co-polymers forms unimolecular micelles that are structurally stable, therefore overcoming the intrinsic instability of linear block co-polymer micelles. Our approach enables the facile synthesis of organic solvent- and water-soluble nearly monodisperse nanocrystals with desired composition and architecture, including core–shell and hollow nanostructures. We demonstrate the generality of our approach by describing, as examples, the synthesis of various sizes and architectures of metallic, ferroelectric, magnetic, semiconductor and luminescent colloidal nanocrystals.
Representative Publications since 2020
(3) S. Liang, M. Zhang, S. He, M. Tian, T. Lian, and Z. Lin, “Metal Halide Perovskite Nanorods with Tailored Dimensions, Compositions, and Stabilities”, Nat. Synth. (in press).
(2) S. Liang, S. He, M. Zhang, Y. Yan, T. Jin, T. Lian, and Z. Lin, “Tailoring Charge Separation at Meticulously Engineered Conjugated Polymer/Perovskite Quantum Dot Interface for Photocatalyzing Atom Transfer Radical Polymerization”, JACS, 144, 12901 (2022).
(1) Y. Liu, J. Wang, M. Zhang, H. Li, and Z. Lin, “Polymer-Ligated Nanocrystals Enabled by Non-Linear Block Copolymer Nanoreactors: Synthesis, Properties and Applications”, ACS Nano, 14, 12491 (2020)
2. Perovskite Solar Cells
The superior optoelectronic properties of organometal halide perovskite ABX3 (e.g., A+ = methylammonium (CH3NH3+), formamidinium (HC(NH2)2+), Cs, or their combination; B2+ = Pb2+ and/or Sn2+; X– = Cl,– Br– and/or I–) such as high absorption coefficient, long-distance exciton diffusion, and large charge carrier mobility shed new light on fabricating high-performance, low-cost, and stable perovskite solar cells (PSCs). The past two decades have witnessed remarkable advances in PSCs with their power conversion efficiency (PCE) leaping from 3.8% to a recently certified 25.7%. Nonetheless, owing to their ionic crystal nature, perovskites display various defect states that result in charge trapping, non-radiative recombination, and hysteresis in the current–voltage characteristics and ultimately reduce PCE and long-term durability of PSCs. In this project, we focus on perovskite absorber design and crystal growth, defect passivation, interface engineering, and the understanding on how these strategies enable control over charge carrier dynamics, which in turn lead to stable, high-efficiency PSCs.
Representative Publications since 2020
(3) M. Zhang and Z. Lin, “Monolithic Perovskite Solar Capacitor Enabled by Double-sided TiO2 Nanotube Arrays”, ACS Energy Lett., 7, 1260 (2022).
(2) B. Wang, H. Li, Q. Dai, M. Zhang, Z. Zou, J. L. Brédas, Z. Lin, “Robust Molecular Dipole-Enabled Defect Passivation and Control of Energy Level Alignment for High-Efficiency Perovskite Solar Cells”, Angew. Chem. Int. Ed., 60, 17664 (2021).
(1) M. Zhang, M. Ye, W. Wang, C. Ma, S. Wang, Q. Liu, T. Lian, J. Huang, and Z. Lin, “Synergistic Cascade Carrier Extraction via Dual Interfacial Positioning of Ambipolar Black Phosphorene for High-Efficiency Perovskite Solar Cells”, Adv. Mater. 32, 2000999 (2020).
3. Perovskite X-Ray Scintillators and Detectors
X-ray detectors that convert the energy of X-ray into visible luminescence signals (i.e., scintillators) or electrical charges (i.e., direct detectors) play a key role in diagnostic radiology, nuclear physics, and nondestructive detection. Metal halide perovskites have received substantial attention as the next generation X-ray detecting and imaging materials due to their high effective atomic number (Zeff) component, high light yield, fast decay time, high charge carrier mobility and long carrier diffusion length. Moreover, controllable crystallinity and morphology, easy fabrication and solution processability render the production of large-scale perovskite films and editable array patterns. Compared with conventional single-crystal scintillators, perovskites carry great advantages in assembling X-ray detectors with extreme low detection limit, high flexibility, nanosecond response, and high spatial resolution. The dimensionality, electronic properties of defect states, and device architecture have decisive influence on the performance of perovskite X-ray detectors. In this project, we will optimize the growth method and encapsulation strategy, design novel device architectures, and develop new perovskite materials for high-quality X-ray scintillators and detectors.
4. Electrocatalysis
With rapid increase of fossil fuels consumption and continuous growth of global energy demands, there are needs for highly efficient energy conversion devices. Electrochemical energy conversion devices, such as water splitting, electrochemical CO2 conversion, fuel cells, represent promising approaches due to their high theoretical conversion efficiency and low environmental impact, boding well as the alternatives to traditional chemical/energy conversions in automobile, stationary grids, portable electronics, and chemical production. However, the performance of these devices has to be substantially improved to enable large-scale practical applications, which greatly depend on the design of catalysts in these systems and the optimization of the corresponding catalytic processes. In this project, we explore the following directions:
(a) Precise Design of Atomic-Scale Electrocatalysts
The goal is to develop highly active and selective electrocatalysts that can transform general molecules in the atmosphere (e.g., H2O, CO2 and N2) to valuable renewable energy sources (e.g. H2, hydrocarbons, CO and NH3). We will design new electrocatalyst materials at the atomic-scale via laser-assisted strategy, atom doping, and confinement to increase the conversion efficiency and selectivity of chemical transformations. With the help of advanced characterization in conjunction with theoretical calculations, we seek to identify the catalytic trends and illustrate the underlying reaction mechanisms.
Representative Publications since 2020
(3) B. Wang, C. Wang, X. Yu, Y. Cao, L. Gao, C. Wu, Y. Yao, Z. Lin, Z. Zou, “General synthesis of high-entropy alloy and ceramic nanoparticles in nanoseconds”, Nat. Synth., 1, 138 (2022).
(2) Y. Yan, S. Liang, X. Wang, M. Zhang, S. Hao, X. Cui, Z. Li, Z. Lin, “Robust wrinkled MoS2/N-C bifunctional electrocatalysts interfaced with single Fe atoms for wearable zinc-air batteries”, PNAS, 118, e2110036118 (2021).
(1) Y. Harn, S. Liang, S. Liu, Y. Yan, Z. Wang, J. Jiang, J. Zhang, Q. Li, Y. He, Z. Li, L. Zhu, H. Cheng, and Z. Lin, “Tailoring Electrocatalytic Activity of in-situ Crafted Perovskite Oxide Nanocrystals via Precise Size and Dopant Control”, PNAS, 118, e2014086118 (2021).
(b) External Field Coupled Electrocatalysis
Electrocatalysis is a key technology to achieve efficient conversion between electrical and chemical energy in various sustainable energy storage and utilization devices. However, the actual overpotentials of many electrochemical reaction processes are much higher than the equilibrium overpotentials. In this context, developing new strategies to further reduce the overpotential is crucial to realizing efficient electrocatalytic processes. In this regard, external field coupled electrocatalysis offers many strategic advantages in reducing the overpotential that might be tricky to regulate in conventional electrochemical fields. We are exploring routes of coupling external field (e.g., photo, magnetic field, pressure, etc.) and electrocatalysis to promote the conversion of energy-related molecules, such as H2O, CO2 and N2, to value-added products.
Representative Publications since 2020
(2) Li, M. Liu, Z. Qu,Y. Yue, T. Mao, Y. Yan, S. Zhao, M. Liu, and Z. Lin, “Fe Single Atoms with Asymmetrically Coordinated Heteroatoms Scaffolded by Spoke-like Mesoporous Carbon Nanospheres for Robust Ring-opening Reaction”, PNAS, 120, e2218261120 (2023).
(1) L. Gao, X. Cui, Z. Wang, C. D. Sewell, Z. Li, S. Liang, M. Zhang, J. Li, Y. Hu, Z. Lin, “Operando Unraveling Photothermal-Promoted Dynamic Active Sites Generation in NiFe2O4 for Markedly Enhanced Oxygen Evolution”, PNAS, 118, e2023421118 (2021).
5. All Solid-State Li-ion Battery
Ever-increasing demand derived from the extremely rapid development of portable electronic and grid-scale energy storage have entailed continuous exploration of next-generation secondary batteries, among which advanced lithium-based batteries (e.g., lithium-sulfur and lithium-metal batteries) have garnered much attention. Therefore, the development of electrolytes for transporting lithium (i.e., lithium-conducting electrolytes) is of key importance. Notably, conventional liquid electrolytes suffer from several issues such as toxicity, volatility and flammability. Moreover, liquid electrolytes have inferior anti-oxidation abilities at high voltages. To this end, replacing liquid electrolytes with lithium-conducting polymer electrolytes (PEs) has been widely recognized as a promising route to alleviating the concerns noted above. Notably, although Bolloré Bluecar, the first electric vehicle equipped with solid polymer electrolytes (SPEs), already showcased in 2008, the low room temperature ionic conductivity still doesn’t satisfy the requirement for batteries. In this project, we will develop solid-state electrolytes (SSEs) with polymer frameworks, including SPEs and gel polymer electrolytes (GPEs). The flexibility, stretchability, and mechanical strength impart PEs with good processability, intimate contact with electrodes, and the ability to suppress lithium dendrite. Additionally, the development of PEs also afford a promising prospect for assembling flexible devices.
Representative Publications since 2020
(1) S. Hao, S. Liang, C. D. Sewell, Z. Li, C. Zhu, J. Xu, and Z. Lin, “Lithium-Conducting Branched Polymers: New Paradigm of Solid-State Electrolytes for Batteries”, Nano Lett., 21, 7435 (2021).
6. Photocatalysis for Clean Energy
Photocatalysis stands out as an effective strategy to achieve clean energy production and environmental remediation due to cost effectiveness and green, ecofriendly, and mild operating conditions. It has been widely implemented in CO2 conversion, H2 production via water splitting, biomass conversion, nitrogen fixation, and air and wastewater purification. In this context, the design and synthesis of robust photocatalysts is the key to efficient photocatalytic performance. However, the ability to regulate photocatalytic activity and selectivity represents the bottleneck of current research. In this project, we study the structure-activity relationship of photocatalysts via tailoring the structure of photocatalysts at atomic or nanoscopic scale, such as single-atom anchoring, design of core/shell nanostructure, heterostructure synthesis, defect regulation, etc.
7. Mechanically Robust Antifouling Coating Materials
Marine biofouling is induced by the accumulation of diverse marine organisms on equipment surfaces under seawater. It has numerous adverse impacts on maritime transportation as well as the development and utilization of marine resources. For example, marine biofouling increases a ship’s sailing resistance, fuel consumption, and carbon dioxide emissions. To combat marine biofouling, the most convenient, economical, and widely used approach is to develop anti-biofouling coatings including silyl, copper, or zinc acrylate-based self-polishing coatings, fouling release coatings, self-generated hydrogels, slippery liquid-infused surfaces, zwitterionic polymers, amphiphilic polymers, and antibacterial. However, these coating materials often show too soft characteristics and weak interactions between antifoulant and polymer carrier. Moreover, it remains a great challenge to create coating materials with robust mechanical properties and controllable hydrolysis/antifoulant release rate. In addition, conventional coatings are based on non-degradable polymers, leading to significant threats to the marine environment. In this project, we resolve these issues via developing a general strategy by crafting a series of degradable polymers-based antifouling coatings with robust mechanical properties, high antifoulant loading, controllable antifoulant release, and environmental benignity. Such coating materials will be rendered by constructing bio-mimic aberration-resistant surface microstructure, tuning the ratio between polymer repeat units bearing different functional groups, and utilizing degradable polymer backbones.
Representative Publications since 2020
(1) W. Zheng, J. Huang, X. Zang, X. Xu, W. Cai, Z. Lin and Y. Lai, “Judicious Design and Rapid Manufacturing of Flexible, Mechanically Resistant Liquid-like Coating with Strong Bonding and Antifouling Abilities”, Adv. Mater., 34, 2204581 (2022)