Research
Mission Statement
We study the fascinating molecular assembly processes, such as nucleation, crystal growth, aggregation, etc, which critically impact the solid-state properties of materials (e.g. thermodynamic, kinetic, electronic, optical, mechanical). We are particularly interested in the highly non-equilibrium molecular assembly processes during additive manufacturing of soft functional materials. It is our goal to control the solid-state properties by understanding the fundamental molecular assembly processes, and ultimately, to achieve additive manufacturing for a future of cleaner environment and greener energy.
Research Themes
The hierarchical assembly of conjugated polymers has gained much attention due to its critical role in determining the optical/electrical/mechanical properties. The hierarchical morphology encompasses molecular scale intramolecular conformation (torsion angle, chain folds) and intermolecular ordering (π-π stacking), mesoscale domain size, orientation and connectivity, and macroscale alignment and (para)crystallinity. Such complex morphology in the solid state is fully determined by the polymer assembly pathway in the solution state, which in turn is sensitively modulated by molecular structure and processing conditions. However, molecular pictures of polymer assembly pathways remain elusive to date. We leverage a wide range of in situ and ex situ structural characterization techniques to elucidate the journey of conjugated polymer assembly from solution to the solid state, under near and far-from-equilibrium conditions.
Recent years, we have focused on understanding chiral liquid crystal mediated assembly of achiral conjugated polymers, a phenomenon we discovered by serendipity. Intimately connected to the rule of life, chirality remains a long-time fascination in biology, chemistry, physics and materials science. When applied to functional polymers, chirality may give rise to intriguing optical, electronic, and biological properties unimagined before. In addition, we are also interested in understanding pre-aggregation mediated assembly pathway of organic solar cells, which sensitively modulate the power conversion efficiency. We are working to unravel how molecular structures define pre-aggregates formation, their hierarchical structures and the ultimate device performance. This work has been highlighted on Illinois News Bureau.
Key papers
[1] Rui Sun#, Kyung Sun Park#, Andrew Comstock, Aeron McConnell, Yen-Chi Chen, David Beratan, Wei You, Axel Hoffmann, Zhi-Gang Yu, Ying Diao*, Dali Sun* “Inverse Chirality-Induced Spin Selectivity Effect in Chiral Assemblies of π-Conjugated Polymers”, Nature Materials, 2024, 23, 782-789. DOI: https://doi.org/10.1038/s41563-024-01838-8.
** Highlighted by NCSU News, EurekAlert!, Phys.org, etc. “Printed polymer allows researchers to explore chirality and spin interactions at room temperature” 03/15/2024
[2] Kyung Sun Park, Xuyi Luo, Justin J. Kwok, Azzaya Khasbaatar, Jianguo Mei and Ying Diao, “Subtle molecular changes largely modulate chiral helical assemblies of achiral conjugated polymers by tuning solution-state aggregation”, ACS Central Science, 2023, 9, 11, 2096–2107, DOI: 10.1021/acscentsci.3c00775
** Featured by University of Illinois, EurekAlert!, ScienceDaily, Phys.Org, Materials Today, etc.
“Researchers identify unexpected twist while developing new polymer-based semiconductors”, 11/14/2023
[3] Khasbaatar, Azzaya*; Xu, Zhuang*; Lee, Jong-Hoon*; Campillo-Alvarado, Gonzalo; Hwang, Changhyun; Onusaitis N., Brandon(undergrad); Diao, Ying*, “From Solution to Thin Film: Assembly of π-Conjugated Systems and Impact on Device Properties of Organic Electronics and Photovoltaics”, Chemical Reviews, 2023, 123, 13, 8395–8487. DOI: 10.1021/acs.chemrev.2c00905
** Invited for Chemical Review Thematic Issue – Emerging Materials for Optoelectronics
[4] Xu, Z.; Park, K.S.; Kwok, J.J.; Lin, O.; Patel, B.B.; Kafle, P.; Davies, D.W.; Chen, Q.; Diao, Y. “Not all aggregates are made the same: Distinct structures of solution aggregates drastically modulate assembly pathways, morphology and electronic properties of conjugated polymers”. Advanced Materials, 2022, 34, 2203055. https://doi.org/10.1002/adma.202203055
** Invited for the “Rising Stars” Series
[5] Park, K.S.; Xue, Z.; Patel, B.B.; An, H.; Kwok, J. J.; Kafle, P.; Chen, Q.; Shukla, D.; Diao, Y. “Chiral Emergence in Multistep Hierarchical Assembly of Achiral Conjugated Polymers”. Nature Communications, 2022, 13, 2738, DOI: 10.1038/s41467-022-30420-6
** Highlighted by Beckman Institute, EurekAlert!, ScienceDaily etc.
“Power up: New polymer property could boost accessible solar power”, 06/02/2022
[6] Kwok, J. J.; Park, K. S.; Patel, B. B.; Dilmurat, R.; Beljonne, D.; Zuo, X.; Lee, B.; Diao, Y. “Understanding Solution State Conformation and Aggregate Structure of Conjugated Polymers via Small Angle X-ray Scattering”. Macromolecules, 2022, 55, 11, 4353–4366. DOI:10.1021/acs.macromol.1c02449
[7] Park, K.S.*; Kwok J.J.*; Kafle, P.*; Diao, Y. “When Assembly Meets Processing: Tuning Multiscale Morphology of Printed Conjugated Polymers for Controlled Charge Transport”, Chemistry of Materials, 2021, 33, 469–498, https://doi.org/10.1021/acs.chemmater.0c04152
** Invited perspective for the “Up and Coming” series
[8] Park, K. S.*; Kwok, J.J.*; Dilmurat, R.; Qu, G.; Kafle, P.; Luo, X.; Olivier, Y.; Lee, J.-K.; Mei, J.; Beljone, D.; Diao, Y. “Tuning Conformation, Assembly and Charge Transport Properties of Conjugated Polymers by Printing Flow”, Science Advances, 2019, 5, 8, eaaw7757. DOI: 10.1126/sciadv.aaw7757
**Highlighted on Illinois homepage, EurekAlert!, Science Daily, Phys.org, the Engineer etc.
“Printing flattens polymers, improving electrical and optical properties” 08/09/2019
[9] Mohammadi, E.; Zhao, C.; Meng Y.; Zhang, F.; Qu, G.; Mei, J.; Zuo, J.-M.; Shukla, D.; Diao, Y. “Dynamic-Template-Directed Multiscale Assembly for Large-Area Coating of Highly-Aligned Conjugated Polymer Thin Films”. Nature Communications. 2017, 8, 16070. DOI:10.1038/ncomms16070
**Highlighted on Illinois homepage, Science Magazine, EurekAlert!, R&D magazine, Phys.org, etc.
“Researchers develop dynamic templates critical to printable electronics technology” 07/13/2017
[10] Qu, G.; Kwok, J.J.; Diao, Y. “Flow-Directed Crystallization for Printed Electronics”. Account of Chemical Research (Invited). 2016, 49, 2756-2764. DOI: 10.1021/acs.accounts.6b00445
3D printing (additive manufacturing) technologies have achieved widespread commercialization for melt extrusion of thermoplastic structural polymers (a.k.a. fused deposition modeling), thanks to their low cost, reliability, and ease of use. Expanding the material palette to functional materials is a revolutionary next step that has been recently reported for cell-laden gels, electronic materials, and even pharmaceutical drugs, although the overwhelming focus has been on determining suitable ink formulations for material delivery, with less attention paid toward the molecular assembly process during deposition. Integrating molecular assembly with 3D printing offers a compelling avenue to attaining structural control down to the nanoscopic and molecular scale. Such precision of structural control has been challenging with current 3D printing approaches. In collaboration with Guironnet, Sing and Rogers groups, we leverage nanoscale assembly of bottle-brush block co-polymers for 3D printing of structure color. By custom design of an integrated hardware/software platform, we aim to dynamically modulate printed structures at the nanoscale to program the structure color as we print without changing the ink material. We tap into our expertise of polymer assembly to precisely control the kinetics of microphase separation during printing, which is key to dynamic modulation of structure color. This work has been highlighted on Illinois News Bureau.
Key papers
[1] Jeon, S. †; Kable, Y. L. †; Kang, H. †; Shi, J. †; Wade, M. A.; Patel, B. B.; Pan, T.; Rogers, S. A.*; Sing, C. E.*; Guironnet, D.*; Diao, Y*. “Direct-Ink-Write Crosslinkable Bottlebrush Block Polymers for On-the-fly Control of Structural color”, Proceedings of the National Academy of Sciences, 2024, 121 (9), e2313617121. DOI: 10.1073/pnas.2313617121.
** Highlighted on PNAS front cover.
** Highlighted by Chemical & Engineering News
“Printable polymer with tunable structural color” 02/26/2024
** Highlighted by Forbes Magazine.
“Multi-Color Printing With Just One Ink Opens The Door To New Materials” 02/20/2024
** Highlighted by Beckman Institute, EurekAlert!, Phys.org, etc.
“Chameleons inspire new multicolor 3D-printing technology” 02/19/2024
** Featured on NAE Frontiers of Engineering homepage, 05/20/2024
[2] Patel, B.B.; Walsh, D.J.; Kim, D.H. (undergraduate); Kwok J.J.; Lee, B.; Guironnet, D.; Diao, Y. “Tunable Structural Color of Bottlebrush Block Copolymers through Direct-Write 3D Printing from Solution”, Science Advances, 2020, 6, eaaz7202. DOI: 10.1126/sciadv.aaz7202
**Highlighted on Illinois Homepage, EurekAlert!, Phys.org, ScienceDaily etc.
“Researchers mimic nature for fast, colorful 3D printing” 06/10/2020
** Highlighted on Science Advances front page as an online rotator featuring paper
“3D printing structure color – a custom designed 3D printing platform tunes structure color” 06/12/2020
**Featured on the front page of the Advanced Photon Source of Argonne National Lab as a Science Highlight. “Mimicking Nature for Fast, Colorful 3-D Printing” 06/17/2020
[3] Patel, B.B.; Pan, T.; Chang, C. (undergraduate); Walsh, D.J; Kwok, J.J.; Park. K.S.; Patel, K. (undergraduate); Guironnet G.; Sing, C.E.; Diao, Y., “Concentration-Driven Self-Assembly of PS-b-PLA Bottle-brush Diblock Copolymers in Solution”. ACS Polymers Au, 2022, 2, 232–244. https://doi.org/10.1021/acspolymersau.1c00057
** Selected to be featured as an ACS Editors’ Choice Article
** Listed among “most read articles” of the journal
** Invited Front Cover
In order to meet the food requirement of nutrient and safety for astronauts in long space missions, it is important for researchers to develop a way of cultivating fresh green vegetables in space. Great progress has been made to achieve plant growth in space in previous works by NASA, including plant growing payload such as Advanced Plant Habitat (APH) and the Vegetable Production System (Veggie). These units require substantial human effort to maintain and optimize and do not afford detection of plant growth and health condition remotely and autonomously. Moreover, simple inspection is insufficient for identifying the specific stress a plant is enduring, especially at the early stage. To address these challenges, we are developing light-weight, flexible and stretchable organic-electronics based chemical and strain sensors for autonomous, remote monitoring of plant health and plant growth. The potential impact of our approach goes beyond cultivating vegetables for plants. Our technology could contribute to understanding how plants cope with climate change, and to enhancing crop productivity for feeding the growing human population. Read more about this project in LAS News.
Related Papers
[1] Wang S., Diao Y*., “Printed Electronics for Cultivating Plants in Space”, Nature Reviews Materials, 2024, DOI: 10.1038/s41578-024-00742-6.
[2] Wang, S.; Edupulapati, B (undergrad).; Hagel, J. (undergrad); Kwok, J.; Quebedeaux, J.C.; Khasbaatar, A.; Daviel, D.W.; Ella Elangovan K.; Leakey, A.D.B.; Hill, C.W.; Varnavas, K.A.; Diao, Y., “Highly stretchable wearable electronics for remote, autonomous plant growth monitoring“, Device, 2024, 2, 100322. DOI: 10.1016/j.device.2024100322.
** Highlighted on Device front cover.
** Highlighted by IlliniNews, SpaceDaily, DailyIllini, etc.
“Revolutionizing plant growth: UI scientists leap toward outer-space farming” 03/24/2024
“Study brings scientists a step closer to successfully growing plants in space” 03/14/2024
**Highlighted by Astronomy
“It’s hard to grow food in space. These sensors can help” 04/01/2024
Organic photovoltaics (OPV) are next-generation devices for harvesting renewable energy that are becomingly increasingly desired over traditional silicon solar cells. The two primary challenges preventing the widespread adoption of OPV relative to silicon-based solar cells are inferior power conversion efficiency and apparent instability to sunlight. Working with synthetic chemists and computer scientists, we aim to develop new machine learning tools to guide the discovery of highly efficient and indefinitely stable organic photovoltaics via automated synthesis, manufacture, and testing at the device level. Check out the Molecule Maker Lab Institute for more.
[1] Nicholas H. Angello†, David M. Friday†, Changhyun Hwang†, Seungjoo Yi†, Austin Cheng^, Tiara Torres Flores^, Wesley Wang, Edward R. Jira, Alán Aspuru-Guzik*, Martin D. Burke*, Charles M. Schroeder*, Ying Diao*, Nicholas E. Jackson*, “Closed-Loop Transfer Enables AI to Yield Chemical Knowledge”, Nature, 2024, 633, 351–358. DOI: 10.1038/s41586-024-07892-1
We are deciphering the molecular origin of cooperativity in structural transitions, a phenomenon long used by living systems for circumventing energetic and entropic barriers to yield highly efficient molecular processes. Ultrafast, reversible cooperative transitions give rise to the shape memory effect, which is widely applied to designing medical devices, drug delivery vehicles, actuators and sensors in the automotive and aerospace industry. Surprisingly, cooperative transitions are rarely studied in molecular crystals, and thus its molecular mechanism remains unclear. Combining in situ polarized microscopy, single crystal X-ray diffraction, Raman spectroscopy and solid-state NMR, we are working to discover the molecular design rules of cooperative transitions in electronic crystals triggered by thermal, mechanical energy and light. We are also applying cooperative transitions to realize shape memory electronics and superelastic, strain-resilient single crystal electronic devices. This work has been highlighted on Illinois News Bureau and Beckman Institute.
Key papers
[1] Davies, D.W.*; Seo, B.*; Park, S.K.; Shiring, S.B.; Chung, H.; Kafle, P.; Yuan, D.; Strzalka, J.W.; Weber, R.; Zhu, X.; Savoie, B.M.*; Diao, Y.* “A Tale of Two Transitions: Unraveling Two Distinct Polymorph Transition Mechanisms in One n-Type Single Crystal for Dynamic Electronics”. Nature Communications, 2023, 14, 1304. DOI:10.1038/s41467-023-36871-9
** Featured by Beckman Insititute, EurekAlert!, Science Daily, Nanowerk et al.
“Molecular teamwork makes the organic dream work”, March 21st, 2023
[2] Park, S.K.; Diao, Y. “Martensitic Transition in Molecular Crystals for Dynamic Functional Materials”, Chemical Society Reviews,2020, 49, 8287-8314, https://doi.org/10.1039/D0CS00638F (invited for the “2020 Emerging Investigator Issue”).
** Invited review for the “2020 Emerging Investigator Issue”
[3] Park, S.K.*; Sun, H.*; Chung, H.; Patel, B.B.; Zhang, F.; Davies, D.W.; Woods, T.J.L; Zhao, K.*; Diao, Y.* “Super- and Ferro-elastic Organic Semiconductors for Ultraflexible Single Crystal Electronics”, Angewandte Chemie International Edition, 2020, 59, 2-11. https://doi.org/10.1002/anie.202004083
** Selected as a “Hot paper” by the Angewandte Chemie editors
**Highlighted by Beckman Institute News, EurekAlert!, Science Daily, Phys.org, etc.
“Designing flexible and stretchable single crystal electronic systems” 05/13/2020
**Featured by Materials Today, “Organic crystal could stretch to electronics applications” 05/26/2020
[4] Chung, H.; Dudenko, D.; Zhang, F.; D’Avino, G.; Ruzie, C.; Richard, A.; Schweicher, G.; Beljonne, D.; Geerts, Y.H.; Diao, Y.“Rotator Side Chains Trigger Cooperative Transition for Shape and Function Memory Effect in Organic Semiconductors”. Nature Communications. 2018, 9, 278. DOI:10.1038/s41467-017-02607-9
**Highlighted on Illinois homepage, EurekAlert!, Science Daily, R&D magazine, Phys.org, etc.
“Shape-shifting organic crystals use memory to improve plastic electronics” 01/25/2018
**Top 50 most read Nature Communications physics articles published in 2018
Core Values
We strive to become first-rate scholars and inventors, who carry out impactful, rigorous research that stands the test of time.
We define excellent scholarship in terms of
– the passion, drive and capability to solve scientific problems
– inquisition or inventiveness
– mastery of fundamentals
– mastery of literature
– critical thinking skills, rigor and attention to details
– analytical skills: the ability to uncover hidden trends in data and the ability to model them
– the ability to clearly and compellingly communicate results, in both oral and written forms
“There is no satisfactory substitute for excellence.”
– Dr. Arnold O. Beckman
It is our ultimate goal to serve our communities by creating new knowledge and new technologies for solving the grand challenges of our society.
There is absolutely no compromise in integrity. It is foundational to everything we do.
Attaining excellence in research is no easy task. Since we aim high (carrying out original research rather than derived research), the journey can be full of pitfalls, distress and hardship. Grit is the hard work, perseverance, dedication and sustained passion that you need to pull yourself through this challenging journey.
For more on grit, check out this illuminating TED talk:
We embrace different cultures, diverse life experience, expertise and viewpoints. We are open to new challenges and are willing to go out of our comfort zones.
We strive to build a collaborative group culture where we are genuinely interested in helping each other, contribute to each other’s research, invest in each other’s success and help each other achieve the best version of oneself.