Current Research Projects:


1. A General and Robust Strategy for Monodisperse Functional Nanocrystals (i.e., Plain, Core/Shell, Hollow and Janus Nanocrystals)



Colloidal nanocrystals exhibit a wide range of size- and shapedependent properties and have found application in myriad fields, incuding 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, but the thermodynamic instability of these micelles limits the scope of this approach. We have been developing a general strategy for crafting a large variety of functional nanocrystals with precisely controlled dimensions, compositions and architectures by using star-like 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.


Selected Publications:

3. D. Zheng, X. Pang, M. Wang, Y. He, C. Lin, and Z. Lin*, "An unconventional route to hairy plasmonic/semiconductor core/shell nanoparticles with precisely controlled dimensions and their use in solar energy conversion”, Chemistry of Materials. 27, 5271 (2015).

2. H. Xu, Y. Xu, X. Pang, Y. He, J. Jung, H. Xia, and Z. Lin*, "A general route to nanocrystal kebabs periodically assembled on stretched flexible polymer shish”, Science Advances. 1, e1500025 (2015).

1. X. Pang, L. Zhao, W. Han, X. Xin, and Z. Lin*, "A general and robust strategy for the synthesis of nearly monodisperse colloidal nanocrystals”, Nature Nanotechnology, 8, 426 (2013).

 

2. Materials for Solar Energy Conversion


Perovskite Solar Cells



Perovskite is named after Russian mineralogist Perovskite who first characterized the crystal structure of ABX3-type (X=halogen, oxygen; e.g., CaTiO3) inorganics. The superior optoelectronic properties of organometal halide perovskite CH3NH3PbX3 (X=halogen) 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 solar cells. In this project, we focus on developing new perovskite photovoltaic materials, engineering device architectures of perovskite-based solar cells, and exploring photophycial mechanisms of perovskite-based solar cells, thereby leading to high-efficiency solar cells.


Selected Publications:

2. M. He, X. Pang, X. Liu, B. Jiang, Y. He, H. Snaith, and Z. Lin*, "Monodisperse Dual-Functional Upconversion Nanoparticles-Enabled Near-Infrared Organolead Halide Perovskite Solar Cells”, Angewandte Chemie International Edition. (accepted)

1. M. He, D. Zheng, M. Wang, C. Lin, and Z. Lin*, "High efficiency perovskite solar cells: from complex nanostructure to planar heterojunction”, Journal of Materials Chemistry A, 2, 5994 (2014).(Invited Feature Article) (featured on Cover of Journal of Materials Chemistry A).

 

Dye-Sensitized Solar Cells



Dye-sensitized solar cells (DSSC) are widely recognized as a promising alternative to conventional silicon solar cells, which usually suffer from a high cost of manufacturing and installation. A great deal of research efforts have been made in DSSCs to achieve improved performance, including the rational design and exploitation of a wide diversity of dyes as light absorbers, the optimization of nanocrystalline TiO2 photoanodes of different architectures for dye loading and electron transport, the utilization of redox electrolytes with effective components for hole transport, and the replacement of expensive noble metal films (e.g., platinum) with other low-cost materials to serve as back-contact electrodes. In this project, we capitalize on hierarchically structured nanotubes and nanoflowers as photoanodes to yield high efficiency DSSCs, which can be attributed primarily to the synergistic effect of higher dye loading due to the presence of large surface area, superior light scattering ability, and fast charge transport.


Selected Publications:

9. M. Ye, X. Wen, M. Wang, J. Iocozzia, N. Zhang, C. Lin, and Z. Lin*, "Recent advances in dye-sensitized solar cells: from photoanodes, sensitizers, electrolytes to counter electrodes”, Materials Today. 18, 155 (2015).

8. M. Ye, D. Zheng, M. Lv, C. Chen, C. Lin, and Z. Lin*, "Hierarchically structured nanotubes for highly efficient dye-sensitized solar cells”, Advanced Materials , 25, 3039 (2013) (featured on the Frontispiece of Advanced Materials)

7. M. Ye, H. Liu, C. Lin, and Z. Lin*,Hierarchical rutile TiO2 flower clusters based high efficiency dye-sensitized solar cells via direct hydrothermal growth on conducting substrates”, Small, 9, 312 (2013).

6. J. Wang and Z. Lin*,Dye-sensitized TiO2 nanotube solar cells: rational structural and surface engineering on TiO2 nanotubes”, Chem. Asian J., 7, 2754 (2012) (Invited Focus Review).

5. Y. H. Jang, X. Xin, M. Byun, Y. Jang, Z. Lin*, and D. H. Kim*, “An unconventional route to high efficiency dye-sensitized solar cells via embedding graphitic thin films into TiO2 nanoparticle photoanode”, Nano Lett., 12, 479 (2012).

4. X. Xin, J. Wang, W. Han, M. Ye, and Z. Lin*, “Dye-sensitized solar cells based on a nanoparticle/nanotube bilayer structure and their equivalent circuit analysis”, Nanoscale, 4, 964 (2012).

3. M. Ye, X. Xin, C. Lin, and Z. Lin*, "High efficiency dye-sensitized solar cells based on hierarchically structured nanotubes”, Nano Lett., 11, 3214 (2011).

2. J. Wang and Z. Lin*, "Dye sensitized TiO2 nanotube solar cell with markedly enhanced performance via rational surface engineering", Chem. Mater., 22, 579 (2010). (Featured on the Cover of Chem. Mater.).

1. J. Wang and Z. Lin*, "Freestanding TiO2 nanotube arrays with ultrahigh aspect ratio via electrochemical anodization", Chem. Mater., 20, 1257 (2008).

Organic-Inorganic Nanocomposites by Placing Conjugated Polymers in Intimate Contact with Quantum Dots (Rods) and Their Use in Hybrid Solar Cells



Placing conjugated polymers (CPs) in direct contact with quantum dots (QDs) (or quantum rods; QRs) offers advantages over cases where QD (QR) aggregation dominates. Such quantum dot (rod)-conjugated polymer nanocomposites (i.e., CP-QD (QR)) possess a well-defined interface, thereby significantly promoting the charge (or energy) transfer between these two components. In this project, we craft CP-QD (QR) nanocomposites based on rational designs, explore their photophysical properties, and exploit these intimate organic-inorganic nanocomposites for use in organic-inorganic hybrid solar cells with improved power conversion efficiency.


Selected Publications:

5. M. He, F. Qiu, and Z. Lin*, "Towards high performance organic-inorganic hybrid solar cells: bringing conjugated polymers and inorganic nanocrystals in close contact”, The Journal of Physical Chemistry Letters, 4, 1788 (2013). (featured on the Cover of The Journal of Physical Chemistry Letters).

4. L. Zhao and Z. Lin*, “Crafting semiconductor organic-inorganic nanocomposites via placing conjugated polymers in intimate contact with nanocrystals for hybrid solar cells”, Advanced Materials, 24, 4353 (2012). (Invited Review) (featured on Inside Front Cover of Advanced Materials).

3. L. Zhao, X. Pang, R. Adhikary, J. Petrich, M. Jeffries-EL, and Z. Lin*, "Organic-inorganic nanocomposites by placing conjugated polymers in intimate contact with quantum rods”, Advanced Materials, 23, 2844 (2011). (featured on Frontispiece of Advanced Materials (July 5 issue)).

2. L. Zhao, X. Pang, R. Adhikary, J. Petrich, and Z. Lin*, "Semiconductor anisotropic nanocomposites via directly coupling conjugated polymers with quantum rods”, Angewandte Chemie International Edition, 50, 3958 (2011). (Featured on Inside Front Coverof Angewandte Chemie International Edition; Featured on Nanowerk; highlighted by MRS Bulletin(the June 2011 issue (Vol 36, PP 405))).

1. J. Xu, J. Wang, M. Mitchell, P. Mukherjee, M. Jeffries-EL, J. W. Petrich, and Z. Lin*, "Organic-inorganic nanocomposites prepared by grafting conjugated polymers onto quantum dots", Journal of the American Chemical Society, 129, 12828 (2007).


Quantum Dot-Sensitized Solar Cells



Quantum dot-sensitized solar cells (QDSSCs) have emerged as a promising solar architecture for next-generation solar cells. The QDSSCs exhibit a remarkably fast electron transfer from the quantum dot (QD) donor to the TiO2 acceptor with size quantization properties of QDs that allows for the modulation of band energies to control photoresponse and photoconversion efficiency of solar cells. To understand the mechanisms that underpin this rapid charge transfer, the electronic properties of CdSe and PbSe QDs with different sizes on the TiO2 substrate are simulated using a rigorous ab initio density functional method. This method capitalizes on localized orbital basis set, which is computationally less intensive. Quite intriguingly, a remarkable set of electron bridging states between QDs and TiO 2 occurring via the strong bonding between the conduction bands of QDs and TiO2 is revealed. Such bridging states account for the fast adiabatic charge transfer from the QD donor to the TiO2 acceptor, and may be a general feature for strongly coupled donor/acceptor systems. All the QDs/TiO2 systems exhibit type II band alignments, with conduction band offsets that increase with the decrease in QD size. This facilitates the charge transfer from QDs donors to TiO2 acceptors and explains the dependence of the increased charge transfer rate with the decreased QD size.


Selected Publications:

1. X. Xin, R. Biswas, B. Li, J. Jung, Y. Yoon, and Z. Lin*, "Ab initio simulation of charge transfer at the semiconductor quantum dot/TiO2 interface in quantum dot-sensitized solar cells”, Particle and Particle Systems Characterization, 32, 80 (2015). (featured on Cover of Particle and Particle Systems Characterization).


Polymer Solar Cells



The synthesis and self-assembly of rod-rod diblock copolymers that possess both intriguing nanostructures and electronic activities provide expanded opportunities for developing high-performance bulk heterojunction (BHJ) solar cells. In this project, we explore the molecular organization of a new class of all-conjugated diblock copolymers, poly(3-butylthiophene)-b-poly(3-hexylthiophene) (P3BHT) chains (i.e., the packing of interchains) and the nanoscale morphology of the resulting P3BHT/PC71BM thin blend films, which can be precisely controlled by tailoring the molar ratio of P3BT and P3HT blocks in P3BHT, thereby leading to solar cells with improved performance.


Selected Publications:

3. M. He, F. Qiu, and Z. Lin*, "Conjugated rod-coil and rod-rod block copolymers for photovoltaic applications”, Journal of Materials Chemistry, 21, 17039 (2011). (Invited Feature Article) (featured on the Front Cover of Journal of Materials Chemistry).

2. M. He, W. Han, J. Ge, Y. L. Yang, F. Qiu, and Z. Lin*, "High efficiency all-conjugated poly(3-alkylthiophene) diblock copolymer-based bulk heterojunction solar cells with controlled molecular organization and nanoscale morphology", Energy Environ. Sci., 4, 2894 (2011).

1. M. He, L. Zhao, J. Wang, W. Han, Y. L. Yang, F. Qiu, and Z. Lin*, "Self-assembly of all-conjugated poly(3-alkylthiophene) diblock copolymer nanostructures from mixed selective solvents", ACS Nano, 4, 3241 (2010). (Featured as an In Nano selection).



3. Materials for Energy Storage (Li-ion Batteries)



Nowadays, industrial and transportation activities consume a large amount of fossil fuels. The imminent shortage of fossil fuels and growing environmental concern are pushing scientists and engineers to exploit sustainable, clean, and highly efficient technologies to supply and store energy. Due to their relatively high energy density, good cycle life and good power performance, lithium ion batteries (LIBs) are the most popular rechargeable batteries. In addition to their applications in electric and hybrid electric vehicles, LIBs have become the power source for a myriad of portable electronic devices, which have revolutionized society during the last decades. Efficient electrode materials are the hard core for the performance improvement of lithium ion battery. In this project, we focus on the design and fabrication of nanostructured metal oxides and oxysalts as anode materials for high performance LIBs, such as Zn2GeO4, CuGeO3, ZnFe2O4, SnO, TiO2, Fe2O3, MnO2, Co3O4, etc.


Selected Publications:

6. B. Jiang, C. Han, B. Li, Y. He, and Z. Lin*, "In-situ Crafting of ZnFe2O4 Nanoparticles Impregnated within Continuous Carbon Network as Advanced Anode Materials”, ACS Nano. (in press)

5. C. Wang, L. Tang, Y. He,* S. Wang, L. Gan, J. Li, H. Du, B. Li, Z. Lin*, and F. Kang* "A robust strategy for crafting monodisperse Li4Ti5O12 nanospheres as superior rate anode for lithium ion batteries”, Nano Energy. (accepted)

4. S. Wu, R. Xu, M. Lu, R. Ge, J. Iocozzia, C. Han, B. Jiang, and Z. Lin*, "Graphene-Containing Nanomaterials for Lithium Ion Battery”, Advanced Energy Materials. 5, 1500400 (2015).

3. C. Han, D. Yang, Y. Yang, B. Jiang, Y. He, M. Wang, A. Song, Y. He, B. Li, and Z. Lin*, "Hollow Titanium Dioxide Spheres as Anode Material for Lithium Ion Battery with Largely Improved Rate Stability and Cycle Performance by Suppressing the Formation of Solid Electrolyte Interface Layer”, Journal of Materials Chemistry A. 3, 13340 (2015).

2. R. Wang, S. Wu*, Y. Lv, and Z. Lin*, "Partially crystalline Zn2GeO4 nanorod/graphene composites as anode materials for high performance lithium ion batteries”, Langmuir, 30, 8215 (2014).

1. S. Wu*, R. Wang, Z. Wang, and Z. Lin*, "CuGeO3 nanowires covered with graphene as anode materials of lithium ion batteries with enhanced reversible capacity and cyclic performance”, Nanoscale , 6, 8350 (2014).



4. Materials for H2 Generation and Photocatalysis



As the world energy crisis and pollution problems increase, it is imperative to take great advantage of clean energy. Solar energy has been considered as one of the most promising clean energies and has garnered much attention. There has been a considerably increased interest in using sunlight for hydrogen production and photo-degradation of environmental pollutants and toxics. In this project, we design various photocatalysts, such as core-shell nanoparticles, Janus nanoparticles, heterojunction electrodes and etc., which can efficiently utilize solar light (from UV light, visible light, infrared light to near-infrared light) to generate hydrogen and degrade organic pollutants.


Selected Publications:

4. M. Wang, D. Zheng, M, Ye, X. Xu, C. Lin, L. Sun, and Z. Lin*, "One-dimensional densely aligned perovskite-decorated semiconductor heterojunctions with enhanced photocatalytic activity”, Small. 11, 1436 (2015).

3. M. Wang, J. Ioccozia, L. Sun, C. Lin, and Z. Lin*, "Inorganic-modified semiconductor TiO2 nanotube arrays for photocatalysis”, Energy & Environmental Science , 7, 2182 (2014).(Invited Review Article)

2. M. Wang, L. Sun, Z. Lin*, J. Cai, K. Xie, and C. Lin, "p-n heterojunction photoelectrodes composed of Cu2O-loaded TiO2 nanotube arrays with enhanced photoelectrochemical and photoelectrocatalytic activities”, Energy & Environmental Science, 6, 1211 (2013).

1. M. Ye, J. Gong, Y. Lai, C. Lin, and Z. Lin*,High efficiency photoelectrocatalytic hydrogen generation enabled by palladium quantum dots sensitized TiO2 nanotube arrays”, Journal of the American Chemical Society, 134, 15720 (2012).



5. Materials for Thermoelectrics



Thermoelectric materials have garnered considerable attention due to their unique ability to directly convert heat to electricity and vice versa. Polymers carry many intrinsic advantages such as low thermal conductivity, solution processability, and roll-to-roll production for fabricating high-performance, lightweight, and flexible thermoelectric modules. In this project, we have been working on the preparation, modification and optimization of polymer-based thermoelectric materials, focusing especially on the facile strategies to minimize the thermal conductivity and maximize the power factor.


Selected Publications:

2. H. Xu, X. Pang, Y. He, M. He, J. Jung, H. Xia, and Z. Lin*, "An Unconventional Route to Monodisperse and Intimate Semiconducting Organic-Inorganic Nanocomposites”, Angewandte Chemie International Edition. 54, 4636 (2015).

1. M. He, F. Qiu, and Z. Lin*, "Towards high-performance polymer-based thermoelectric materials”, Energy & Environmental Science, 6, 1352 (2013).



6. Learning from “Coffee Ring”: Ordered Structures Composed of Polymers and Nanocrystals Crafted by Evaporative Self-Assembly


Controlled Evaporative Self-Assembly (CESA)



Drying of solutions has been the subject of increasingly active research aimed at better understanding the physics of evaporation process and capitalizing on its extreme simplicity to assemble a wide diversity of nonvolatile solutes into a multitude of complex ordered structures on the submicron length scale and beyond. In this project, we learn from very familiar “Coffee Ring” phenomena and develop simple yet robust preparation approaches that provide the capability of crafting structures with unprecedented regularity composed of polymers, nanoparticles, biomaterials, among others enabled by controlled evaporation-driven, flow-aided self-assembly in confined geometries. A broad range of important variables that can be brought into play to control deposition are investigated.


Selected Publications:

13. W. Han, M. He, M. Byun, B. Li, and Z. Lin*, “Large-scale hierarchically structured conjugated polymer assemblies with enhanced electrical conductivity”, Angewandte Chemie International Edition, 52, 2564 (2013). (Selected as Very Important Paper (VIP)).

12. M. Byun, W. Han, B. Li, X. Xin, and Z. Lin*, "An unconventional route to hierarchically ordered block copolymer on gradient patterned surface enabled by controlled evaporative self-assembly”, Angewandte Chemie International Edition, 52, 1122(2013).(Featured on the Frontispiece of Angewandte Chemie International Edition).

11. W. Han, M. Byun, B. Li, X. Pang, and Z. Lin*, "A simple route to hierarchically assembled micelles and inorganic nanoparticles”, Angewandte Chemie International Edition, 51, 12588 (2012).

10. W. Han and Z. Lin*, “Learning from “coffee ring”: ordered structures enabled by controlled evaporative self-assembly”, Angewandte Chemie International Edition, 51,1534 (2012) (Invited Review) (Featured on Frontispiece of Angewandte Chemie International Edition).

9. M. Byun, W. Han, B. Li, S. Hong, J. Cho, Q. Zou, and Z. Lin*, "Guided organization of λ-DNA into microring arrays from liquid capillary bridge”, Small,12, 1641 (2011). (Featured by Materials Views).

8. M. Byun, N. B. Bowden, and Z. Lin*, "Hierarchically organized structures engineered from controlled evaporative self-assembly",Nano Lett., 10,3111 (2010).

7. S. W. Hong, J. Wang, and Z. Lin*, "Evolution of ordered block copolymer serpentines into a macroscopic, hierarchically ordered web", Angewandte Chemie International Edition, 48, 8356 (2009).

6. S. W. Hong, M. Byun, and Z. Lin*, "Robust self-assembly of highly ordered complex structures by controlled evaporation of confined microfluids", Angewandte Chemie International Edition, 48, 512 (2009). (Selected as Very Important Paper (VIP); featured on Inside Front Cover of Angewandte Chemie International Edition (Jan 5, 2009 issue)).

5. S.W. Hong, W. Jeong, H. Ko, M. Kessler, V.V. Tsukruk, and Z. Lin*, "Directed self-assembly of gradient concentric carbon nanotube rings", Advanced Functional Materials,18, 2114 (2008). (Featured on Inside Front Cover of Advanced Functional Materials(issue 14)).

4. J. Xu, J. Xia and Z. Lin*, "Evaporation-induced self-assembly of nanoparticles from a sphere-on-flat geometry", Angewandte Chemie International Edition, 46, 1860 (2007).

3. S. W. Hong, J. Xia, and Z. Lin*, "Spontaneous formation of mesoscale polymer patterns in an evaporating bound solution", Advanced Materials, 19, 1413 (2007).

2. S. W. Hong, J. Xu, and Z. Lin*, "Template assisted formation of gradient concentric gold rings", Nano Letters, 6, 2949, (2006).

1. J. Xu, J. Xia, S. W. Hong, Z. Lin*, F. Qiu and Y. Yang, "Self-assembly of gradient concentric rings via solvent evaporation from a capillary bridge", Physical Review Letters, 96, 066104 (2006).


Flow-Enabled Self-Assembly (FESA)



The goal of this project is to develop a simple yet robust flow-enabled self-assembly (FESA) method to reproducibly create highly ordered structures over large areas composed of functional nanocrystals and diblock copolymers in a precisely controllable manner that dispenses with the need for lithographic techniques. Three specific research objectives will be pursued: (1). Synthesize luminescent nanocrystals with precisely controllable size, shape, and surface characteristics. (2). Craft hierarchically ordered structures composed of nanocrystals over large areas via the synergy between flow-enabled self-assembly (FESA) at the microscopic scale and spontaneous self-assembly at the nanoscale. (3). Reveal the mechanism of structure formation via theoretical modeling. The ability to predict the length scales of periodicity and compare them with experimental observations will provide useful insight into ordered structure formation. We will also wisely design and tailor the periodicity, height, and width of highly ordered structures by precisely controlling the movement of the lower substrate in the FESA process.


Selected Publications:

3. B. Li, C. Zhang, B. Jiang, W. Han, and Z. Lin*, "Flow-Enabled Self-Assembly of Large-Scale Aligned Nanowires”, Angewandte Chemie International Edition. 54, 4250 (2015). (Selected as Very Important Paper (VIP)).

2. B. Li, W. Han, B. Jiang, and Z. Lin*, "Crafting threads of diblock copolymer micelles via flow-enabled self-assembly”, ACS Nano, 8, 2936 (2014).

1. B. Li, W. Han, M. Byun, L. Zhu, Q. Zou, and Z. Lin*, "Macroscopic highly aligned DNA nanowires created by controlled evaporative self-assembly”, ACS Nano , 7, 4326 (2013).


Probing Mechanical Properties in Gradient Polymer Patterns Enabled by Surface Instabilities


Description coming soon



7. Functional Nanocomposites


All-Ferroelectric Organic-Inorganic Nanocomposites



Description coming soon


Selected Publications:

1. B. Jiang, X. Pang, B. Li, and Z. Lin*, "Organic-inorganic nanocomposites via placing monodisperse ferroelectric nanocrystals in direct and permanent connect with ferroelectric polymers”, Journal of the American Chemical Society. 137, 11760 (2015).


Multiferroic Nanocomposites



The use of block copolymers (BCPs) rather than a traditional homopolymer as the matrix offers unprecedented opportunities for controlling the spatial and orientational organization of nanoparticles in the nanocomposites by constraining the nanoparticles within desired block of copolymer. The magnetoelectric multiferroics are multifunctional materials that exhibit both magnetic order and electrical polarization in the same compound (i.e., ferromagnetic and ferroelectric). In these materials, the electric polarization can be induced by a magnetic field and conversely, and the magnetization can be induced by an electric field for use in spintronic devices, remote switchable devices, capacitors, sensors, magnetic data storage, etc. In this project, we intend to create novel nanocomposites, with long-range hierarchical order based on BCPs with nanoscopic multiferroic particles selectively incorporated into the target BCP domains may promise new opportunities for developing miniaturized multifunctional electromagnetic materials and devices with controlled dielectric permittivity and magnetic permeability.



8. Synthesis, Characterization and Self-Assembly of Nonlinear Functional Homopolymers and Block Copolymers via a Combination of Living Polymerizations (e.g., ATRP and RAFT) and Click Reaction


Star-like polymers have attracted considerable attention over the past decade due to their unique solution and solid-state properties. The main feature of star-shaped polymers, differing from the linear analogues of identical molar mass, is their compact structure (i.e., smaller hydrodynamic volume and radius of gyration) and high concentration of functional terminal groups, which enable them with higher solubility in common solvents, lower solution and melt viscosities, and modified thermal properties. Copolymer brushes composed of a flexible linear backbone and densely grafted side chains are a unique class of graft copolymers. Steric repulsion between polymeric side chains forces the backbone of copolymer brushes to adopt an extended chain conformation. In this project, we synthesize a large variety of non-linear polymers, including star-like homopolymers and block copolymers, bottle-brush copolymers, and macrocyclic brush copolymers, with well-defined molecular architectures, molecular weight, and ratio of two dissimilar blocks by sequential living polymerization (e.g., ATRPs) or by a combination of living polymerization with click reaction.


Selected Publications:

4. C. Feng, X. Pang, Y. He, Y. Chen, G. Zhang, and Z. Lin*, "A Versatile Strategy for Uniform Hybrid Nanoparticles and Nanocapsules”, Polymer Chemistry. 6, 5190 (2015). (featured on the Cover of Polymer Chemistry).

3. X. Pang, L. Zhao, C. Feng, R. Wu, and Z. Lin*, "Functional copolymer brushes composed of hydrophobic backbone and densely grafted conjugated side chains via a combination of click chemistry with living polymerization” Polymer Chemistry, 4, 2025 (2013)

2. Z. Lin*,“Novel amphiphilic multi-arm, star-like coil-rod diblock copolymers via a combination of click chemistry with living polymerization”, Macromolecules, 44, 7176 (2011).

1. X. Pang, L. Zhao, M. Akinc, J. K. Kim, and Z. Lin*, "Novel amphiphilic multi-arm, star-like block copolymers as unimolecular micelles”, Macromolecules, 44, 3746 (2011).


Nanocapsules



Unimolecular core-shell and hollow polymer nanoparticles with well-defined dimensions were crafted using spherical core-shell star-like diblock copolymers as templates. Monodisperse and structurally stable star-like diblock copolymers composed of inner degradable core blocks and outer photo-crosslinkable shell blocks were synthesized via a combination of two living polymerizations, namely, coordination-insertion ring opening polymerization (ROP) followed by reversible addition-fragmentation chain-transfer polymerization (RAFT). Subsequently, uniform unimolecular core-shell nanoparticles were successfully produced by photo-crosslinking the shell blocks of star-like diblock copolymers. The core diameter and shell thickness of nanoparticles are determined by molecular weights of inner core block and outer shell block, respectively, thereby rendering nanoparticles with tunable structural characteristics. The crosslinking density of nanoparticles can be readily controlled by varying the exposure time of star-like diblock copolymer templates to UV illumination. The selective degradation of inner core blocks yielded hollow polymer nanoparticles which retained structural integrity. The dye encapsulation and release studies revealed that unimolecular core-shell nanoparticles may be exploited as a new class of nanocarriers and promising drug nano-vehicles


Selected Publications:

1. C. Feng, X. Pang, Y. He, and Z. Lin*, "A Robust Route to Unimolecular Core-shell and Hollow Polymer Nanoparticles” Chemistry of Materials. 26, 6058 (2014).


Hyperbranched Polymers for Organic and Inorganic Nanoparticles



The development of reliable, generalizable and scalable nanoparticle synthesis techniques is an active area of research spanning several areas of engineering and science. Within this large group, various template-based techniques in which a nanoscopic scaffold is used to control the size, shape and composition are being investigated. This project focuses on one such technique relying on the ring opening multi-branching polymerization (ROMBP) of glycidol to produce hyperbranched polyglycerols (HPGs). Essential the star-like equivalent of linear poly( ethylene oxide) (PEO), HPG features a large number of exposed hydroxyl groups, is water soluble, biocompatible, and synthesizable in large quantities compared to other techniques. It is also useful as a polymerization initiator whose surface functionality can be controlled. This project focuses on synthesizing various star-like HPG copolymers to serve as templates for inorganic nanoparticles as well as organic nanoparticles outright.


Selected Publications:

1. J. Iocozzia, H. Xu, X. Pang, H. Xia, T. Bunning, T. White, and Z. Lin*, "Star-like polymer click-functionalized with small capping molecules: an initial investigation into properties and improving solubility in liquid crystals” RSC Advances. 4, 50212 (2014).


Macrocyclic Rings


Cyclic brush copolymers are of significant scientific interest due to its complex polymer architecture and unique properties. Synthesis of cyclic brush copolymers is challenging. Few studies on cyclic brush copolymers composed of PS/PEG as side chains were reported in the literature. However, cyclic brush copolymers grafted with conjugated polymers as side chains have never been investigated. In this project, a cyclic brush-like copolymer, poly(ethylene oxide)-g-poly(3-hexyl thiophene) (PEO-g-P3HT), composed of conjugated polymer P3HT as side chains was prepared by a combination of living anionic ring opening polymerization, quasi-living Grignard metathesis (GRIM) method and click chemistry. Due to its unique structure, its photovoltaic properties in solar cells is interesting and is currently being investigated.



9. Functional Nanomaterials


Earch Abundent Environmentally Friendly Copper Zinc Tin Sulfide (Cu2ZnSnS4) Nanocrystals



Achieving solar-to-electric energy conversion using inexpensive, abundantand nontoxic materials is an important goal. Solar cells based on thin films of semiconductors are emerging as inexpensive alternatives to silicon. However the two materials that yield the highest efficiency thin film solar cells, CdTe and Cu(In1-x,Gax)S2 (CIGS), have toxic element (i.e., Cd) and rare elements (i.e., indium (In) and gallium (Ga)). In this project, we intend to develop low-cost, environmentally friendly and high-efficiency Copper Zinc Tin Sulfide (Cu2ZnSnS4; CZTS) nanocrystal-based solar cells. CZTS is a potential material that has promising attributes for highly efficient, inexpensive solar cells made from abundant and nontoxic elements.


Selected Publications:

2. X. Xin, M. He, W. Han, and Z. Lin*, "Low-cost CZTS counter electrodes for high-efficiency dye sensitized solar cells”, Angew. Chem. Int. Ed., 50, 11739 (2011). (Selected as Very Important Paper (VIP); highlighted by Nanowerk; featured on the Front Cover of Angew. Chem. Int. Ed.).

1. J. Wang, X. Xin, and Z. Lin*, "Cu2ZnSnS4 nanocrystals and graphene quantum dots for photovoltaics”, Nanoscale, 3, 3040 (2011). (Invited Feature Article).


Upconversion Nanomaterials



Upconversion nanocrystals (UCNCs) represent a new class of nonlinear optical materials that can convert low energy radiation into higher energy radiation. Upconversion holds the promise of increasing the power conversion efficiency of solar cells by limiting sub-band gap losses, especially for large band gap solar cells. In this project, we synthesize UCNCs and utilize them to potentially yield high efficiency hybrid solar cells by the incorporating of UCNCs that expand the absorption spectrum to near infrared range.


Selected Publications:

1. D. Vennerberg and Z. Lin*, "Upconversion nanocrystals: synthesis, properties, assembly and applications”, Sci. Adv. Mater., 3, 26 (2011). (Invited Review).

2. W. Liao, D. Zheng, J. Tian, and Z. Lin*, "Dual-functional semiconductor-decorated upconversion hollow spheres for high efficiency dye-sensitized solar cells”, Journal of Materials Chemistry A. 3, 23360 (2015).


Plasmonic Nanostructures


Selected Publications:

1. B. Li, B. Jiang, H. Tang, and Z. Lin*, "Unconventional Seed-Mediated Growth of Ultrathin Au Nanowires in Aqueous Solution”, Chemical Science. 6, 6349 (2015).


Plasmonic/Magnetic Nanocrystals


Selected Publications:

1. D. Yang, X. Pang, Y. He, Y. Wang, G. Chen, W. Wang, and Z. Lin*, "Precisely Size-Tunable Magnetic/Plasmonic Core/Shell Nanoparticles with Controlled Optical Properties”, Angewandte Chemie International Edition . 127, 12259 (2015).


Ferroelectric/Magnetic Nanocrystals


Description coming soon



The Lin Research Group, last modified 08/08/2011 08:08 AM   Hit Count
School of Materials Science and Engineering @ Georgia Institute of Technology, Atlanta, GA, 30332

Copyright of Zhiqun Lin