Our group has developed probes to study the properties of very small crystals of interesting materials.  Recent experiments include electro-optic measurements of organic semiconductors and charge-density-wave materials using infrared diode lasers, electromechanical measurements of charge-density-wave materials using RF techniques, and thermal conductivity measurements on organic materials being developed for detector and thermoelectric applications.  For the latter, we use a few different dynamic (i.e. "ac") techniques, including a new photothermal method developed in our lab.

Recent Graduates: Emily Bittle (Ph.D. 2013, now at NIST), Hao Zhang (Ph.D. 2015, now at Alliance Fiber Optics Division of Corning Glass), Joshua Schlueter (M.S. 2016, now at Boeing Aircraft), and Yulong Yao (Ph.D. 2017, also now at Alliance Fiber Optics Division of Corning Glass), Maryam Shahi (Ph.D. 2020, now a Post-Doc in Materials Science Dept., UK), Ashkan Abtahi (joint student with Prof. Ken Graham, Ph.D. 2020, now a Post-Doc in Chemistry dept., Purdue U.)

Here is the Condensed Matter Group webpage: http://www.pa.uky.edu/condmat/

          Brill Group Publications (2009-2019)

• “Characterization of the torsional piezoelectric-like response of tantalum trisulfide associated with charge-density-wave depinning”, J. Nichols, D. Dominko, L. Ladino, J. Zhou, and J.W. Brill, Phys. Rev. B 79, 241110(R), (2009); 80, 039903(E) (2009).
• “Electro-optic search for threshold divergence of the CDW diffusion constant in blue bronze”, L. Ladino and J.W. Brill, Physica B: Physics of Condensed Matter, 404, 422 (2009).
• “Dynamics of the hysteretic voltage-induced torsional strain in tantalum trisulfide”, J. Nichols, C. Sandamali Weearasooriya, and J.W. Brill, J. Physics: Condens. Matt. 2, 334224 (2010).
• “Electro-optic measurement of carrier mobility in an organic thin-film transistor”, E.G. Bittle, J.W. Brill, and J.E. Anthony, App. Phys. Lett. 97, 0133302 (2010).
• “Torque and temperature dependence of the hysteretic voltage-induced torsional strain in tantalum trisulfide”, H. Zhang, J. Nichols, and J.W. Brill, Phys. Rev. B 84, 125134 (2011).
• “Electromechanical response of sliding charge-density-waves: Voltage-induced torsional strain in tantalum trisulfide”, J.W. Brill, H. Zhang, and J. Nichols, Physica B: Physics of Condensed Matter 407, 1737 (2012).
• “Dynamics of Charge Flow in the Channel of a Thin-Film Field-Effect Transistor”, E.G. Bittle, J.W. Brill, and J.P. Straley, J. Appl. Phys. 112, 094507 (2012).
• "Dynamic Infrared Electro-Optic Response of Soluble Organic Semiconductors in Thin Film Transistors", E.G. Bittle, J.W. Brill, and J.P. Straley, MRS Online Proceedings Library, 1501, 06 (2013).
• “Tuning electronic structures via epitaxial strain in Sr₂IrO₄ thin films”, J. Nichols, J. Terzic, E.G. Bittle, O.B. Korneta, L.E. DeLong, J.W. Brill, G. Cao, and S.S.A. Seo, App. Phys. Lett. 102, 141908 (2013).
• "Interlayer thermal conductivity of rubrene measured by ac-calorimetry", H. Zhang and J.W. Brill, J. Appl. Phys. 114, 043508 (2013).
• "Anisotropic electronic properties of a-axis-oriented Sr₂IrO₄ epitaxial thin films", J. Nichols, O.B. Korneta, J. Terzic, L.E. DeLong, G. Cao, J.W. Brill, and S.S.A. Seo, Appl. Phys. Lett. 103, 131910 (2013).        
• “Epitaxial Ba2IrO4 thin-films grown on SrTiO3 substrates by pulsed laser deposition”, J. Nichols, O.B. Korneta, J. Terzic, G. Cao, J.W. Brill, and S.S.A. Seo, Appl. Phys. Lett. 104, 121913 (2014).
• "Thermal diffusivities of functionalized pentacenes", H. Zhang, Y. Yao, Marcia M. Payne, J.E. Anthony, and J.W. Brill, Appl. Phys. Lett. 105, 073302 (2014).
• "Compressive strain-induced metal-insulator transition in orthorhombic SrIrO3 thin films", J.H. Gruenewald, J. Nichols, J. Terzic, G. Cao, J.W. Brill, and S.S.A. Seo, J. Mat. Res. 29, 2491 (2014).
• "An Organic Mixed Ion-Electron Conductor for Power Electronics", Abdellah Malti, Jesper Edberg, Hjalmar Granberg, Zia Ullah Khan, Jens. W. Andreasen, Xianjie Liu,  Dan Zhao, Hao Zhang, Yulong Yao, Joseph W. Brill, Isak Engquist, Mats Fahlman, Lars Wagberg, Xavier Crispin, and Magnus Berggren, Advanced Science, 2015, 201500305 (2015). 
• "Frequency-dependent photothermal measurements of transverse thermal diffusivity of organic semiconductors", J.W. Brill, Maryam Shahi, Marcia M. Payne, Jesper Edberg, Y. Yao, Xavier Crispin, and J.E. Anthony, Jnl. Appl. Phys. 118, 235501 (2015).
• "Investigations of metastable Ca2IrO4 epitaxial thin-films: systematic comparison with Sr2IrO4 and Ba2IrO4", M. Souri, J.H. Gruenwald, J. Terzic, J.W. Brill, G. Cao, and S.S.A. Seo, Scientific Reports 6, 25967 (2016).
• "Thermal Resistances of Thin Films of Small Molecule Organic Semiconductors", Y. Yao, Maryam Shahi, Marcia M. Payne, J.E. Anthony, and J.W. Brill, J. Mat. Chem. C 4, 8817 (2016).
• "Engineering One-Dimensional Quantum Stripes from Superlattices of Two-Dimensional Layered Materials", J.H. Gruenwald, J. Kim, H.S. Kim, J.M. Johnson, J. Hwang, M. Souri, J. Terzic, S.H. Chang, A.H. Said, J.W. Brill, G. Cao, H.Y. Kee, and S.S.A. Seo, Advanced Materials 29, 1603798 (2017). 
• "Optical signatures of spin-orbit exciton in bandwidth-controlled Sr2IrO4 epitaxial films via high-concentration Ca and Ba doping", M. Souri, B.H. Kim. J.H. Gruenwald, J.G. Connell, J. Thompson, J. Nichols, J. Terzic, B.I. Min, G. Cao, J.W. Brill, and A. Seo, Phys. Rev. B 95, 235125 (2017).
• "Ionic Thermoelectric Paper", Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas sundstrom, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph Brill, Tom Lindstrom, Magnus Berggren, and Xavier Crispin, J. Materials Chem. A, 5, 16883 (2017).
• "A free-standing high-output power density thermoelectric device based on structure-ordered PEDOT:PSS", Zaifang Li, Hengdu Sun, Ching-Lien Hsiao, Yulong Yao, Yiquan Xiao, Maryam Shahi, Yingzhi Jin, Alex Cruce, Xianjie Liu, Yingzhi Jin, Youyu Jiang, Wei Meng, Fei Qin, Thomas Ederth, Simone Fabiano, Weimin M. Cheng, Xinhui Lu, Jens Birch, Joseph W. Brill, Yinhua Zhou, Xavier Crispin, and Fengling Zhang, Advanced Electronic Materials 4, 1700496 (2018). .
• "Electronic and optical properties of La-dopes Sr3Ir2O7 epitaxial thin films", M. Souri, J. Terzic, J.M. Johnson, J.H. Gruenewald, J. Thompson, J.W. Brill, J. Hwang, G. Cao, and A. Seo, Phys. Rev. Materials 2, 024803 (2018).
• “Frequency-dependent photothermal measurement of thermal diffusivity for opaque and non-opaque materials; Application to crystals of TIPS-pentacene”, Maryam Shahi and J.W. Brill, J. Appl. Phys. 124, 155104 (2018).
• "Polymer gels with tunable ionic Seebeck coefficient for ultra-sensitive printed Thermopiles”, Dan Zhao, Anna Martinelli, Andreas Willfahrt, Thomas Fischer, Diana          Bernin, Zia Ullah, Maryam Shahi, Joseph Brill, Magnus Jonsson, Simone Fabiano, Xavier Crispin, Nature Communications 10, 1093 (2019).
• “Conducting polymer bolometers for low cost IR detection systems”, Anna Håkansson, Maryam Shahi, Joseph W. Brill, Simone Fabiano, Xavier Crispin, Advanced Electronic Materials 5, 1800975 (2019).
• “Altering the Radiation Chemistry or Electron-Beam Lithography with a Reactive Gas: A Study of Teflon AF Patterning under Water Vapor”, Mansoor A. Sultan, Sarah K. Lami, Armin Ansary, Douglas Strachan, Joseph W. Brill, and J. Todd Hastings, Nanotechnology 30, 305301 (2019).
• "The effect of drawing on the electrical, thermoelectrical, and mechanical properties of wet-spun PEDOT:PSS fibers", Ruben Sarabia-Riquelme, Maryam Shahi, Joseph W. Brill, and Matthew C. Weisenberger, ACS Applied Polymer Materials 1, 2157 (2019).
• "Nanometer-thick Sr2IrO4 Freestanding Films for Flexible Electronics", Sujan Shrestha, Matthew Coile, Menglin Zhu, Maryam Souri, Jiwoong Kim, Joseph W. Brill, Jinwoo Hwang, Jong-Woo Kim, and Ambrose Seo, ACS Applied Nano Materials, 3, 6310 (2020).