Associate Professor, Mechanical Engineering
EducationPh.D., University of California, Berkeley
Nanostructured organic-inorganic hybrid materials aim to combine the manufacturability of plastics with the transport properties of semiconductors. Over the last twenty years, researchers focused on electronic applications (e.g. organic electronics), but the field is now expanding to address the challenges of energy demand and climate change. Nanostructured hybrids are promising replacements for bulk semiconductor photovoltaic and thermoelectric materials because they have controllable feature sizes at length scales characteristic of transport processes. The use of organic-inorganic nanostructured materials can also unlock new opportunities in mature energy fields, such as thermal energy storage and heat transfer enhancement.
My expertise in heat transfer, nanoscale transport, and organic-inorganic self-assembly is uniquely situated to develop nanostructured hybrid materials that push the limits of energy conversion, storage, and efficiency. Our projects leverage ultrafast laser techniques and micro/nano fabrication to explore new materials and reveal new thermal transport properties of existing materials.
Regner, K.T., D.P. Sellan, Z. Su, C.H. Amon, A.J.H. McGaughey, and J.A. Malen, Broadband phonon mean free path contributions to thermal conductivity measured using frequency domain thermoreflectance. Nature Communications, 4:1640 doi:10.1038/ncomms2630(2013).
W. L. Ong, S. M. Rupich, D. V. Talapin, A. J. H. McGaughey & J. A. Malen, Surface chemistry mediates thermal transport in three-dimensional nanocrystal arrays, Nature Materials, doi:10.1038/nmat3596 (2013).
Y. Yan, J. A. Malen, Periodic heating amplifies the efficiency of thermoelectric energy conversion. Energy & Environmental Science, doi: 10.1039/C3EE24158K(2013).
Schiffres, S. N., K. H. Kim, L. Hu, A. J. H. McGaughey, M. F. Islam, J. A. Malen, Gas diffusion, energy transport, and thermal accommodation in single-walled carbon nanotube aerogels. Advanced Functional Materials, 22, 5251–5258 doi:10.1002/adfm.201201285 (2012).
Su, Z., L. Huang, F. Liu, J. P. Freedman, L. M. Porter, R. F. Davis, J. A. Malen, Layer-by-layer thermal conductivities of the Group III nitride films in blue/green light emitting diodes. Applied Physics Letters, 2012. 201106 (100).
Yee, S.K.*, J.A. Malen*, A. Majumdar, and R.A. Segalman, Thermoelectricity in Fullerene-Metal Heterojunctions. Nano Letters, 2011.
Schiffres, S. and J.A. Malen, Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber. Review of Scientific Instruments, 2011. 064903 (82).
Malen, J.A., K. Baheti, T. Tong, Y. Zhao, J.A. Hudgings, and A. Majumdar, Optical Measurement of Thermal Conductivity Using Fiber Aligned Frequency Domain Thermoreflectance (FAFDTR). ASME Journal of Heat Transfer, 2011.
Malen, J.A., S.K. Yee, A. Majumdar, and R.A. Segalman, Fundamentals of energy transport, energy conversion, and thermal properties in organic-inorganic heterojunctions. Chemical Physics Letters, 2010. 491(4-6): p. 109-122.
Malen, J.A., P. Doak, K. Baheti, T.D. Tilley, A. Majumdar, and R.A. Segalman, The Nature of Transport Variations in Molecular Heterojunction Electronics. Nano Letters, 2009. 9(10): p. 3406-3412.
Malen, J.A., P. Doak, K. Baheti, T.D. Tilley, R.A. Segalman, and A. Majumdar, Identifying the Length Dependence of Orbital Alignment and Contact Coupling in Molecular Heterojunctions. Nano Letters, 2009. 9(3): p. 1164-1169.
Baheti, K.*, J.A. Malen*, P. Doak, P. Reddy, S.Y. Jang, T.D. Tilley, A. Majumdar, and R.A. Segalman, Probing the chemistry of molecular heterojunctions using thermoelectricity. Nano Letters, 2008. 8(2): p. 715-719.