About

Hongjie Dai's research lab at Stanford University

Research in Professor Hongjie Dai's group has been bridging and interfacing chemistry, physics, and materials and biomedical sciences to develop advanced nanomaterials with properties useful in electronics, energy storage, nanomedicine, and more. Recent developments include fluorescence imaging of biological systems in the second near-infrared window, ultra-sensitive diagnostic assays, a fast-charging, inexpensive aluminum battery and affordable, energy efficient electrocatalysts that splits water into oxygen and hydrogen fuel.

Hongjie Dai began his formal studies in physics at Tsinghua University in Beijing (B.S. 1989) and applied sciences at Columbia University (M.S. 1991). Following his doctoral work at Harvard University (Ph.D. 1994) and postdoctoral research at Rice University, he joined the Stanford faculty in 1997, and in 2007 was named J. G. Jackson and C. J. Wood Professor of Chemistry. Among various awards for his contributions to nanoscience, he has been recognized with the American Chemical Society's ACS Pure Chemistry Award, the Julius Springer Prize for Applied Physics, the American Physical Society's APS James C. McGroddy Prize for New Materials, and the Materials Research Society's MRS Mid-Career Researcher Award. He has been elected to the American Academy of Arts and Sciences, the AAAS and the National Academy of Sciences.

Research in the Dai Laboratory works on the synthesis and basic understanding of carbon based nanomaterials, plasmonic materials, strongly coupled carbon-inorganic hybrid materials, novel electrocatalysts and battery materials, with applications spanning nanoelectronics, nanobiotechnolgy, nanomedicine, energy storage and electrocatalysis.

Development of Novel Nanoscale Materials

The Dai Laboratory has advanced and popularized chemical vapor deposition for carbon nanotube growth, including vertically aligned nanotubes and the first patterned growth of single-walled carbon nanotubes on silicon wafers and other substrates, which facilitated studies of the intrinsic physical properties of carbon nanotubes worldwide. Dai's group also pioneered the synthesis of graphene nanoribbons by unzipping carbon nanotubes.

The Dai group has been developing the synthesis of various nanocrystals and nanoparticles on carbon nanotubes and graphene with controlled degrees of oxidation, producing a class of strongly coupled hybrid materials with covalent bonding between inorganic particles and nano-carbon with advanced properties for electrochemistry, electrocatalysis and photocatalysis.

The Dai group has been working on a novel nano-structured plasmonic gold film with high uniformity over large substrates for near-infrared fluorescence enhancement by up to 100-fold, opening multiplexed, ultra-sensitive biological assays of protein and antibody disease biomarkers using near-infrared fluorescence.

Nanoscale Physics and Devices

The Dai's group has been working on nanocarbon physics and electronics. The high quality nanotubes from the group's synthesis are widely used to investigate the intrinsic electrical, mechanical, optical, electro-mechanical and thermal properties of quasi-one dimensional systems. Dai's group demonstrated nanotube based electronic nanosensors, developed Pd ohmic contacts to nanotubes, investigated ballistic electron transport in nanotubes and demonstrated ballistic carbon nanotube field effect transistors with integrated high kappa dielectrics.

Nanomedicine

Dai's group pioneered biological research with carbon nanotubes and nano-graphene through developing π-π stacking non-covalent functionalization chemistry, molecular cellular delivery (drugs, proteins and siRNA), in vivo mouse model drug delivery with nanocarbon for cancer therapy, and in vivo photothermal ablation of cancer utilizing near-infrared light absorption. The nanocarbon materials used include broadly carbon nanotubes, nano-graphene and graphitic shell-magnetic core nanoparticles. Using nanotubes as novel contrast agents, Dai's group developed biological imaging in vitro and in vivo using Raman, photoacoustic and fluorescence modalities through various collaborations with medical group.

NIR-II fluorescence imaging

Dai's group has been pioneering NIR-II fluorescence imaging for deep-tissue biological imaging in vivo using simple one-photon techniques. Dai's laboratory exploited the physics of reduced light scattering in the newly coined NIR-II (1000-1700 nm) window and utilized the intrinsic fluorescence of nanotubes in this range to push the limit of tissue penetration depth for fluorescence imaging, exemplified by non-invasive through-skull brain imaging of stroke in mice, and imaging of mouse tumor models, hindlimb ischemia and traumatic brain injury. Video-rate (~ 30 frames per second) NIR-II imaging was developed to measure blood flows in single blood vessels in real time, resolving features related to cardiac cycles. Dai's group developed novel NIR-II fluorescence agents including carbon nanotubes, quantum dots, conjugated polymers and organic dyes that could potentially replace ICG for clinical translation. Zero-autofluorescence biological imaging is achieved with excitation at ~ 800nm and detection in the ~ 1500 nm range.

Electrocatalysis and Aluminum Ion Battery

The Dai group has been developing nanocarbon-inorganic particle hybrid materials as a new direction for the group, leading to substantial progress to energy research. His group developed novel electrocatalysts for oxygen reduction and water splitting catalysts including NiFe layered-double-hydroxide for oxygen evolution. Recently, Dai's group has been developing aluminum ion battery with graphite cathodes that represent a new dimension in battery science and technology.

Contact Info

Hongjie Dai

Department of Chemistry

Stanford University

William Keck Science Building rm 125

Stanford, CA 94305-5080

tel 650 723 4518

fax 650 725 9793

email hdai1@stanford.edu