University of California, Riverside

Department of Chemistry



Faculty


 

 

Christopher Bardeen
Professor of Chemistry & Graduate Student Recruiter

 

Yale University - B.S. in Chemistry (1989)
University of California, Berkeley - Ph.D. in Chemistry (1995)
University of California, San Diego - Postdoc. Fellow (1995-1998)

Office: 134 Chemical Sciences
Phone O/L: (951) 827-2723/3079
Email: christopher.bardeen@ucr.edu
Research Area: Physical Chemistry, Analytical Chemistry, Environmental Chemistry, Materials Chemistry
Group Site

Biography


The goal of our research is to discover new and better ways to control and optimize photoinduced processes in organic and biological materials. Our research involves both the synthesis of new materials and the use of laser spectroscopy and microscopy to study dynamics. This work has practical applications ranging from solar energy conversion to photoprotection against skin cancer. We have three main areas of research.
  • EXCITON DYNAMICS IN ORGANIC SEMICONDUCTORS. One way to increase the efficiency of solar cells is to have one high energy photon produce two or more electron-hole pairs. We are interested in organic systems, like tetracene, that exhibit Exciton Fission, where a high energy singlet state splits into a pair of lower energy triplet excitons. In principle, this process can be harnessed to create two electron-hole pairs per absorbed photon. Once the excitons are created, they must diffuse to an interface where they can inject charge and generate photocurrent. One way to improve exciton transport is to use highly ordered, crystalline materials that can support delocalized electronic states and coherent transport. We are studying both the basic photophysics of organic molecular crystals to understand the origin and size of delocalized states. We are also studying how disorder affects the energy transfer dynamics in more disordered systems like dendrimers and amorphous polymers.
  • PHOTOACTUATED MOTION IN ORGANIC NANOSTRUCTURES. When a molecule absorbs light, it can undergo a photochemical reaction that requires molecular motion on the Angstrom scale, for example a cis-trans isomerization or a 4+4 cycloaddition. When many such reactions are lined up and occur together, the total displacement is the sum of all the smaller displacements and can be quite large. We are using molecular crystal nanorods to harness this effect in order to develop nanoscale photomechanical actuators, which could permit the remote control of very small objects in environments like the interior of a live cell.
  • SKIN PHOTOCHEMISTRY AND PHOTOBIOLOGY. The effects of solar UV radiation on the skin range from the cosmetic (photoaging) to dangerous (skin cancer). Understanding the chemical processes that occur in the skin is complicated by the fact that the skin is opaque, making traditional spectroscopic methods difficult to apply. We have developed two-photon fluorescence imaging protocols to monitor light-induced reactive oxygen species (ROS) at different depths within the skin. These fluorescence assays allow us, for example, to evaluate the ability of sunscreens to prevent ROS and photodamage in the skin. We are also studying the basic photophysics of sunscreen molecules both in solution and in formulations, which are basically highly concentrated emulsions.

Selected Publications

 

More Information 

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Department Information

Department of Chemistry
Chemical Sciences
501 Big Springs Road

Tel: (951) 827-3789 (Chair's Assistant)
Fax: (951) 827-2435 (confidential)
E-mail: eric.chronister@ucr.edu

Footer