Imaging with electrogenerated chemiluminescence

The research contained herein discusses the application of electrogenerated chemiluminescence (ECL) to the construction of a scanning optical microscope. To our knowledge, we (along with a simultaneous publication by Allen J. Bard and co-workers) have been the first group to successfully implement and publish this type of new imaging device. Chapter 1 gives an introductory review of microelectrodes and ECL and the many analytical and physical applications of ECL. Chapter 2 describes the usage of ECL to examine the electroactive area of microelectrodes, and predicts, theoretically, the utility of microelectrodes supporting ECL as imaging devices. Chapter 3 discusses a unique phenomenon observed in our specific ECL experiments which allowed us to restrict the ECL supported at different geometry electrodes to regions of highest curvature. Chapter 4 is a culmination of the previous two chapters in which imaging using ECL at microelectrodes is demonstrated. A resolution of 560 nm is achieved. The output of the ECL is stable (collected intensity did not change more than 10% for a 2 hour experimental session) and has a well defined emission spectrum which could be applied to spectroscopic imaging experiments. Chapter 5 discusses the feasibility of constructing an electrochemically pumped dye laser, and some of the initial experiments which were conducted to that end. Chapter 6 describes a feedback mechanism for very precise control of the height of a scanning probe over sample surfaces. The technique relies on shear forces and utilizes a quartz crystal tuning fork which is dithered at its resonance frequency. The technique was applied to flame etched carbon fibers used in Chapter 4.