Detection of Solvated Electrons from Photoexcited Diamond

Diamond possesses the unique ability to act as a facile and robust electron emitter in both vacuum and non-vacuum environments. While emission into vacuum has been widely studied, much less is known about diamond electron emission into water. Direct detection of electrons photoemitted into water is challenging because of the short lifetime (hundreds of nanoseconds), small cross-section, and near proximity of the electrons to the liquid interface. We have been developing improved methods for detecting solvated electrons at solid-liquid interfaces using transient absorption spectroscopy. Our experiments using a 705 nm detection wavelength (near the maximum of solvated electron absorption) gives rise to intensity changes on the order of ~ 10^-3 (0.1%), with lifetimes in agreement with expected values. In order to collect the complete solvated electron spectrum and enhance the specificity of detection, we have recently been developing a transient absorption system for complete spectroscopic analysis of solvated electrons produced via diamond photoemission. In this talk we will describe our efforts to detect solvated electrons from diamond into water, and efforts toward complete spectroscopic characterization of the transient absorption spectra. As time permits, we will also discuss the possibility of electron emission from other wide-bandgap materials.