Evidence for laser action driven by electrochemiluminscence

Emission of light from excited-state dye molecules can be driven by the electron transfer between electrochemically generated anion and cation radicals-a process known as electrochemiluminescence(1-5) (ECL). ECL has been investigated for both display(6) and laser applications(7-9). The latter is of particular interest as, in contrast to conventional dye lasers, a laser operating by this principle would not require an additional laser source optically to pump the dye into the required excited state, and may offer additional advantages in terms of power, tunability and range of available wavelengths. But the pumping rate hitherto achieved by ECL is two orders of magnitude lower than the optical pumping threshold(9). Here we describe a device structure designed to enhance the efficiency of the ECL process, and present evidence that laser action has been realized in such a structure: the ECL spectrum is strongly modulated by the device structure, the output intensity shows a clear threshold as the drive current increases, and spectral narrowing is observed as the intensity increases.