Bright electron beams and the technologies they drive are among the most powerful probes of matter at atomic length and time scales. Modern tools such as the X-ray free electron laser and ultrafast diffractometers and microscopes are driven by bright electron beams, but the performance of these machines can be curtailed by the achievable brightness of the system. This thesis investigates the photoemission performance of the alkali antimonide photocathodes for accelerators,focusing on the structural and stoichiometric properties, as well as optical interference effects that can be used to enhance the photoelectric yield at a desired excitation wavelength. Relatively unstudied alkali antimonide compounds Cs1Sb1 and Na-Sb are characterized in this work, including the development of a visible light photocathode in CsSb that exhibits resistance to oxidation.The epitaxial growth of the Cs3Sb cathode was explored on graphene and silicon carbide substrates using X-ray diffraction (XRD) and reflection high energy electron diffraction (RHEED) techniques, which lead to the growth of highlyordered Cs3Sb films. Measurements of enhanced quantum efficiency in alkali antimonides from an optical interference effect in the cathode-substrate multilayer was demonstrated, and a model for the interference effect is derived and applied to multiple species of alkali antimonides. Predictions from the model reveal that the QE can be enhanced by more than a factor of 5 at desired wavelengths by tuning the thickness of the cathode and substrate, while the thickness of the cathode itself can be obtained from the fits of the model to measurements. MOGA simulations were performed on a beamline driven by a cryogenic C-band photoinjector that is capable of implementing alkali antimonide photocathodes for the application of UED. We find this system can, in principle, achieve beam quality comparable to modern UED beamlines while exhibiting reduced dark current compared to modern radiofrequency guns. Finally, this thesis reports on the testing of alkali antimonides at high gradients in a series of experiments between the Cornell University Photocathode Laboratory and the UCLA PEGASUS laboratory. The growth and transfer of the cathode are described, the cathode characterization at high fields is presented, and the long term use of the cathodes for applications is discussed. Future directions for this work is also discussed.