Upconversion is becoming a more commonly used method to improve light absorption in photovoltaic/photocatalytic systems as well as for background-free bioimaging. The concept of upconversion involves converting lower energy photons to higher energies using paired absorber and emitter materials. This is particularly valuable when the efficiency of photovoltaics or the utilization of light within biological samples can be improved by upconverting two lower energy photons into one higher energy photo. Improving the efficiency of this process has led to numerous unique methods including plasmonic enhancement of the emitter via nano-structured gold or silver. Diane We's review takes a very multidisciplinary area of materials research and comprehensively surveys the methods of improving upconversion efficiency and the current state of the art. Contributing the results of her extensive survey to Citrination benefits all those working in the field as well as those selecting optimal materials for device and imaging applications.