This books analyzes the fundamental science and properties of energy devices, including hybrid and organic solar cells, intercalation batteries, supercapacitors, and OLEDs. The authors cover concepts that apply to several types of devices, from a very basic level. This gives readers a general view of principles of operation of the nanoscale energy devices, since innovation in one kind of devices often finds applications in others. The book then moves into advanced coverage of the device modelling, which allows a realistic treatment of often complex devices based on nanostructured and polymer disordered materials.