In conjunction with the energy crisis, environmental issues accompanying the utilization of energy resources have driven the development of new technologies that can realize highly efficient as well as environmentally friendly energy generation. The rise of green technology represents such an effort. In this respect, we are facing a new era of energy science: nanotechnology, a possible game changer. A recent endeavor to enhance the energy conversion efficiency of nanomaterial-based solar energy systems exemplifies the paradigm change.

Along with efficient harvesting, conversion and consumption of energy, the development of novel energy storage systems constitutes the main body of technical approaches to improve the overall efficiency of energy utilization. While the production of energy is mainly based on the large-scale plant industry, the energy produced is delivered to various consumer units ranging from residential houses to energy-intensive facilities. Since consumption of energy hardly occurs synchronously with its production, the development of energy storage systems is needed for stable use of the energy. Moreover, explosively growing demands for mobile electronics is also spurring development of energy storage systems that can accommodate high energy density in a compact device.