In the 21st century, aggravating energy and environmental problems such as pollution, fossil fuel depletion, and global warming are ringing the alarm bell to human society. Therefore, clean and renewable energy materials as well as their devices are urgently demanded, which are the key and foundation to realize the transformation and utilization of new energy. The developments of energy storage and conversion techniques strongly depend on the achievements of material science.

Based on the modern instruments of making and analyzing novel materials for green energy and rapid accumulation of knowledge about them, researchers nowadays stand at a point that could be rich in huge opportunities to exterminate the energy and environmental problems. Indeed, we have seen a lot of progress in utilization of green energy, such as photovoltaic devices, bioenergy, and wind-driven power. Besides using green energy, the light-emitting devices also rock the lighting market by their capability of saving energy. However, the achievements are still far below the demands, and colleagues are making efforts in these fields.

This special issue selects 11 papers about energy materials, organic photovoltaic device, photodetector, thin-film solar cells, light-emitting device, and other energy saving and high energy efficiency related topics. This special issue enables interdisciplinary collaboration between science and engineering technologists in the academic and industrial fields. The objective is to provide an opportunity for interdisciplinary researchers to share their latest research achievements and let the potential readers learn some insightful concepts in energy related research. We hope this research progress can inspire more advanced ideas for the future development of energy technology.

Sheng-Po Chang
Jun Zhu
Shyh-Jer Huang
Hsin-Chieh Yu
Ting-Jen Hsueh
Hsin-Ying Lee