Key Factors to Address the Issue of Global Energy and Environment Crisis

Zhiqiang Liu is currently based Institute of Semiconductors, Chinese Academy of Sciences (IOS, CAS). His research expertise is in building interdisciplinary teams to use compound semiconductor materials and devices for applications in the areas of nitride materials and Light Emitting devices. Zhiqiang Liu Energy and environment are critical important for our sustainable development. Novel materials and nanomanufacturing techniques provide new opportunities for this important research area. This issue has nine interesting papers dedicated to thermoelectrics, alkali-activated materials (AAMs), nano-materials, and perovskite quantum dots. With growing concerns for greenhouse gas emissions, AAMs have received enormous attention due to the benefit of low carbon footprint. Wengui Li et al. (DOI: 10.30919/esmm5f204) presents a critical review on the durability performance of alkali-activated system. It will provide guidelines for the research community as well as to the stakeholders of AAMs industries who seek sustainability in their products. Nitride materials have been widely used in lightemitting devices for decades. However, highly p-doping is still a big challenge, with hinds the further development of nitride-based devices. Liu et al. (DOI: 10.30919/esmm5f209) clarified the underlying physics and the acceptor ionization process in the In-Mg co-doping GaN, which is widely applicable for other co-doping nitride systems. The results will advance the current understanding of p-doping challenge and help to further address the issue of p-doping in wide-bandgap materials, especially from the viewpoint of band-structure engineering. Thermoelectrics is one of the most promising solutions to address the global energy crisis. Shuang Tang (DOI: 10.30919/esmm5f213) developed an efficient thermoelectric indicator based on band structure information to search for the most promising candidates from various band structure databases. This work provides new physical insights for searching and improving thermoelectric materials, and will stimulate more novel work in this field following the advancement in firstprinciples calculations to predict materials properties. It will provide important guidance for researchers to select and better engineer new materials. In recent years, as significant efforts have been emphasized on the exploitation of novel polymers with enhanced functionality. Yue Chen et al. (DOI: 10.30919/esmm5f214) developed a self-healing supramolecular polymer composite (LP-GO), which was designed and prepared via incorporation of graphene oxide (GO) to hyperbranched polymer. The simplicity of synthesis and the availability from renewable resources will ensure broad applications of these composites. The recycling of photocatalysts is in great demand. The microsized magnetic Fe O powders were successfully encapsulated by 3 4