Advent of alkali metal doping: a roadmap for the evolution of perovskite solar cells.

Metal-halide hybrid perovskites have prompted the prosperity of the sustainable energy field and simultaneously demonstrated their great potential in meeting both the growing consumption of energy and the increasing social development requirements. Their inimitable features such as strong absorption ability, direct photogeneration of free carriers, long carrier diffusion lengths, ease of fabrication, and low production cost triggered the development of perovskite solar cells (PSCs) at an incredible rate, which soon reached power conversion efficiencies up to the commercialized level. During their evolution process, it has been witnessed that alkali metal cations play a pivotal role in the crystal structure as well as intrinsic properties of hybrid perovskites, thus enabling the unique positioning of the correlated doping strategy in the development history of PSCs in the past decade.

Single-Atom Vacancy Defect to Trigger High-Efficiency Hydrogen Evolution of MoS.

Defect engineering is widely applied in transition metal dichalcogenides (TMDs) to achieve electrical, optical, magnetic, and catalytic regulation. Vacancies, regarded as a type of extremely delicate defect, are acknowledged to be effective and flexible in general catalytic modulation. However, the influence of vacancy states in addition to concentration on catalysis still remains vague.