The Multiple Roles of Na Ions in Highly Efficient CZTSSe Solar Cells.

Sodium (Na) doping is a well-established technique employed in chalcopyrite and kesterite solar cells. While various improvements can be achieved in crystalline quality, electrical properties, or defect passivation of the absorber materials by incorporating Na, a comprehensive demonstration of the desired Na distribution in CZTSSe is still lacking. Herein, a straightforward Na doping approach by dissolving NaCl into the CZTS precursor solution is proposed.

Regulating the Interfacial Electronic Coupling of Fe N via Orbital Steering for Hydrogen Evolution Catalysis.

The capability of manipulating the interfacial electronic coupling is the key to achieving on-demand functionalities of catalysts. Herein, it is demonstrated that the electronic coupling of Fe N can be effectively regulated for hydrogen evolution reaction (HER) catalysis by vacancy-mediated orbital steering. Ex situ refined structural analysis reveals that the electronic and coordination states of Fe N can be well manipulated by nitrogen vacancies, which impressively exhibit strong correlation with the catalytic activities.

Electron density modulation of NiCoS nanowires by nitrogen incorporation for highly efficient hydrogen evolution catalysis.

Metal sulfides for hydrogen evolution catalysis typically suffer from unfavorable hydrogen desorption properties due to the strong interaction between the adsorbed H and the intensely electronegative sulfur. Here, we demonstrate a general strategy to improve the hydrogen evolution catalysis of metal sulfides by modulating the surface electron densities. The N modulated NiCoS nanowire arrays exhibit an overpotential of 41 mV at 10 mA cm and a Tafel slope of 37 mV dec, which are very close to the performance of the benchmark Pt/C in alkaline condition.