Local structure of potassium doped nickel oxide: A combined experimental-theoretical study

Progress, highlights and perspectives on NiO in perovskite photovoltaics

“…Interestingly, a combined XAFS and theoretical investigation on molecular beam epitaxy (MBE) deposited K-doped NiO lms suggested that potassium tends to cluster and oat to the NiO surface. At the same time the formation in traces of K 0 Ni is promoted by additional adjacent oxygen and/or nickel vacancies in order to compensate for the large radius of K + , 97 as sketched in Fig. 2b.…”

Doped NiO: the Mottness of a charge transfer insulator

“…A value for the Hubbard U of U = 4.7 eV for PBE+U was used, based on a previous quantum Monte Carlo study for K-doped NiO 19 . We note that geometrical optimization using PBE+U and variational Monte Carlo simulations give essentially identical results 20 . For the PBE+U calculations, normconserving energy-consistent pseudopotentials proposed by Burkatzki, Filippi, and Dolg were used with 400 Ry plane-wave kinetic energy cut-off 21,22 .…”

“…We note that the lattice parameter increases much more rapidly with indium-than with potassium-doping. We attribute this different response to indium substitutionally doping NiO and thereby expanding the lattice -the ionic radius of In 3+ is about 30% larger than the ionic radius of Ni 2+ -whereas in addition to substitution, potassium/oxygen-vacancy clusters are formed upon potassium doping 20 . These defect clusters can absorb strain locally, which reduces the tendency to a global lattice expansion.…”

Stability and Efficiency Enhancement of Antimony Selenosulfide Solar Cells with Inorganic SnS‐Modified Nickel Oxide Hole Transport Materials

“…To solve this problem, many researchers have used metal ion doping to increase the conductivity and improve the energy band alignment of the device, such as K + , Mg 2+ , Cu 2+ . [25][26][27] But ion doping may introduce the defects to the NiO x crystal. In addition, scientists also conducted surface treatment or surface doping of NiO x films with organic small molecules, such as ethanolamine and hexa fluoro tetra cyanonaphtho quinodimethane (F6TCNNQ).…”