Stability Assessment of p-i-n Perovskite Photovoltaic Mini-Modules Utilizing Different Top Metal Electrodes.

Long-term stability is one of the major challenges for p-i-n type perovskite solar modules (PSMs). Here, we demonstrate the fabrication of fully laser-patterned series interconnected p-i-n perovskite mini-modules, in which either single Cu or Ag layers are compared with Cu/Au metal-bilayer top electrodes. According to the scanning electron microscopy measurements, we found that Cu or Ag top electrodes often exhibit flaking of the metal upon P3 (top contact removal) laser patterning.

Compositional and Interfacial Engineering Yield High-Performance and Stable p-i-n Perovskite Solar Cells and Mini-Modules.

Through the optimization of the perovskite precursor composition and interfaces to selective contacts, we achieved a p-i-n-type perovskite solar cell (PSC) with a 22.3% power conversion efficiency (PCE). This is a new performance record for a PSC with an absorber bandgap of 1.

Switching adhesion forces by crossing the metal-insulator transition in Magnéli-type vanadium oxide crystals.

Magnéli-type vanadium oxides form the homologous series V(n)O(2) (n) (-1) and exhibit a temperature-induced, reversible metal-insulator first order phase transition (MIT). We studied the change of the adhesion force across the transition temperature between the cleavage planes of various vanadium oxide Magnéli phases (n = 3 … 7) and spherical titanium atomic force microscope (AFM) tips by systematic force-distance measurements with a variable-temperature AFM under ultrahigh vacuum conditions (UHV). The results show, for all investigated samples, that crossing the transition temperatures leads to a distinct change of the adhesion force.

Ultrathin SiO(2) layers on Si(111): preparation, interface gap states and the influence of passivation.

An essential prerequisite for the successful application of Si/SiO(2) nanostructures in photovoltaics is the realization of well-defined and abrupt interfaces with low densities of interface gap states. Here, a complete in situ process from preparation and hydrogen passivation to interface gap state analysis by near-UV photoelectron spectroscopy without breaking ultrahigh vacuum (UHV) conditions is introduced. It is demonstrated that by RF plasma oxidation of Si(111) substrates with thermalized neutral oxygen atoms, ultrathin SiO(2) layers can be realized with compositionally and structurally abrupt Si/SiO(2) interfaces and a minimal amount of intermediate oxidation states bridging the transition from Si to SiO(2).

Cluster assembled nanostructures: designing interface properties.

Overlayer structures can be formed on surfaces by the deposition of preformed clusters from the gas phase containing from only a few up to a few hundred atoms. By this method, nanostructures with novel chemical and physical properties can be stabilized. This article presents the results obtained using the simple molecular cluster Sb4 as the precursor for deposition and nanoparticle assembly on various surfaces, and under various conditions.