Operational stability is crucial for the success in large-scale application of metal halide perovskites devices. The diffusion of volatile iodide component of perovskites can induce irreversible device degradation. Here, low-dimensional diffusion barriers were introduced to increase the operational stability of highefficiency large-area PSC modules. A negligible decay was observed after 1,000 h under severe test condition for a 15% high-efficiency solar module.

The electrical resistivity, heat capacity, superconducting upper critical magnetic field and magnetic susceptibility of NiBi 3 have been measured for the polycrystal and needle crystal. The temperature dependence of the resistivity ρ(T ) above the superconducting transition temperature can be explained by the parallel resistor formula. From ρ(T ), using the sum of two GruneisenBloch functions, we have obtained that the lower main value of the Debye temperature is 70 K and the higher one is 300 K. This is compatible with ω E ≡ 30.6 K and ω D ≡ 141 K obtained from the heat capacity using the hybrid Einstein-Debye model. We have compared the angular dependence of the critical magnetic field with that of the effective mass model and found an anisotropic mass ratio m b /m ⊥b ≈ 0.17 for the needle ( b-axis) crystal. Almost the same value of 0.14 is also obtained from the analysis of ρ(T ).

Corundum-structured iridium oxide (α-Ir2O3), showing p-type conductivity, is a strong candidate to form high-quality pn heterojunctions with α-Ga2O3. We fabricated α-Ir2O3/α-Ga2O3 pn heterojunction diodes and they showed well-defined rectifying current-voltage (I-V) characteristics with the turn-on voltage of about 2.0 V. The band alignment at the α-Ir2O3/α-Ga2O3 interface was investigated by X-ray photoemission spectroscopy, revealing a staggered-gap (type-II) with the valence- and conduction-band offsets of 3.34 eV and 1.04 eV, respectively. The total barrier height for electrons was about 2.4 eV, which reasonably agreed with the turn-on voltage in the I-V characteristics. This means that electrons are mainly attributed to electrical conduction around the turn-on voltage.