We propose an intermediate-phase engineering strategy to achieve the robust interfacial contact by utilizing volatile organic salts. The introduction of organic cations (such as methylammonium and formamidinium) leads to the formation of an organic-inorganic hybrid perovskite intermediate phase in the initial film and promotes the high-quality interfacial contact of all-inorganic perovskite/metal oxide. A champion CsPb(I 0.75 Br 0.25 ) 3 -based device with a power conversion efficiency of 17.0% and an open-circuit voltage of 1.34 V was realized.

Herein, the application of Cu2O, SrCu2O2, and CuAlO2 as the hole‐transport materials (HTMs) in perovskite solar cells (PVSCs) using solar cell capacitance simulator (SCAPS‐1D) software, is numerically investigated. The effects of various parameters such as the perovskite layer thickness, the defect density of perovskite and interfaces, acceptor density of HTM and valance band offset of HTM/perovskite interface on device performance are studied. According to the simulation outcomes, the SrCu2O2 and CuAlO2 known as p‐type transparent conductive oxide are introduced as promising HTMs for fabrication of highly stable and efficient PVSCs. The Cu2O‐based devices exhibit the low power‐conversion efficiency (PCE) of 17.38% whereas, compared with 2,2′,7,7′‐tetrakis‐(N,N‐di‐4‐methoxyphenylamino)‐9,9′‐spirobifluorene (Spiro‐OMeTAD)‐based devices (PCE = 19.23%), the SrCu2O2 and CuAlO2 based‐devices show an enhanced PCE of 19.67% and 19.82%, respectively, under the hole‐transport layer (HTL) side illumination. This improvement can be attributed to lower light absorption in the HTL for devices based on SrCu2O2 and CuAlO2 than Cu2O due to wider bandgap which is formed.

Improving perovskite–HTM interface properties in solar cells is more important than just improving HTM hole mobility.

Titanium oxide (TiO2)-based photodetectors were fabricated using a thermal oxidation technique. The effect of two different annealing temperatures on morphology, structure, and I-V characteristics has been investigated. TiO2/Si heterostructure exhibited diode-like rectifying I-V behavior both in dark and under illumination. Dependence in photoresponse on annealing temperature was observed that was related to effective surface area of quasi-one-dimensional TiO2 nanostructures. Fabricated TiO2/Si diodes in 850 °C as the lower annealing temperature showed higher responsivity and sensitivity compared with grown ones in 950 °C (R850 °C/R950 °C ∼ 5 and S850 °C/S950 °C ∼ 1.6). Rather good photoresponse and simple fabrication process make the 850 °C-TiO2/Si diode a promising candidate for practical applications.