In recent years, research on organic‐inorganic lead halide two‐dimensional (2D) perovskites has been blossoming. 2D perovskites have completely different layered structures from three‐dimensional perovskites, with interleaved organic and inorganic layers, leading to 2D perovskite materials being more stable and possessing anisotropic electrical transport. Meanwhile, 2D organic‐inorganic lead halide perovskite single crystals are receiving increasing attention because of their remarkable properties, such as long charge carrier lifetime, low defect density, and high photoluminescence quantum yield, increasing their potential for optoelectronic applications. Previously, a series of material systems based 2D perovskites single crystals has been synthesized and applied in various device applications. In this review, the preparation methods of organic‐inorganic lead halide 2D perovskite single crystals, the growth principles, their photoelectric properties and several device applications are discussed.

This study reports the effect of water on the formation of a zinc oxide (ZnO) thin film and the performance of ZnO thin film transistors (TFTs).

No abstract

Incorporation of PSS into a PEI interfacial-layer improves the inverted-OPV, and it is further enhanced by using a robust TiOx–PEI:PSS combination.

Rationally managing the secondary‐phase excess lead iodide (PbI2) in hybrid perovskite is of significance for pursuing high performance perovskite solar cells (PSCs), while the challenge remains on its conversion to a homogeneous layer that is robust stable against environmental stimuli. We herein demonstrate an effective strategy of surface reconstruction that converts the excess PbI2 into a gradient lead sulfate‐silica bi‐layer, which substantially stabilizes the perovskite film and reduces interfacial charge transfer barrier in the PSCs device. The perovskite films with such bi‐layer could bear harsh conditions such as soaking in water, light illumination at 70 % relative humidity, and the damp‐thermal (85 °C and 30 % humidity) environment. The resulted PSCs deliver a champion efficiency up to 24.09 %, as well as remarkable environmental stability, e.g., retaining 78 % of their initial efficiency after 5500 h of shelf storage, and 82 % after 1000 h of operational stability testing.

The effects of post-treatments (150 C-thermal, humidity, and vacuum) on the cathode buffer layer of aqueous-solution-processed zinc oxide (ZnO) films on the performance of the inverted organic solar cells (OSCs) are investigated, based on poly(3-hexylthiophene)/[6,6]-phenyl-C 61 -butyric acid methyl ester (P3HT/PC 61 BM) as the active layers. The devices with the ZnO buffer layers that underwent thermal and vacuum post-treatments exhibited 17% and 15% increments in the power conversion efficiency (PCE) as compared to that of the cell without post-treatment on the ZnO layer, mainly due to the increases of the short circuit current (J sc ). It was found that the thermal and vacuum post-treatments reduced the defects and increased the electron mobility in the ZnO buffer layers, improving the electron extractions in the inverted OSCs. Both the 150 C-thermal and vacuum post-treatments are compatible with plastic substrates, showing a potential way to further improve the film properties of the lowtemperature processed ZnO buffer layers.

In this work, efficient mixed organic cation and mixed halide (MA0.7FA0.3Pb(I0.9Br0.1)3) perovskite solar cells are demonstrated by optimizing annealing conditions. AFM, XRD and PL measurements show that there is a better perovskite film quality for the annealing condition at 100 °C for 30 min. The corresponding device exhibits an optimized PCE of 16.76% with VOC of 1.02 V, JSC of 21.55 mA/cm2 and FF of 76.27%. More importantly, the mixed lead halide perovskite MA0.7FA0.3Pb(I0.9Br0.1)3 can significantly increase the thermal stability of perovskite film. After being heated at 80 °C for 24 h, the PCE of the MA0.7FA0.3Pb(I0.9Br0.1)3 device still remains at 70.00% of its initial value, which is much better than the control MAPbI3 device, where only 46.50% of its initial value could be preserved. We also successfully fabricated high-performance flexible mixed lead halide perovskite solar cells based on PEN substrates.

N–S-GAs 900 exhibit an interconnected porous 3D network with random orientation, crumpled sheets in SEM. The onset potential and limiting current density of N–S-GAs 900 are more positive and larger than other catalysts.