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Inorganic perovskite absorbers are promising candidates for next-generation photovoltaics due to their good thermal and light stabilities. Halide-mixed CsPbIxBr3−x reach a compromise between its structural tolerance and absorption edge, yet the power conversion efficiencies (PCEs) of the asfabricated cells can be considerably limited by the nonideal quality of solution-processed films. Here we demonstrated a fumigation strategy on colloidal perovskite films using dual-O-donor ethyl acetate (EA). By in-situ monitoring this stage with grazing-incidence wide-angle X-ray scattering technology, we reveal that EA fumigation would impose ripening barrier on colloidal inorganic perovskites and hence slow down the nucleation rate, leading to an intermediate state for processing high-crystallinity and oriented perovskite films with improved photophysical properties. An optimized PCE of 16.6% was finally yielded upon wide-bandgap (1.9 eV) perovskite absorber.

Organic–inorganic hybrid perovskite materials have attracted enormous attention owing to their extraordinary progress in both power conversion efficiency and stability. However, nonradiative carrier recombination occurring in the perovskite films and interface hinders its commercial viability as the next-generation photovoltaics. Doping with metal cations has been demonstrated to be efficacious for controlling charge transport and reducing charge recombination for perovskite solar cells. Herein, we report the homogeneous doping of entire perovskite solar cells by alkali cations via a dopant diffusion strategy from the hole transport layer. It was found that Rb+ ions enhanced the conductivity and optimized the energy level alignment. The diffused Rb+ ions within the perovskite layer could further reach the bulk films with modulated electronic states. The power conversion efficiency of the perovskite solar cell based on 1.0% Rb+-doped NiOx boosts to 21.80% with a high fill factor of 0.824. Unencapsulated Rb+-doped NiOx photovoltaic devices maintained 93.3% of their initial efficiency after storage in air for 1200 h.

Cesium lead halide perovskites are promising alternatives as light-absorbing materials for achieving perovskite solar cells with excellent thermal stability, but their inferior power conversion efficiency (PCE) and ambient instability are impeding their application. In this work, we show that liquid water can assist the formation of CsPbI2Br perovskites under the synergetic adsorption of H2O and dimethylsulfoxide (DMSO), which enabled uniform, [100] oriented CsPbI2Br films with a grain size up to 4.4 μm. It was found that a suitable amount of H2O helps desorb the DMSO molecules, and thus favours the formation of a cubic perovskite phase from DMSO complexed intermediates. Perovskite solar cells based on our strategy delivered an optimized PCE of 16.47% with a high open-voltage of 1.33 V, as well as good device stability against humidity, light and heat.

Cesium-based all-inorganic perovskite absorbers have attracted increasing attention due to their superior thermal stability, compared to their organic–inorganic counterparts. Up to now, it is a challenge to fabricate high-efficiency all-inorganic perovskite solar cells (PSCs) with low defect densities. Herein, we used bivalent metal chloride salts (SrCl2 and NiCl2) to optimize CsPbI2Br films. The experimental results indicate that this method could deliver high-quality films with improved electronic property. As a result, the champion device based on the 0.01 M SrCl2–doped CsPbI2Br film achieved a power conversion efficiency (PCE) of 16.07% with a high open voltage (VOC) of 1,322 mV, which is about 18% higher than that of the pristine device.

Pressurizer surge line is one of the key equipments of nuclear power plants. The thermal stratification due to the intersection of hot and cold fluids inside the pressurizer surge line may affect the safe operation of nuclear power plant. In order to investigate the stress distribution and fatigue characteristics of surge line subjected to long-term thermal stratified loadings, a mechanical model of the surge line was established. And then, according to different temperature distribution assumptions, thermal stress analysis and fatigue assessment were conducted. The results show that the maximum stress appears under the load condition with maximum temperature difference, and finer temperature distribution can obtain more accurate stress and displacement results. The maximum value of fatigue cumulative coefficient appears at the junction of straight pipe and elbow with large temperature difference.

The insertion of organic spacers into halide perovskite slabs has offered a trade-off between the efficiency and stability of perovskite solar cells (PSCs). The layered structure of diammonium-intercalated cesium lead halide perovskites is virtually unexplored, in contrast to several works on the monoammonium system. In this report, we find that perovskite with 1,4-butanediammonium (BDA) and cesium cations can only form n = 1 and n = 2 layered isologues defined by the chemical formula of (BDA)Csn-1Pbn(I0.7Br0.3)3n+1, while the n = 3-4 ones will self-construct into unique heterostructures comprising separated quantum wells (QWs; n = 1-2) and 3D (n = ∞) perovskites. We highlight that the 2D/3D heterostructures show a structural resemblance to that of bulk heterojunction in organics, thus improving the charge separation and transport more than surface passivation. Solar cells based on the (BDA)Cs3Pb4I9.1Br3.9 (n = 4) absorbing layer delivered a power conversion efficiency (PCE) reaching 9.49% with ideal light and thermal stability.

A highly transparent NiO layer was prepared by a solution processing method with nickel(II) 2-ethylhexanoate in non-polar solvent and utilized as HTM in perovskite solar cells. Excellent optical transmittance and the matched energy level lead to the enhanced power conversion efficiency (PCE, 18.15 %) than that of conventional sol-gel-processed NiO-based device (12.98 %).

A gradient heterosturcture is one of the basic methods to control the charge flow in perovskite solar cells (PSCs). However, a classical route for gradient heterosturctures is based on the diffusion technique, in which the guest ions gradually diffuse into the films from a concentrated source of dopants. The gradient heterosturcture is only accessible to the top side, and may be time consuming and costly. Here, the "intolerant" n-type heteroatoms (Sb3+ , In3+ ) with mismatched cation sizes and charge states can spontaneously enrich two sides of perovskite thin films. The dopants at specific sides can be extracted by a typical hole-transport layer. Theoretical calculations and experimental observations both indicate that the optimized charge management can be attributed to the tailored band structure and interfacial electronic hybridization, which promote charge separation and collection. The strategy enables the fabrication of PSCs with a spontaneous graded heterojunction showing high efficiency. A champion device based on Sb3+ doped film shows a stabilized power-conversion efficiency of 21.04% with a high fill factor of 0.84 and small hysteresis.