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Halide perovskites are intensively studied for applications in optoelectronic devices because of their outstanding properties and relatively low cost. However, the common precursor solutions for perovskite fabrication are rather unstable in the presence of moisture and oxygen, limiting the large‐scale low‐cost production of perovskite. Herein, water is used counterintuitively to formulate an ambient stable perovskite precursor, which is peculiar in that it is solid at room temperature but becomes a liquid at 75 °C. The non‐fluidity of the precursor stemmed from the water‐assisted intermediate fiber assembly, conferring high damp air stability. Yet the heat‐liquefiability made the precursor highly processible for perovskite growth, and when guided by polyvinyl pyrrolidone coordination with Pb2+, the perovskite can preferentially grow along the [200] direction, significantly improving the film quality. To demonstrate the utility of the precursor, it has been used to fabricate self‐driven halide perovskite photodetectors, which exhibited a low noise current of 2.0 × 10−14 A Hz−1/2, a high specific detectivity up to 1.4 × 1013 Jones, and high stability of 20 days of operation with only < 5% external quantum efficiency decay. This type of solid‐liquid convertible precursor opens up new opportunities for wider applications of perovskites. [ABSTRACT FROM AUTHOR]

Summary: The stability and toxicity of perovskite solar cells are still preventing full industrialization. Therefore, lead‐free all‐inorganic double perovskite materials have become the focus of research in recent years. Our group proposed a new narrow bandgap lead‐free double perovskite solar cell using a high‐quality Cs2PtI6 film. In this paper, for the purpose of exploring the trend in the bandgap and stability of the perovskite‐derived Cs2PtI6 substituted by halogen ions, we performed a first‐principles investigation based on density functional theory to study the structural and electronic properties of Cs2PtI6−yCly, Cs2PtI6−yBry, Cs2PtBr6−yCly (y = 0, 1, 2, 3, 4, 5, 6). The calculated structural parameters revealed a good mechanical stability for all these compounds, and the trend in the formation energy indicated that the substitution of I− with Cl− and Br− can significantly reduce the energy and improve the thermodynamic stability. Through a comparative analysis of the electronic properties of Cs2PtX6 (X = Cl, Br, I), we found that the substitutional doping of halogen ions can effectively adjust the bandgap and show an obvious change trend. The present study may demonstrate an effective theoretical guidance for preparing lead‐free all‐inorganic perovskite solar cell materials with appropriate bandgap and excellent stability. [ABSTRACT FROM AUTHOR]

Herein, it is reported that the stability of a halogenated perovskite (PVK) solar cell consisting of an fluorine‐doped tin oxide (FTO) substrate/TiO2/CH3NH3PbI3/N2,N2,N2′,N2′,N7,N7,N7′,N7′‐octakis(4‐methoxyphenyl)‐9,9′‐spirobi[9H‐fluorene]‐2,2′,7,7′‐tetramine/Ag/Au structure is improved by adding Sb‐xanthate to the PVK layer without large loss of efficiency. The Sb‐element‐rich layer is observed on top of the PVK layer. From the X‐ray photoelectron spectroscopy (XPS) study, it is concluded that an inorganic SbxOy passivation layer on the PVK layer is prepared by baking the solution of the Sb‐xanthate and the PVK precursor. The inorganic layer prevents moisture and oxygen from penetrating into the PVK layer. This article provides a new method to obtain a passivation layer on a PVK layer by baking a mixture solution in one step for improving solar cell stability. [ABSTRACT FROM AUTHOR]

A high‐performing inverted perovskite solar cell (PSC) always relies on the hole transporting layer (HTL) quality and its interfaces. This work investigates the impact of La incorporation within the NiOx matrix for defects passivation, thus leading to high charge extraction ability and stability without compromising its power conversion efficiency. In the presence of La, the La–NiOx quality is clearly improved; without the formation of pinholes. In addition, the inclusion of La alters the energy band alignment; consequently, enhancing the hole transportation and widening the Voc (>1 V), as compared to the pristine NiOx. The beneficial effect of La was further revealed through the photoluminescence measurement and density of states (DOS) analysis, in which trap states are passivated by La. More importantly, the perovskite solar cell, with La–NiOx as the HTL, exhibits 21 % enhancement in efficiency and a remarkable stability that is greater than that of pristine NiOx. This also unlocks an opportunity for commercialization. Inversion therapy: A high‐performing inverted perovskite solar cell (PSC) always relies on the hole transporting layer (HTL) quality and its interfaces. This study concerns the impact of lanthanum incorporation within the NiOx matrix for high conductivity, charge extraction ability, and stability without compromising its power conversion efficiency. [ABSTRACT FROM AUTHOR]

Despite the remarkable performance of organometallic halide perovskite solar cells (PSCs), their ultimate stability is still a major issue that inhibits the commercialization of this eminent technology. Herein, melamine hydroiodide (MLAI) is added to function methyl ammonium (CH3NH3+, MA+) lead iodide perovskite for fabricating structured perovskite with enhanced photovoltaic performance and stability in the harsh ambient atmosphere (35 °C, 60–70% relative humidity). Nearly no new phase formed even incorporated 25 mol.% MLAI induces the strain in the perovskite crystal structure. The MLAI‐structured perovskite film shows a denser and smoother surface than the pristine MAPbI3 perovskite. Planar PSCs based on 2 mol.% MLAI‐functionalized perovskite show 17.2% power conversion efficiency with nearly no hysteresis which is much higher than pristine MAPbI3 PSCs. Most importantly, the solar cell devices based on 2 mol.% MLAI‐functionalized perovskite still retain over 90% of the initial performance after being kept in ambient atmosphere for more than 560 h without encapsulation. Melamine hydroiodide (MLAI) has been successfully introduced for preparing hetero structured MAPbI3 perovskite for enhancing the photovoltaic performance and stability of perovskite solar cells in a robust humid ambient atmosphere (35 °C, 60–70% relative humidity). The power conversation efficiency of perovskite solar cells based on MLAI functionalized perovskite is 25% higher than that of pristine MAPbI3 perovskite with nearly no hysteresis and high stability. [ABSTRACT FROM AUTHOR]

Despite the eminent performance of the organometallic halide perovskite solar cells (PSCs), the poor stability for humidity and ultraviolet irradiation is still major problem for the commercialization of PSCs. Herein, a novel functional organic compound 1‐(ammonium acetyl)pyrene is successfully introduced for preparing the 2D/3D heterostructured MAPbI3 perovskite. Because of the functional organic pyrene group with high humidity resistance and strong absorption in the ultraviolet region, the 2D/3D perovskite film shows notable stability with no degradation in ≈60% relative humidity after even six months and exhibits a high ultraviolet irradiation stability which keeps nearly no degradation after 1 h in the UV Ozone treatment. Planar PSCs are fabricated in the ≈60% relative humidity air outside glovebox. The champion efficiency of (PEY2PbI4)0.02MAPbI3 perovskite solar cells is 14.7% with nearly no hysteresis which is equal performance of 3D MAPbI3 devices (15.0%). This work presents a new direction for enhancing the solar cells' performance and stability by incorporating a functional organic aromatic compound into the perovskite layer. A novel organic compound 1‐(ammonium acetyl) pyrene is successfully introduced for preparing the 2D/3D heterostructured MAPbI3 perovskite. Because of the functional organic pyrene group with high humidity resistance and strong absorption in the ultraviolet region, the 2D/3D perovskite showed notable stability, comparable photovoltaic performance in humid air atmosphere and ultraviolet irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] The power conversion efficiency (PCE) of perovskite solar cells (PSCs) is already higher than those of other thin-film photovoltaic technologies, but the stability issue limits their applications. The introduction of sulfur-based compounds in PSCs could contribute to their stability. Herein, sulfur-based compounds have been embedded into each functional layer to stabilize carbon-based PSCs (C-PSCs). Results showed that the simultaneous introduction of sulfur-based compounds could decrease the trap states of perovskite film, enlarge the grain size of perovskite, and accelerate the charge transfer and extraction, leading to an improved performance. Comparing with the device without sulfide (10.77%), all sulfide C-PSCs obtained a PCE of 15.38%. The stability test showed much better resistance to humidity and thermal stress for all sulfide C-PSCs. They could retain 80% of initial PCE after aging about 700 h at relative humidity (RH) 45% ± 10% and 80 °C. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have attracted a lot of attention from researchers as the most promising photovoltaic devices due to their outstanding power conversion efficiency (PCE) and low-cost. Although the PSC have reached a PCE over 25%, the interface between the perovskite and hole transport layer (HTL) still is a crucial factor limiting higher PCE and long-term stability. In this work, we choose an organic molecule Bis(trifluoromethyl)benzo amide (BTFZA) to passivate defects at the perovskite/HTL interface. Owing to a strong interaction with uncoordinated Pb2+, the BTFZA effectively passivated the surface defects, remarkably promoted carrier transportation. As a result, the perovskite device based on BTFZA surface modification showed a PCE increase of 16.4% over the control device. Especially, the fill factor (FF) and the open-circuit voltage (V OC) of the modified device increased significantly. In addition, the unencapsulated BTFZA-modified device maintains better PCE compared to the control device after aging for over 600 h in ambient air with extreme humidity and temperature conditions. Results suggested that the introduction of BTFZA is an effective way to regulate the surface of perovskite film aiming at highly efficient and stable perovskite solar cells. The successful application of surface passivation strategy can effectively improve the efficiency of perovskite solar cells. [Display omitted] [ABSTRACT FROM AUTHOR]

A Ni 3 S 2 /MnS composite with unique 3-D morphology was synthesized by a novel method consisting of etching and pre-oxidation of Ni foam followed by in situ hydrothermal method. The etching process created a flower-like structure with the Ni foam which was not only used as a substrate but also providing Ni source for subsequent growth of Ni 3 S 2 and Ni 3 S 2 /MnS composite. The synthesized material showed hierarchical structure consisting of porous Ni 3 S 2 which was coated with vertically grown MnS nanorods. The superior morphology enables the access of more active sites in the electrochemical charge/discharge process. In the meantime, the charges involved in redox reaction can be effectively transferred via Ni 3 S 2 with relatively high conductivity to Nickel foam substrate, which improved the availability of MnS. Therefore, when the Ni 3 S 2 /MnS composite was used as a supercapacitor electrode, it showed a remarkable electrochemical performance of 6.70 mAh cm −2 which is over two-fold higher than that of the Ni 3 S 2 (3.15 mAh cm −2 ) and MnS (2.34 mAh cm −2 ) at current density of 2 mA cm −2 , respectively. Impressively, the specific capacity of Ni 3 S 2 /MnS still retained 6.41 mAh cm −2 with the capacity retention of 96.5% even after 1000 cycles. Further, the electrochemical properties of asymmetric supercapacitors (ACSs) deliver a maximum energy density of 0.47 mWh cm −2 at power density of 10 mW cm −2 , together with 82.1% retention after long-term test. [ABSTRACT FROM AUTHOR]

A new nanostructured 3-D honeycomb NiCo 2 S 4 (NC-1) has been successfully prepared by a simple hydrothermal method assisted sulfuration procedure. The morphology of the 3-D honeycomb was investigated by FESEM and TEM, and the results suggest the NC-1 has a highly porous structure. Its chemical composition was characterized by XRD and XPS and the results indicate that the NC-1 is the pure phase of NiCo 2 S 4 . In order to study the effect of morphology on the electrochemical performance, we have also prepared needle-, flake- and petal-like nanostructured NiCo 2 S 4 on Ni foam. When they were used as supercapacitor electrodes, the NC-1 exhibited the highest electrochemical performance among these four kinds of electrodes. Its maximum specific capacity was over 14 mAh cm −2 at 1 mA m −2 and it still yielded 7.96 mAh cm −2 even at 50 mA cm −2 . The NC-1 remained 99.64% of the initial capacity after the long-term test of 1000 cycles. Consequently, the NC-1 has the promising potential as an energy storage system in the future and it can also be used as an ideal substrate for other active materials involving a faradaic process. [ABSTRACT FROM AUTHOR]

Doping a hybrid perovskite semiconductor with metal elements offers an effective means of adjusting its photoelectric properties. To give one example, it has been found that adding lanthanide elements such as Europium (Eu) and Samarium (Sm) into a perovskite layer enhances the photovoltaic performance and photothermal stability of perovskite solar cells. In this study, we therefore added different Praseodymium (Pr)/Lead (Pb) ratios from 0% to 1% to perovskite films in a precursor solution of tri-cation perovskite. We found the photoelectric properties and device performance of perovskite solar cells doped with 0.25% Praseodymium ion (Pr3+) to be significantly improved, with a champion power conversion efficiency (PCE) of 18.56% obtained. Furthermore, the stability of perovskite solar cells (PSCs) with 0.25% Pr3+ doping improved effectively. Overall, with Pr3+ doping, the carrier mobility was dramatically enhanced, and the carrier recombination effectively hindered. These results therefore indicate that Pr3+ doping causes the perovskite to produce lattice shrinkage. As such, the findings shed light on a fresh dopant engineering tactic for fabricating high performance perovskite solar cells. [Display omitted] • Via praseodymium ions (Ⅲ) doping, the perovskite film exhibited excellently enhanced carrier extraction ability. • The PCE of praseodymium chloride doped PSC were improved with better fill factor. • The stability of PSCs was greatly improved by praseodymium ions (Ⅲ) doping. [ABSTRACT FROM AUTHOR]