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Interfacial lattice mismatch and adverse reaction are the key issues hindering the development of nickel oxide (NiOx)‐based inverted perovskite solar cells (PVSCs). Herein, a p‐chlorobenzenesulfonic acid (CBSA) self‐assembled small‐molecule (SASM) is adopted to anchor NiOx and perovskite crystals to endow dual‐passivation. The chlorine terminal of SASMs can provide growth sites for perovskite, leading to interfacial strain release. Meanwhile, the sulfonic acid group from SASMs can passivate surface defects of NiOx, conducive to charge carrier extraction. In addition, the self‐assembled layer inhibits the adverse interfacial reaction by preventing NiOx contact with perovskite. Therefore, the NiOx/CBSA‐based PVSCs obtain a champion power conversion efficiency (PCE) of 21.8%. Of particular note, the unencapsulated devices can retain above 80% of their initial PCE values after storage in a nitrogen atmosphere for 3000 h, in air with a relative humidity of 50–70% for 1000 h, and heating at 85 °C for 800 h, respectively. [ABSTRACT FROM AUTHOR]

The buried interface has important effect on carrier extraction and nonradiative recombination of perovksite solar cells (PSCs). Herein, to inactivate the buried interfacial defects of perovskite and boost the crystallization quality of perovskite film, 3‐amino‐1‐adamantanol (AAD) serves as a pre‐buried interface modifier on nickel oxide (NiOx) surface to regulate the nucleation and crystallization process of perovskite precursor. The amino and hydroxyl groups in AAD molecule can synchronously coordinate with nickel ion (Ni3+) in NiOx and lead ion in perovskite, respectively. The dual action favors the ordered arrangement of AAD molecules between NiOx and perovskite, which not only enhances hole extraction in hole transport layer, but also provides active sites for homogeneous nucleation. Furthermore, AAD modifier blocks the unfavorable reaction between Ni3+ and perovskite, and effectively passivates the buried interfacial defects. The optimal inverted PSCs achieve a champion power conversion efficiency of 22.21% with negligible hysteresis, favorable thermal, optical, and long‐term stability. Thus, this strategy of modulating perovskite nucleation and crystallization by pre‐buried modifier is feasible for achieving efficient and stable inverted perovskite solar cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interfacial redox reaction between NiO x and perovskite is obstructed. • SaC-100 is developed as a modifier layer in NiO x -based perovskite solar cells. • SaC-100 can efficiently reduce the open-circuit voltage loss of device. • SaC-100 can inhibit perovskite decomposition ascribed from interfacial reaction. In NiO x -based perovskite solar cells (PVSCs), the interfacial redox reaction between Ni3+ (on the surface of NiO x) and A-site cation salt (MAI in perovskite precursor solution) is invariably ignored. This adverse reaction will generate PbI 2 -rich hole extraction barriers at the NiO x -perovskite interface, which limits hole transmission and increases charge recombination, thus resulting in open-circuit voltage (V oc) loss. Furthermore, it will accelerate perovskite degradation by deprotonating the precursor amine and oxidizing iodide to interstitial iodine, which induces the severe instability of devices. Herein, a physical separation strategy by introducing a modifier layer to obstruct the detrimental reaction is explored. The results demonstrate that the trimethylolpropane tris(2-methyl-1-aziridinepropionate) (SaC-100) depositing onto NiO x can suppress the reaction between Ni3+ and MAI to endow the improvement of conductivity and reduction of interfacial defects, thus reducing V oc loss and enhancing device stability. Moreover, the interfacial energy level alignment and the morphology of perovskite are also optimized. As a result, the PVSCs device based on NiO x /SaC-100 presents the best power conversion efficiency (PCE) of 20.21% with a superior V oc value of 1.12 V. Furthermore, the device shows better light and thermal stability because of the hindering effect and defect passivation effect of SaC-100. [ABSTRACT FROM AUTHOR]

The elimination of methylammonium (MA) cation from mixed tin–lead (Sn–Pb) narrow‐bandgap (NBG) perovskites is an effective approach to enhance the operational stability of all‐perovskite tandem solar cells (TSCs). Unfortunately, the uncontrolled nucleation and crystallization processes of MA‐free Sn–Pb perovskites usually lead to inferior film quality and device performance. Herein, a bimolecular crystallization modulation strategy is reported by using guanidine thiocyanate (GuaSCN) and aminoacetamide hydrochloride (AHC) together as additives to improve the film quality of MA‐free Sn–Pb perovskites. It is demonstrated that the use of bimolecular additives can effectively improve the crystallinity, increase the grain size, and induce a preferred (100) orientation for the corresponding films, leading to high‐quality absorber with considerably reduced defect density and suppressed non‐radiative recombination. In addition, the bimolecular additives can reduce the self‐p‐doping hole concentration within the perovskite films and enhance the charge extraction at the perovskite/electron transport layer interface. The modified NBG perovskite solar cells deliver a power conversion efficiency (PCE) of 22.14%. Coupled with the wide‐bandgap (WBG) subcell, the all‐perovskite TSCs give a champion certified PCE of 27.15%, which is the highest certified PCE for MA‐free all‐perovskite TSCs. Encapsulated tandem devices maintain 90% of the initial PCE after 473 h operation. [ABSTRACT FROM AUTHOR]

Lead‐free 2D antimony‐based halide perovskites with excellent optoelectronic properties, low toxicity, and good intrinsic stability are promising for photovoltaic devices. However, the power conversion efficiency (PCE) of antimony‐based perovskite solar cells (PSCs) is still lower than 3% due to the poor crystallinity and random orientation. Herein, it is found that the Cs3Sb2ClxI9‐x films prepared by adding methylamine chloride as an additive to the precursor solution can form a mixed intermediate phase with 0D dimer phase and 2D layered phase after low pressure treatment. During the annealing process, the 0D dimer phase will completely transition to 2D layered phase due to the partial replacement of I by Cl. Compared to adding SbCl3 directly, this method considerably increases the crystallinity of Cs3Sb2IxCl9‐x films. The obtained films have a preferential orientation along the (201) direction, which is beneficial for charge carrier transportation. Consequently, the champion device shows a PCE of 3.2%, which is one of the highest efficiencies achieved for inorganic Sb‐based PSCs with the n‐i‐p architecture to date. [ABSTRACT FROM AUTHOR]

Oxygen sensors, using organic-inorganic and all-inorganic lead halide perovskites, have demonstrated huge advantages in operating temperature, responding time, and reversing oxygen content detection. Nevertheless, the toxicity and instability issues hinder their wide application. In this work, for the first time, we report a sensitive fluorescence oxygen detector based on lead-free double perovskite Cs 2 AgBiBr 6 thin film. The sensor has a remarkable performance in terms of fast response time of ≈56 s, recovery time of ≈91 s, and a relatively low limit of detection (LOD) of 150 ppm. More importantly, the unencapsulated sensor still exhibits an obvious response at low oxygen concentrations after two-week storage in ambient, and the device also exhibits good humidity, light, and thermal stability. Consequently, the lead-free double perovskite (Cs 2 AgBiBr 6) will be promising environmentally friendly material in developing reversible, sensitive, high-efficiency, and stable perovskite oxygen sensors. [ABSTRACT FROM AUTHOR]

Organic–inorganic metal halide perovskites have recently attracted enormous interest in the field of resistive switching memories owing to their unique electrical properties. Unfortunately, two challenges, the inadequate long-term stability and the toxicity of lead, largely hinder their further practical application. Herein, a 1D all-inorganic lead-free CsCu2Br3 perovskite is proposed for resistive switching devices to resolve these issues. The CsCu2Br3-based resistive switching devices exhibit typical bipolar resistive switching behavior with low set voltage, high on/off ratio (103), stable retention properties (>2 × 104 s), and endurance (200 cycles) in air. The unencapsulated CsCu2Br3-based device still maintains resistive switching characteristics while stored in ambient environment for over 2 months. Moreover, four on-state multilevel information storage behavior has been observed by regulating the value of compliance current during set process. The resistive switching behavior is dominated by the formation and fracture of conductive filaments, which are induced by the movement of Br − ions under electrical bias. This work offers the opportunity and strategy for the design of air-stable and environment-friendly metal halide perovskite-based memory devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) perovskite materials show enormous potential in optoelectronic applications owing to their exceptional thermal stability and unique lattice structures. However, research into anion-substituted 2D perovskites is relatively rare, particularly in the photoelectric information storage field. Here, an anion-based 2D perovskite Cs 2 Pb(SCN) 2 I 2 film with high orientation and high thermal-stability is achieved by simple low-temperature solution processing and the memristor of Al/Cs 2 Pb(SCN) 2 I 2 /FTO is established. The experimental evidence shows that: 1) In the absence of light irradiation, memristors present typical bipolar resistance switching behaviour with On/Off resistance ratio (>103) and reliable retention (>104 s); 2) By introducing light irradiation, it can achieve a more dependable memristor with decreased RS fluctuation and improved cycling endurance. In addition, by modifying the compliance current (I cc), it can realize multi-level storage function of memories with good high temperature endurance. Finally, the logic gate function is also demonstrated with these cells. The operational principles of memristor devices are comprised of the charge trapping and conductive filament mechanisms. The light irradiation reduces the ion migration barrier and enhances the conductivity of perovskite films, thus limiting the excessive growth of conductive filaments. This work offers the groundwork for creating anionic two-dimensional perovskite photoelectric memristor devices. [ABSTRACT FROM AUTHOR]

Tin‐based halide perovskites attract incremental attention due to the favorable optoelectronic properties and ideal bandgaps. However, the poor crystalline quality is still the biggest challenge for further progress in tin‐based perovskite solar cells (PVSCs) due to the unfavorable defects and uncontrollable crystallization kinetics. Here, acetic acid (HAc) is first introduced to reduce the supersaturated concentration of the precursor solution to preferentially form pre‐nucleation clusters, thus inducing rapid nucleation for effective regulation of crystallization kinetics. In particular, the hydrogen ion and acetate ion contained in HAc can effectively inhibit the oxidation of Sn2+, and the hydrogen bonding interaction between HAc and iodide ion (I‐) greatly reduces the loss of I‐, which guarantees the I‐/Sn2+ stoichiometric ratio of the corresponding perovskite film close to theoretical value, thus effectively reducing the defect density and maintaining the perfect crystal lattice. Consequently, the HAc‐assisted tin‐based PVSCs achieve a champion power conversion efficiency of 12.26% with superior open‐circuit voltage up to 0.75 V. Moreover, the unencapsulated device maintains nearly 90% of the initial PCE even after 3000 h storage in nitrogen atmosphere. This demonstrated strategy enables to prepare high‐quality tin‐based perovskite film with lower defect density and lattice distortion. [ABSTRACT FROM AUTHOR]

Tin‐based halide perovskites attract incremental attention due to the favorable optoelectronic properties and ideal bandgaps. However, the poor crystalline quality is still the biggest challenge for further progress in tin‐based perovskite solar cells (PVSCs) due to the unfavorable defects and uncontrollable crystallization kinetics. Here, acetic acid (HAc) is first introduced to reduce the supersaturated concentration of the precursor solution to preferentially form pre‐nucleation clusters, thus inducing rapid nucleation for effective regulation of crystallization kinetics. In particular, the hydrogen ion and acetate ion contained in HAc can effectively inhibit the oxidation of Sn2+, and the hydrogen bonding interaction between HAc and iodide ion (I‐) greatly reduces the loss of I‐, which guarantees the I‐/Sn2+ stoichiometric ratio of the corresponding perovskite film close to theoretical value, thus effectively reducing the defect density and maintaining the perfect crystal lattice. Consequently, the HAc‐assisted tin‐based PVSCs achieve a champion power conversion efficiency of 12.26% with superior open‐circuit voltage up to 0.75 V. Moreover, the unencapsulated device maintains nearly 90% of the initial PCE even after 3000 h storage in nitrogen atmosphere. This demonstrated strategy enables to prepare high‐quality tin‐based perovskite film with lower defect density and lattice distortion. [ABSTRACT FROM AUTHOR]

The effects from the molecular configuration of diammonium spacer cations on 2D/3D perovskite properties are still unclear. Here, we investigated systematically the mechanism of molecular configuration‐induced regulation of crystallization kinetic and carrier dynamics by employing various diammonium molecules to construct Dion‐Jacobson (DJ)‐type 2D/3D perovskites to further facilitating the photovoltaic performance. The minimum average Pb‐I‐Pb angle leads to the smallest octahedral tilting of [PbX6]4− lattice in optimal diammonium molecule‐incorporated DJ‐type 2D/3D perovskite, which enables suitable binding energy and hydrogen‐bonding between spacer cations and inorganic [PbX6]4− cages, thus contributing to the formation of high‐quality perovskite film with vertical crystal orientation, mitigatory lattice distortion and efficient carrier transportation. As a consequence, a dramatically improved device efficiency of 22.68 % is achieved with excellent moisture stability. [ABSTRACT FROM AUTHOR]

The effects from the molecular configuration of diammonium spacer cations on 2D/3D perovskite properties are still unclear. Here, we investigated systematically the mechanism of molecular configuration‐induced regulation of crystallization kinetic and carrier dynamics by employing various diammonium molecules to construct Dion‐Jacobson (DJ)‐type 2D/3D perovskites to further facilitating the photovoltaic performance. The minimum average Pb‐I‐Pb angle leads to the smallest octahedral tilting of [PbX6]4− lattice in optimal diammonium molecule‐incorporated DJ‐type 2D/3D perovskite, which enables suitable binding energy and hydrogen‐bonding between spacer cations and inorganic [PbX6]4− cages, thus contributing to the formation of high‐quality perovskite film with vertical crystal orientation, mitigatory lattice distortion and efficient carrier transportation. As a consequence, a dramatically improved device efficiency of 22.68 % is achieved with excellent moisture stability. [ABSTRACT FROM AUTHOR]

Cs2AgBiBr6 double perovskite nanocrystals (NCs) are materials within the halide perovskite family with promising application potential, owing to their nontoxicity and excellent stability. Herein, Cs2AgBiBr6 NCs were synthesized and their photo-physical properties were investigated in detail. The temperature-dependent photoluminescence (PL) test confirms that their PL mechanism is dependent on the competition between the PL originating from carrier recombination in the conduction band and that in the self-trapping states. Their carrier recombination constants (involving the monomolecular, bimolecular, and Auger recombination rate constants) were obtained from transient absorption data and indicated that the monomolecular recombination decreases with the lowering of temperature, while the bimolecular and Auger recombination show opposite trends. The nonlinear optical properties were studied based on the Z-scan technique, with a two-photon absorption cross section of approximately 1906 GM. Our results suggest that Cs2AgBiBr6 NCs can be extensively applied in the field of optoelectronics, and conventional electronic switches will benefit from the excellent carrier dynamics and nonlinear optical properties. [ABSTRACT FROM AUTHOR]