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Cs2AgBiBr6, as a benchmark lead‐free double perovskite, has emerged as a promising alternative to lead‐based perovskites because of its high stability, non‐toxicity, exceptional optoelectronic properties, and multifunctionality. To encourage further research on Cs2AgBiBr6 and its broad applications, in this review, its fundamental properties including the structure‐property relation, synthesis, stability, origin of absorption and photoluminescence, electron‐phonon coupling, role of defects, charge carrier dynamics, and bandgap modulation are comprehensively emphasized. The recent progress on the wide applications including solar cells, light/X‐ray detectors, and ferroelectric/magnetic devices are highlighted. Moreover, the challenges of Cs2AgBiBr6 materials and related applications are discussed and perspectives are provided for guiding the future development of this research area. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiOx) is desirable hole selective material (HSMs) for perovskite photovoltaics because of the characteristic in stability and low cost. However, they deliver limited open‐circuit voltage (VOC) compared to some organic HSMs. As it is known, the performance of perovskite solar cells is predominantly limited by trap‐assisted non‐radiative recombination at the perovskite/hole‐selective layer interfaces. A typical lithium‐doping strategy leads to the valence‐band maximum shift and the electronic levels of NiOx can be tuned robustly to match perovskite active layer in perovskite solar cells. More critically, carrier dynamics studies demonstrate another critical PN4N interlayer strategy reduced interfacial density of defect sites and trap‐assisted recombination. These merits contribute coordinately to lower energy loss across the perovskite/NiOx interface and facilitate charge transport process through the relevant interface, yielding VOC values increase to 1.14 V and power conversion efficiencies over 20%. [ABSTRACT FROM AUTHOR]

Tin (Sn) is a potential replacement for lead in organic–inorganic perovskite solar cell (PVSC) technology due to the attractive optoelectronic properties of Sn-perovskites. However, the poor stability of Sn2+ ions is still the main hindrance for achieving highly stable and efficient Sn-based PVSCs. In this work, anilinium hypophosphite (AHP) is introduced as a co-additive into a Sn-absorber perovskite precursor containing the tin fluoride (SnF2) additive. The incorporation of the AHP additive not only prohibits the phase separation of SnF2 but also passivates the perovskite films and finally results in absorbers with superior structural and optoelectronic properties. The underlying reason is related to the formation of a double-salt complex (Sn(H2PO2)2·SnF2) through the interaction between AHP and SnF2. The high quality of the absorber film induced by AHP delivers an improved device power conversion efficiency (PCE) with a higher open-circuit voltage than those without the AHP additive. More importantly, the device with the AHP additive can retain up to 97% of its PCE after 30 days of storage in a glovebox. [ABSTRACT FROM AUTHOR]

[Display omitted] • Anilinium hypophosphite was used as a co-additive in FASnI 3 perovskite. • Anilinium hypophosphite improved the perovskite optoelectronic properties. • Enhanced photovoltaic performance was obtained using new additive. Tin (Sn) is a promising substitute for lead (Pb) in organic–inorganic hybrid halide perovskite-photovoltaic devices, but it is prone to delivering low power conversion efficiencies (PCEs) due to the poor quality of Sn-perovskite films. In this work, anilinium hypophosphite (AHP) co-additive is used to fabricate high-quality FASnI 3 (FA+: formamidinium) perovskite films with suppressed phase-segregation and prolonged charge carrier lifetime. Perovskite films containing 0.05 M AHP are used to fabricate solar cells and deliver improved power conversion efficiency (PCE) of up to 5.48% (control devices: 4.04%). AHP eliminates the phase separation caused by SnF 2 in the absorber, leading to films with enhanced optoelectronic properties, hence the high performance of AHP-based devices. [ABSTRACT FROM AUTHOR]

Perovskite Solar Cells: In Situ Defect Passivation with Silica Oligomer for Enhanced Performance and Stability of Perovskite Solar Cells (Adv. In article number 1901716, Hongwei Lei, Song Zhang, Zuojun Tan, and co-workers report a novel and efficient perovskite defect passivation strategy using silica oligomer. Silica oligomer PA can enlarge perovskite grain sizes, prolong carrier lifetime, enhance charge carrier dynamics and reduce trap state densities, resulting in highly efficient PVSCs with good humid and thermal stability. [Extracted from the article]

Perovskite solar cells (PVSCs) have achieved excellent power conversion efficiency (PCE) but still suffer from instability issues. Defect passivation is an important route to simultaneously increase the efficiency and stability of PVSCs. Here, a strategy of incorporating silica oligomer in perovskite films for surface and grain boundary defect passivation is reported. Silica oligomer passivation agent (PA) is in situ formed through hydrolysis and condensation reaction of tetraethyl orthosilicate additive in perovskite precursor. The passivation mechanism is elucidated by density functional theory calculation, revealing stable chelating interaction and hydrogen bond interaction between PA and perovskite. Spectroscopic and electrical characterizations demonstrate that silica oligomer can enlarge grain sizes, prolong carrier lifetime, enhance charge carrier dynamics, and reduce trap state densities in perovskite films. Planar PVSCs with passivation achieve a highly improved PCE of 19.64% with a stabilized efficiency of 18.81%. More importantly, unencapsulated perovskite devices with passivation retain nearly 90% of original efficiency after 1000 h storage under ambient condition and sustained 87% of initial performance after high‐temperature (120 °C) thermal accelerated aging, showing highly enhanced moisture and thermal stability. Therefore, the present study provides a pathway to the future design and optimization of PVSCs with higher efficiency and greater stability. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have developed rapidly in recent years as the third generation solar cells. In spite of the great improvement achieved, there still exist some issues such as undesired hysteresis and indispensable high temperature process. In this work, bulk heterojunction perovskite-phenyl-C 61 -butyric acid methyl ester solar cells have been prepared to diminish hysteresis using a facile two step spin-coating method. Furthermore, high quality tin oxide films are fabricated using pulse laser deposition technique at room temperature without any annealing procedure. The as fabricated tin oxide film is successfully applied in bulk heterojunction perovskite solar cells as a hole blocking layer. Bulk heterojunction devices based on room temperature tin oxide exhibit almost hysteresis-free characteristics with power conversion efficiency of 17.29% and 14.0% on rigid and flexible substrates, respectively. [ABSTRACT FROM AUTHOR]

Ternary oxides Fe 2-x Mg x O 3 is introduced to passivate the perovskite/SnO 2 QDs interface, trigger the heterogeneous nucleation for uniform perovskite films, and increase the interface contact for the rapid electron transfer. Consequently, the corresponding perovskite solar cell achieves a champion efficiency over 21%. [Display omitted] • Fe 2-x Mg x O 3 is introduced to passivate the perovskite/SnO 2 interface. • The interaction between perovskite and Fe 2-x Mg x O 3 triggers a heterogeneous nucleation. • Flocculent Fe 2-x Mg x O 3 increase the contact with perovskite for electron transfer. • The interaction between Fe 2-x Mg x O 3 and SnO 2 QD passivates the defects. • Fe 1.84 Mg 0.16O 3 -based PSC achieves a champion efficiency over 21% with negligible J–V hysteresis. Interface function material has been widely used to reduce interfacial potential barrier for enhanced charge-dynamics and photovoltaic properties of perovskite solar cells (PSCs). Herein, ternary oxides Fe 2-x Mg x O 3 are introduced to passivate the perovskite/SnO 2 quantum dots (QDs) interface. The interaction between perovskite and Fe 2-x Mg x O 3 could trigger a heterogeneous nucleation for the uniform perovskite photoactive layer. The flocculent Fe 2-x Mg x O 3 also increase the interface contact with perovskite enabling more transferring channel of electron, and decrease the interface-defects with smaller the energy level offset at this interface. Such oxide bridges between perovskite and SnO 2 QD could effectively enhance electron transfer. Consequently, a Fe 1.84 Mg 0.16 O 3 -based PSC is achieved with a champion efficiency over 21% and negligible J–V hysteresis. [ABSTRACT FROM AUTHOR]