Highly crystalline SnO2 is demonstrated to serve as a stable and robust electron‐transporting layer for high‐performance perovskite solar cells. Benefiting from its high crystallinity, the relatively ...thick SnO2 electron‐transporting layer (≈120 nm) provides a respectable electron‐transporting property to yield a promising power conversion efficiency (PCE)(18.8%) Over 90% of the initial PCE can be retained after 30 d storage in ambient with ≈70% relative humidity.
A low‐bandgap (1.33 eV) Sn‐based MA0.5FA0.5Pb0.75Sn0.25I3 perovskite is developed via combined compositional, process, and interfacial engineering. It can deliver a high power conversion efficiency ...(PCE) of 14.19%. Finally, a four‐terminal all‐perovskite tandem solar cell is demonstrated by combining this low‐bandgap cell with a semitransparent MAPbI3 cell to achieve a high efficiency of 19.08%.
All-inorganic perovskite solar cells (PVSCs) have drawn increasing attention because of their outstanding thermal stability. However, their performance is still inferior than the typical ...organic-inorganic counterparts, especially for the devices with p-i-n configuration. Herein, we successfully employ a Lewis base small molecule to passivate the inorganic perovskite film, and its derived PVSCs achieved a champion efficiency of 16.1% and a certificated efficiency of 15.6% with improved photostability, representing the most efficient inverted all-inorganic PVSCs to date. Our studies reveal that the nitrile (C-N) groups on the small molecule effectively reduce the trap density of the perovskite film and thus significantly suppresses the non-radiative recombination in the derived PVSC by passivating the Pb-exposed surface, resulting in an improved open-circuit voltage from 1.10 V to 1.16 V after passivation. This work provides an insight in the design of functional interlayers for improving efficiencies and stability of all-inorganic PVSCs.
Low‐temperature, solution‐processable Cu‐doped NiOX (Cu:NiOx), prepared via combustion chemistry, is demonstrated as an excellent hole‐transporting layer (HTL) for thin‐film perovskite solar cells ...(PVSCs). Its good crystallinity, conductivity, and hole‐extraction properties enable the derived PVSC to have a high power conversion efficiency (PCE) of 17.74%. Its general applicability for various elecrode materials is also revealed.
Recently, the evolved intermediate phase based on iodoplumbate anions that mediates perovskite crystallization has been embodied as the Lewis acid–base adduct formed by metal halides (serve as Lewis ...acid) and polar aprotic solvents (serve as Lewis base). Based on this principle, it is proposed to constitute efficient Lewis acid–base adduct in the SnI2 deposition step to modulate its volume expansion and fast reaction with methylammonium iodide (MAI)/formamidinium iodide (FAI) (FAI is studied hereafter). Herein, trimethylamine (TMA) is employed as the additional Lewis base in the tin halide solution to form SnY2–TMA complexes (Y = I−, F−) in the first‐step deposition, followed by intercalating with FAI to convert into FASnI. It is shown that TMA can facilitate homogeneous film formation of a SnI2 (+SnF2) layer by effectively forming intermediate SnY2–TMA complexes. Meanwhile, its relatively larger size and weaker affinity with SnI2 than FA+ ions will facilitate the intramolecular exchange with FA+ ions, thereby enabling the formation of dense and compact FASnI3 film with large crystalline domain (>1 µm). As a result, high power conversion efficiencies of 4.34% and 7.09% with decent stability are successfully accomplished in both conventional and inverted perovskite solar cells, respectively.
High‐performance FASnI3 perovskite solar cells (PVSCs) are realized for the first time by a two‐step deposition technique. Trimethylamine (TMA) is used as an additive to improve the morphology, enabling a dense and compact FASnI3 film with large crystalline domains (>1 μm). Consequently, high PCEs of 4.34% and 7.09% can be successfully realized in both conventional and inverted PVSCs with improved stability.
A one‐step core/shell electrospinning technique is exploited to fabricate uniform luminous perovskite‐based nanofibers, wherein the perovskite and the polymer are respectively employed in the core ...and the outer shell. Such a coaxial electrospinning technique enables the in situ formation of perovskite nanocrystals, exempting the needs of presynthesis of perovskite quantum dots or post‐treatments. It is demonstrated that not only the luminous electrospun nanofibers can possess color‐tunability by simply tuning the perovskite composition, but also the grain size of the formed perovskite nanocrystals is largely affected by the perovskite precursor stoichiometry and the polymer solution concentration. Consequently, the optimized perovskite electrospun nanofiber yields a high photoluminescence quantum yield of 30.9%, significantly surpassing the value of its thin‐film counterpart. Moreover, owing to the hydrophobic characteristic of shell polymer, the prepared perovskite nanofiber is endowed with a high resistance to air and water. Its photoluminescence intensity remains constant while stored under ambient environment with a relative humidity of 85% over a month and retains intensity higher than 50% of its initial intensity while immersed in water for 48 h. More intriguingly, a white light‐emitting perovskite‐based nanofiber is successfully fabricated by pairing the orange light‐emitting compositional perovskite with a blue light‐emitting conjugated polymer.
Uniform luminous perovskite nanofibers prepared by a one‐step core/shell electrospinning technique are demonstrated herein. The optimized perovskite electrospun nanofiber yields a high photoluminescence quantum yield with improved stability. Finally, a white light‐emitting perovskite‐based nanofiber is also successfully fabricated by pairing the orange light‐emitting compositional perovskite with a blue light‐emitting conjugated polymer.
Metal–organic framework (MOF) solids with their variable functionalities are relevant for energy conversion technologies. However, the development of electroactive and stable MOFs for ...electrocatalysis still faces challenges. Here, a molecularly engineered MOF system featuring a 2D coordination network based on mercaptan–metal links (e.g., nickel, as for Ni(DMBD)‐MOF) is designed. The crystal structure is solved from microcrystals by a continuous‐rotation electron diffraction (cRED) technique. Computational results indicate a metallic electronic structure of Ni(DMBD)‐MOF due to the Ni–S coordination, highlighting the effective design of the thiol ligand for enhancing electroconductivity. Additionally, both experimental and theoretical studies indicate that (DMBD)‐MOF offers advantages in the electrocatalytic oxygen evolution reaction (OER) over non‐thiol (e.g., 1,4‐benzene dicarboxylic acid) analog (BDC)‐MOF, because it poses fewer energy barriers during the rate‐limiting *O intermediate formation step. Iron‐substituted NiFe(DMBD)‐MOF achieves a current density of 100 mA cm−2 at a small overpotential of 280 mV, indicating a new MOF platform for efficient OER catalysis.
Molecular design and crystal engineering strategy are applied to construct thiol‐functionalized metal–organic frameworks (MOFs). This MOF platform is successfully decorated with nickel–sulfur links cooperating in the network. The prepared 2D MOF with enhanced electro‐conductivity and modified electronic structure demonstrates superior activity and robust stability toward the oxygen evolution reaction (OER), which paves the way to design MOFs at a molecular level.
Although organic–inorganic hybrid perovskite solar cells (PVSCs) have achieved dramatic improvement in device efficiency, their long‐term stability remains a major concern prior to commercialization. ...To address this issue, extensive research efforts are dedicated to exploiting all‐inorganic PVSCs by using cesium (Cs)‐based perovskite materials, such as α‐CsPbI3. However, the black‐phase CsPbI3 (cubic α‐CsPbI3 and orthorhombic γ‐CsPbI3 phases) is not stable at room temperature, and it tends to convert to the nonperovskite δ‐CsPbI3 phase. Here, a simple yet effective approach is described to prepare stable black‐phase CsPbI3 by forming a heterostructure comprising 0D Cs4PbI6 and γ‐CsPbI3 through tuning the stoichiometry of the precursors between CsI and PbI. Such heterostructure is manifested to enable the realization of a stable all‐inorganic PVSC with a high power conversion efficiency of 16.39%. This work provides a new perspective for developing high‐performance and stable all‐inorganic PVSCs.
A 0D Cs4PbI6/3D CsPbI3 heterostructure is achieved by tuning the stoichiometry of the precursors. The coexistent Cs4PbI6 not only reduces the grain size of the CsPbI3 and serves as a molecular lock to stabilize the black‐phase CsPbI3, but also passivates the defects in the grain boundaries and improves the surface coverage to improve the device performance to 16.39%.
Despite the breakthrough of over 22% power conversion efficiency demonstrated in organic–inorganic hybrid perovskite solar cells (PVSCs), critical concerns pertaining to the instability and toxicity ...still remain that may potentially hinder their commercialization. In this study, a new chemical approach using environmentally friendly strontium chloride (SrCl2) as a precursor for perovskite preparation is demonstrated to result in enhanced device performance and stability of the derived hole‐conductor‐free printable mesoscopic PVSCs. The CH3NH3PbI3 perovskite is chemically modified by introducing SrCl2 in the precursor solution. The results from structural, elemental, and morphological analyses show that the incorporation of SrCl2 affords the formation of CH3NH3PbI3(SrCl2)x perovskites endowed with lower defect concentration and better pore filling in the derived mesoscopic PVSCs. The optimized compositional CH3NH3PbI3(SrCl2)0.1 perovskite can substantially enhance the photovoltaic performance of the derived hole‐conductor‐free device to 15.9%, outperforming the value (13.0%) of the pristine CH3NH3PbI3 device. More importantly, the stability of the device in ambient air under illumination is also improved.
A new compositional perovskite, CH3NH3PbI3(SrCl2)0.1 with more compact morphology and lower defect concentration is presented. Consequently, a power conversion efficiency of 15.9% with enhanced stability is achieved by employing the structure of hole‐conductor‐free fully printable mesoscopic perovskite solar cell.
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