Search

Hydrazine derivatives have been extensively studied as some of the earliest reductants for Sn–Pb mixed perovskite precursors. However, phenyl hydrazine (BH) as a strong reductant for Sn-based perovskite solutions has not been reported yet, and Sn2+ is unusually oxidized in the precursor solution with BH additives in our experiment. Thus, not all organic reductants are suitable as additives, and therefore selecting a suitable reductant should be paid special attention to. Herein, it is found that BH as a Brønsted base deprotonates MA+ to produce HI, which further catalyzes the oxidation of Sn2+ by DMSO. As an alternative, hydrochloride phenyl hydrazine with a sulfonic amide group (–SO2–NH2) is added to the precursor as a reductant and passivator. As a result, a power conversion efficiency of 22.01% is achieved, and prolonged shelf stability is realized. [ABSTRACT FROM AUTHOR]

Understanding the degradation kinetics of perovskite materials in operating perovskite solar cells (PSCs) is critical for developing methods to further enhance their device stability. However, it remains a challenge to capture the details and characteristics of the perovskite degradation process inside operating PSCs under different environmental conditions in real‐time at the microscopic scale. Herein, a novel, nondestructive real‐time in situ monitoring method based on a tapered seven‐core fiber optic sensor is demonstrated. The fiber‐optic sensor can be facilely inserted near the surface of the perovskite layer of a working PSCs to monitor its degradation kinetics without interfering with the performance of the device. Stable and reproducible correlations between real‐time material degradation and optical wavelength response under different humidity and temperature conditions are observed and quantified. This new measurement tool allows real‐time access to the detailed degradation evolution of PSCs, which not only guides the design of more stable devices but also offers the possibility to monitor the health status of PSCs in field applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Formamidinium (FA)‐based Sn‐Pb perovskite solar cells (FAPb0.5Sn0.5I3 PSCs) with ideal bandgap and impressive thermal stability have caught enormous attention recently. However, it still suffers from the challenge of realizing high efficiency due to the surface imperfections of the transport materials and the energy‐level mismatch between functional contacts. Herein, it is demonstrated that the modification on buried interface with alkali metal salts is a viable strategy to alleviate these issues. We systematically investigate the role of three alkali metal bromide salts (NaBr, KBr, CsBr) by burying them between the NiOx hole transport layer (HTL) and the perovskite light‐absorbing layer, which can effectively passivate interface defects, improve energy‐level matching and release the internal residual strain in perovskite layers. The device with CsBr buffer layer exhibits the best power conversion efficiency (PCE) approaching 20%, which is one of the highest efficiencies for FA‐based Sn‐Pb PSCs employing NiOx HTLs. Impressively, the long‐term storage stability of the unencapsulated device is also greatly boosted. Our work provides an efficient strategy to prepare desired FA‐based ideal‐bandgap Sn‐Pb PSCs which could be applied in tandem solar cells. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite solar cells (PSCs) are regarded as a promising next‐generation photovoltaic technology. However, poor device stability limits their commercialization. Carbon‐based inorganic PSCs (C‐IPSCs) can meet stability challenge owing to the absence of organic components. Meanwhile, the hydrophobic carbon materials as hole transport layers and back electrodes simplify fabrication process, decrease costs, and protect devices from moisture erosion. Since the first attempt for C‐IPSCs in 2016, a series of strategies have been proposed to improve device performance, including the fabrication technique optimization, solvent engineering, composition engineering, interface engineering, charge transport layer optimization, and so on, and the power conversion efficiency of C‐IPSCs are rapidly increased from initial 5% to exceeding 15%. In this review, the recent progress of C‐IPSCs is summarized, the existing challenges in this field are discussed, followed by a prospect for future development. [ABSTRACT FROM AUTHOR]

We report a solution-processing method to prepare an inorganic LaNiO3 (LNO) hole-transport layer (HTL) under low temperature (<150 °C) for the first time. The inverted PSCs prepared with LNO exhibit high UV-stability and promising efficiency (17.15%). Our preliminary results show great potential for LNO HTL in the fabrication of efficient and photostable inverted perovskite solar cells (PSCs). [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) is an appealing electron transport layer for inorganic perovskite solar cells (IPSCs). However, attempts to achieve high device performance have been undermined by the imperfections at the ZnO/perovskite interface, including the intrinsic defects of ZnO and the nonideal contact between ZnO and perovskite films, which can cause severe interfacial recombination losses. With the purpose of resolving these problems, cesium salts with functional anions of acetate (Ac−), fluoride (F−) and trifluoroacetate (TFA−) are explored to modulate the deposition of ZnO films. It is evidenced that these functional anions can coordinate with both Zn2+ and Pb2+ ions, causing defect passivation of the ZnO and the top perovskite films to different extents. Meanwhile, the Cs+ ions can reduce the hydroxyl defects and form an interfacial dipole on the surface of ZnO via Zn–O–Cs bonds. Therefore, more stable and efficient interfacial electron transport can be established. Accordingly, we obtained a maximum power conversion efficiency (PCE) of 14.25% in low-temperature carbon-based IPSCs (C-IPSCs) using a CsPbI2Br light absorber. This PCE is the highest value among all the ZnO-based C-IPSCs reported to date. Moreover, the corresponding devices without encapsulation demonstrate improved long-term stability in ambient air. [ABSTRACT FROM AUTHOR]

Low band gap tin‐lead perovskite solar cells (Sn−Pb PSCs) are expected to achieve higher efficiencies than Pb‐PSCs and regarded as key components of tandem PSCs. However, the realization of high efficiency is challenged by the instability of Sn2+ and the imperfections at the charge transfer interfaces. Here, we demonstrate an efficient ideal band gap formamidinium (FA)‐based Sn−Pb (FAPb0.5Sn0.5I3) PSC, by manipulating the buried NiOx/perovskite interface with 4‐hydroxyphenethyl ammonium halide (OH‐PEAX, X=Cl−, Br−, or I−) interlayer, which exhibits fascinating functions of reducing the surface defects of the NiOx hole transport layer (HTL), enhancing the perovskite film quality, and improving both the energy level matching and physical contact at the interface. The effects of different halide anions have been elaborated and a 20.53 % efficiency is obtained with OH‐PEABr, which is the highest one for FA‐based Sn−Pb PSCs using NiOx HTLs. Moreover, the device stability is also boosted. [ABSTRACT FROM AUTHOR]

Low band gap tin‐lead perovskite solar cells (Sn−Pb PSCs) are expected to achieve higher efficiencies than Pb‐PSCs and regarded as key components of tandem PSCs. However, the realization of high efficiency is challenged by the instability of Sn2+ and the imperfections at the charge transfer interfaces. Here, we demonstrate an efficient ideal band gap formamidinium (FA)‐based Sn−Pb (FAPb0.5Sn0.5I3) PSC, by manipulating the buried NiOx/perovskite interface with 4‐hydroxyphenethyl ammonium halide (OH‐PEAX, X=Cl−, Br−, or I−) interlayer, which exhibits fascinating functions of reducing the surface defects of the NiOx hole transport layer (HTL), enhancing the perovskite film quality, and improving both the energy level matching and physical contact at the interface. The effects of different halide anions have been elaborated and a 20.53 % efficiency is obtained with OH‐PEABr, which is the highest one for FA‐based Sn−Pb PSCs using NiOx HTLs. Moreover, the device stability is also boosted. [ABSTRACT FROM AUTHOR]

Carbon-based CsPbI2Br perovskite solar cells (PSCs) have attracted widespread attention due to their low cost and superior thermal stability. Unfortunately, the bulk defects and interfacial energy level mismatch limit the improvement of device performance. To solve the above issues, we introduce aromatic phenylethylammonium halides (PEAI and PEABr) and their fluorinated derivatives of 4-fluorophenylethylammonium halides (P-F-PEAI and P-F-PEABr) as a passivation layer to post-treat low-temperature CsPbI2Br films. Benefiting from reduced perovskite defects and better energy level alignments, the charge non-radiative recombination is effectively suppressed, and the hole extraction is promoted. Compared with the reference PSCs, the optimized devices achieve a maximum power conversion efficiency (PCE) of 13.97%. To the best of our knowledge, it should be one of the highest PCEs reported among those of low-temperature carbon-based CsPbI2Br PSCs. In addition, nonencapsulated devices exhibit improved moisture and thermal stability in ambient air. [ABSTRACT FROM AUTHOR]

With the advantages of narrow bandgap and excellent thermal stability, fomamidinium lead triiodide (FAPbI3) perovskite holds the promise to boost the power conversion efficiency (PCE) of perovskite solar cells (PSCs) to over 25%. However, such a promise is blurred by the poor structural stability of the black α‐phase FAPbI3, as it can spontaneously transform into photoinactive δ‐phase at room temperature and this process can be accelerated by the ambient moisture. The incorporation of small ions such as cesium (Cs+), methylammonium (MA), and bromide (Br−) into the perovskite lattice is proven to be successful in stabilizing the α‐phase FAPbI3; however, the resultant mixed perovskites suffer the phase segregation problem, which inevitably undermines the long‐term stability of the corresponding PSCs. Therefore, continuous efforts are made to realize stable and pure‐phase α‐FAPbI3 perovskites. Herein, the recent progress on the development of efficient and stable FAPbI3 PSCs is summarized with a focus on the different phase stabilization strategies. In addition, the challenges and possible directions for future study are proposed. [ABSTRACT FROM AUTHOR]

Carbon‐based inorganic perovskite solar cells (C‐PSCs) have attracted intensive attention owing to their low cost and superior thermal stability. However, the bulk defects in perovskites and interfacial energy level mismatch seriously undermine their performance. To overcome these issues, a multifunctional dual‐interface engineering is proposed with a focus on low‐temperature CsPbI2Br C‐PSCs, where the potassium trifluoroacetate (KTFA) and the 4‐trifluorophenyl methylammonium bromide (CF3PMABr) are introduced beneath and on top of the perovskite layer, respectively. It is found that TFA‐ ions locate at the SnO2/CsPbI2Br interface, whereas a small amount of K+ ions diffuse into perovskite lattice to participate in nucleation and crystallization, resulting in more favored interfacial energy level alignment, improved film quality, passivated interfacial defects, released interfacial strain, as well as suppressed charge recombination and ion migration. Meanwhile, the CF3PMABr passivates I/Br vacancies and forms 2D perovskite capping layer to facilitate hole extraction at the CsPbI2Br/carbon interface. As a result, a remarkable power conversion efficiency (PCE) of 14.05% with an open‐circuit voltage of 1.273 V is achieved. To the best of the authors' knowledge, it is currently the highest PCE reported for low‐temperature CsPbI2Br C‐PSCs. Furthermore, the nonencapsulated device exhibits improved moisture, thermal, and illumination stability in ambient air. [ABSTRACT FROM AUTHOR]

Solution‐processed nickel oxide nanocrystals (NiOx NCs) ink can be facilely applied to deposit NiOx thin films as the hole transport layer (HTL) for perovskite solar cells (PSCs). Both the efficiency and stability of the corresponding PSCs depend significantly on the size and the energy levels of the as‐synthesized NiOx NCs; however, previous studies have shown that these two aspects can be hardly controlled synchronously to maximize the device performance. Herein, a novel synthesis of highly dispersed NiOx NCs is demonstrated by employing tetraalkylammonium hydroxides (TAAOHs, alkyl = methyl, ethyl, propyl, butyl) as precipitating bases, where the varied alkyl chain lengths of TAAOHs enable the size control of the NiOx NCs and the subsequent altering of their Ni3+ contents, leading to tunable energy levels of the NiOx thin films. With the longest butyl chain, the smallest crystal size and the optimal energy level alignment at the NiOx/perovskite interface are achieved. After further passivating the detrimental Ni3+ species on the surface of NiOx HTL, a remarkable power conversion efficiency (PCE) approaching 23% is obtained, which is one of the highest PCEs reported for NiOx‐based inverted PSCs. Furthermore, the unencapsulated device exhibits excellent ultraviolet stability, which maintains ≈87% of its PCE after 200 h exposure. [ABSTRACT FROM AUTHOR]

All-inorganic halide perovskites (IHPs) hold promise in the field of optoelectronics due to their excellent thermal stability. However, the phase instability of these metastable structural polymorphs needs to be addressed. Here, a great deal of interest has been emerging to understand the phase (in)stability and report an additional stability mechanism of CsPbI2Br perovskite induced by both O2 and moisture in dry and high humid air to develop engineering strategies for making more robust IHPs. It is demonstrated that CsPbI2Br prepared in N2 experiences a sharp degradation as it is exposed to air (RH = 35%), while CsPbI2Br prepared in air shows much better long-term stability than that prepared in N2 atmosphere in both low (RH = 5–15%) and high humidity (RH = 30–55%) environments. The participation of O2 in the formation of perovskite crystals to form Pb–O bonds in the spin-coating process can prevent the transformation of CsPbI2Br from the α-phase to the δ-phase. In the presence of both oxygen and moisture, it is suggested that water can stabilize the reactive superoxide, which is formed by oxygen with excess electrons and enable them to spontaneously form additional Pb–O bonds with Pb before annealing. This can further stabilize perovskite under higher humidity conditions and improve the phase stability. This work presents a material design to develop IHPs in air with high stability. [ABSTRACT FROM AUTHOR]

Copper nanowires (CuNWs) are promising electrode materials, especially for used in flexible and transparent electrodes, due to their advantages of earth-abundant, low-cost, high conductivity and flexibility. However, the poor stability of CuNWs against oxidation and chemical corrosion seriously hinders their practical applications. Herein, we propose a facile strategy to improve the chemical stability of CuNWs by in situ coating of carbon protective layer on top of them through hydrothermal carbonization method. The influential factors on the growth of carbon film including the concentration of the glucose precursor (carbon source), hydrothermal temperature, and hydrothermal time are systematically studied. By tailoring these factors, carbon layers with thickness of 3–8 nm can be uniformly grown on CuNWs with appropriate glucose concentration around 80 mg·mL−1, hydrothermal temperature of 160–170°C, and hydrothermal time of 1–3 h. The as-prepared carbon-coated CuNWs show excellent resistance against corrosion and oxidation, and are of great potential to use broadly in various optoelectronic devices. [ABSTRACT FROM AUTHOR]

The realization of highly efficient perovskite solar cells (PSCs) in ambient air is considered to be advantageous for low‐cost commercial manufacturing. However, it is fundamentally difficult to achieve comparable device performance to that obtained in an inert atmosphere, especially when the ambient humidity is high. Here, an effective precursor engineering that simultaneously employs non‐halide lead acetate and lead thiocyanate lead sources for fabricating high‐quality methylammonium lead iodide perovskite films in ambient air with enhanced moisture tolerance, is reported. The presence of Ac– and SCN– ions not only enables the facile formation of homogeneous and highly crystalized perovskite films, but also directs the uniform growth of the crystals along the (110) direction. Accordingly, a 20.55% efficiency is demonstrated, one of the best results for air‐processed MAPbI3 PSCs, which is also the highest value achieved with non‐halide lead sources. Furthermore, the unencapsulated device shows fivefold prolonged air stability (3600 h) compared to the conventional PbI2‐based PSC. Together with the use of non‐toxic antisolvent, this strategy is fully compatible with ambient air operation and thus of great potential for practical applications. [ABSTRACT FROM AUTHOR]

Tin–lead (Sn–Pb) binary low‐bandgap perovskites are more environmentally friendly than conventional Pb‐based perovskites and promise to deliver high photovoltaic performance by constructing tandem solar cells. However, the energy‐level mismatch between functional layers and tremendous trap states in perovskite films make it challenging to reduce the high open‐circuit voltage (Voc) loss in Sn–Pb binary perovskite solar cells (PSCs). Herein, energy loss reduction at the hole collection interface in Sn–Pb binary PSCs is demonstrated using nickel oxide (NiOx) as the hole transport material (HTM) with optimal poly[(9,9‐bis(3′‐(N,N‐dimethylamino)propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctyfluorene)] (PFN) modification, which enables a significantly enhanced Voc compared to the traditional poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)‐based devices. The NiOx/PFN bilayer has a downward‐shifted valence band compared to PEDOT:PSS, providing well‐matched energy‐level alignment with the perovskite material, resulting in more fluent charge transfer and reduced Voc losses. The optimized device has a high Voc of 0.88 V and an efficiency of 19.80%, surpassing the previous results reported for NiOx‐based Sn–Pb PSCs. Moreover, the robust NiOx/PFN substrate and the high‐quality perovskite film grown on it make the device less vulnerable to ambient exposure. This work highlights the significance of ideal hole conductors and interface engineering in efficient and stable Sn–Pb low‐bandgap PSCs. [ABSTRACT FROM AUTHOR]

The development of tin-based perovskite solar cells (PSCs) is a promising approach to meet the demand of eco-friendly, lead-free perovskite photovoltaics. Limited to the poor chemical stability of tin perovskites, tin-based PSCs usually have to be fabricated with an inverted device structure and both the device efficiency and stability are highly dependent on the selection of hole transport materials (HTMs). Here, we report the synthesis of inorganic nickel oxide (NiOx) nanoparticles (NPs) via a soft base precipitation method, which enables us to obtain highly dispersed NiOx NPs over a wide pH window. The as-prepared NiOx NPs are employed as the HTM for formamidinium tin iodide (FASnI3) PSCs, resulting in excellent device efficiency (∼8%) and stability (1200 h). Our study offers a facile strategy for mass production of NiOx NPs and easy access to efficient and robust inorganic HTMs that could further boost the development of high performance tin-based PSCs. [ABSTRACT FROM AUTHOR]

Electron transport materials (ETMs) play a significant role in perovskite solar cells (PSCs). However, conventional solution processable organic ETMs are mainly restricted to fullerene derivatives and it is challenging to obtain nonfullerene ETMs with satisfactory properties. In this work, a new organic semiconductor SPS‐4F is synthesized by utilizing the classical spiro[fluorine‐9′9‐thioxanthene] unit to construct a π‐extended core. Although spiro is normally used in hole transport materials, the new spiro derivative SPS‐4F is successfully used as an ETM in inverted PSCs with power conversion efficiency over 20%. In addition, SPS‐4F can strongly coordinate with MAPbI3 perovskite and lead to efficient surface trap passivation. The resultant PSCs exhibit excellent stability in air because of the hydrophobic property of SPS‐4F. This work opens up opportunities to obtain a new family of ETMs based on spiro and paves a way to the fabrication of high‐performance PSCs with low cost. [ABSTRACT FROM AUTHOR]

As a promising lead-free perovskite candidate, tin-based halide perovskites such as FASnI3 have attracted extensive attention recently in photovoltaic applications. However, the relatively low efficiency and poor long-term stability of tin-based perovskite solar cells hinder their practical applications. Here, ammonium hypophosphite is introduced into the FASnI3 perovskite precursor to suppress the oxidation of Sn2+ and assist the growth of perovskite grains, leading to improved perovskite film quality and reduced defect density, and consequently, the device efficiency and open circuit voltage are substantially improved. More importantly, the solar cells exhibit pronounced enhancement of the long-term stability. This work provides a facile approach for improving the performance of tin-based perovskite solar cells by introducing ammonium hypophosphite as an antioxidant agent in the precursor solution. [ABSTRACT FROM AUTHOR]

Tin‐based perovskites with excellent optoelectronic properties and suitable band gaps are promising candidates for the preparation of efficient lead‐free perovskite solar cells (PSCs). However, it is challenging to prepare highly stable and efficient tin‐based PSCs because Sn2+ in perovskites can be easily oxidized to Sn4+ upon air exposure. Here we report the fabrication of air‐stable FASnI3 solar cells by introducing hydroxybenzene sulfonic acid or its salt as an antioxidant additive into the perovskite precursor solution along with excess SnCl2. The interaction between the sulfonate group and the Sn2+ ion enables the in situ encapsulation of the perovskite grains with a SnCl2–additive complex layer, which results in greatly enhanced oxidation stability of the perovskite film. The corresponding PSCs are able to maintain 80 % of the efficiency over 500 h upon air exposure without encapsulation, which is over ten times longer than the best result reported previously. Our results suggest a possible strategy for the future design of efficient and stable tin‐based PSCs. Protective coating: A tin‐based perovskite solar cell with significantly improved stability to oxidation was prepared by introducing hydroxybenzene sulfonic acid or a salt thereof as an antioxidant additive into the perovskite precursor solution. The resulting perovskite grains are encapsulated by a SnCl2–additive complex layer. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bifacial dye-sensitized solar cells (DSCs) that are able to utilize the incidental light from both their front- and rear-side have received increasing attention in recent years. Compared to conventional DSCs that can only be operated under front-side illumination, bifacial design will allow DSCs to generate up to 50% more electrical power. Besides, bifacial DSCs can be easily made transparent and may find broad applications in building integrated photovoltaics (BIPV) as power-generating windows and roof panels. Transparent counter electrodes (CEs) are key to the fabrication of bifacial DSCs. However, despite the fact that conventional Pt CE can be made transparent, its high cost and scarce source may hinder the large-scale application of DSCs. Therefore, many efforts have been made to develop low-cost alternative CEs based on carbon materials, conducting polymers, inorganic compounds and their composites. In this feature article, we intend to pay special attention to the recent advances in the development of Pt-free transparent CEs and highlight their applications in bifacial DSCs. [ABSTRACT FROM AUTHOR]

Optofluidics may hold the key to greater success of photocatalytic water treatment. This is evidenced by our findings in this paper that the planar microfluidic reactor can overcome the limitations of mass transfer and photon transfer in the previous photocatalytic reactors and improve the photoreaction efficiency by more than 100 times. The microreactor has a planar chamber (5 cm×1.8 cm×100 μm) enclosed by two TiO2-coated glass slides as the top cover and bottom substrate and a microstructured UV-cured NOA81 layer as the sealant and flow input/output. In experiment, the microreactor achieves 30% degradation of 3 ml 3×10-5M methylene blue within 5 min and shows a reaction rate constant two orders higher than the bulk reactor. Under optimized conditions, a reaction rate of 8% s-1 is achieved under solar irradiation. The average apparent quantum efficiency is found to be only 0.25%, but the effective apparent quantum efficiency reaches as high as 25%. Optofluidic reactors inherit the merits of microfluidics, such as large surface/volume ratio, easy flow control, and rapid fabrication and offer a promising prospect for large-volume photocatalytic water treatment. [ABSTRACT FROM AUTHOR]

Electrospinning, a low cost production method for large area nanofibrous films, is employed to fabricate organic-inorganic hybrid solar cells based on poly(3-hexylthiophene) and TiO2nanofibers. The performance of the hybrid solar cells is optimized by modifying the surface of TiO2nanofibers with ruthenium dye (N719) and 3-phenylpropionic acid, which results in the average power conversion efficiency of about 1.1% under AM 1.5G simulated illumination (100 mW cm−2). It is found that the co-modification of N719 and 3-phenylpropionic acid on TiO2can induce more ordered backbone packing of poly(3-hexylthiophene) layer, lower density of trap states on the surface of TiO2and longer lifetime of carriers in the active layer due to retarded recombination process by the modifier. Therefore the interface modification can dramatically enhance the photovoltaic performance. [ABSTRACT FROM AUTHOR]

Electrospinning, a low cost production method for large area nanofibrous films, is employed to fabricate organic-inorganic hybrid solar cells based on poly(3-hexylthiophene) and TiO2nanofibers. The performance of the hybrid solar cells is optimized by modifying the surface of TiO2nanofibers with ruthenium dye (N719) and 3-phenylpropionic acid, which results in the average power conversion efficiency of about 1.1% under AM 1.5G simulated illumination (100 mW cm−2). It is found that the co-modification of N719 and 3-phenylpropionic acid on TiO2can induce more ordered backbone packing of poly(3-hexylthiophene) layer, lower density of trap states on the surface of TiO2and longer lifetime of carriers in the active layer due to retarded recombination process by the modifier. Therefore the interface modification can dramatically enhance the photovoltaic performance. [ABSTRACT FROM AUTHOR]

Electron Transport Materials: -Extended Spiro Core-Based Nonfullerene Electron-Transporting Material for High-Performance Perovskite Solar Cells (Adv. Funct. Keywords: electron transport materials; nonfullerenes; passivation; perovskite solar cells; spiro derivatives EN electron transport materials nonfullerenes passivation perovskite solar cells spiro derivatives 1 1 1 06/22/20 20200618 NES 200618 In article number 2001073, Hong Meng, Feng Yan, and co-workers design, synthesize, and successfully use a non-fullerene electron transport material based on a new spiro derivative, SPS-4F, in perovskite solar cells, leading to high efficiency as well as good stability of the devices. Electron transport materials, nonfullerenes, passivation, perovskite solar cells, spiro derivatives. [Extracted from the article]

Organic–inorganic hybrid perovskites have emerged as promising functional materials for high‐performance photodetectors. However, the toxicity of Pb and the lack of internal gain mechanism in typical perovskites significantly hinder their practical applications. Herein, a low‐voltage and high‐performance photodetector based on a single layer of lead‐free Sn‐based perovskite film is reported. The device shows broadband response from ultraviolet to near‐infrared light with a responsivity up to 105 A W−1 and a high gain at a low operating voltage. The outstanding performance is attributed to the high hole mobility, p‐doping nature, and excellent optoelectronic properties of the Sn‐based perovskite. Moreover, the device is assembled on a flexible substrate and demonstrates both high sensitivity and good bending stability. This work demonstrates a route for realizing nontoxic, low‐cost, and high‐performance perovskite photodetectors with a simple device structure. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that 1,1′-methylene bis(3-n-methylimidazolium) diiodide (MMIDI) can be used as an excellent alternative iodide source to conventional lithium iodide (LiI) in electrolyte for dye-sensitized solar cell (DSSC). The MMIDI is cheaper and shows much improved physical and chemical stability compared to LiI. Noticeably, smaller charge transfer resistance for the reduction of triiodide and longer electron lifetime are found in the DSSCs based on MMIDI electrolyte, which result in a 23% higher overall conversion efficiency (5.26%) than that based on LiI electrolyte (4.27%). When the initial MMIDI electrolyte is optimized with functional additives, a promising 6.24% conversion efficiency is achieved. [ABSTRACT FROM AUTHOR]