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In addition to high efficiencies, upscaling and long‐term operational stability are key pre‐requisites for moving perovskite solar cells toward commercial applications. In this work, a strategy to fabricate large‐area uniform and dense perovskite films with a thickness over one‐micrometer via a two‐step coating process by introducing NH4Cl as an additive in the PbI2 precursor solution is developed. Incorporation of NH4Cl induces the formation of the intermediate phases of x[NH4+]·[PbI2Clx]x− and HPbI3−xClx, which can effectively retard the crystallization rate of perovskite leading to uniform and compact full‐coverage perovskite layers across large areas with high crystallinity, large grain sizes, and small surface roughness. The 5 × 5 and 10 × 10 cm2 perovskite solar modules (PSMs) based on this method achieve a power conversion efficiency (PCE) of 14.55% and 10.25%, respectively. These PSMs also exhibit good operational stability with a T80 lifetime (the time during which the solar module PCE drops to 80% of its initial value) under continuous light illumination exceeding 1600 h (5 × 5 cm2) and 1100 h (10 × 10 cm2), respectively. [ABSTRACT FROM AUTHOR]

Lead-free double perovskite materials have attracted much interest for optoelectronic applications due to their nontoxicity and high stability. In this work, centimetre-sized Cs2AgBiBr6 single crystals were successfully grown using methylammonium bromide (MABr) as the flux by a top-seeded solution growth (TSSG) method. The low-temperature crystal structure of Cs2AgBiBr6 single crystals was determined and refined. To investigate the interface problems between Cs2AgBiBr6 single crystals and electrodes, the optical band gap, X-ray photoelectron spectroscopy (XPS), and ultraviolet photoemission spectroscopy (UPS) measurements were performed on Cs2AgBiBr6 single crystals. More importantly, we investigated the photodetectors based on Cs2AgBiBr6 single crystals with different contact electrodes (Au, Ag, and Al). It is found that a good Ohmic contact with Ag electrodes enables excellent photo-response behaviors. Furthermore, we studied the photodetectors based on Cs2AgBiBr6 single crystals using Ag electrodes under room and low temperature conditions, which underwent phase transition. Cs2AgBiBr6 single crystal photodetectors show clear differences at room and low temperatures, which is caused by the work function changes of Cs2AgBiBr6 single crystals induced by the reversible phase transition. These attractive properties may enable opportunities to apply emerging double perovskite single-crystalline materials for high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

The development of scalable deposition methods for stable perovskite layers is a prerequisite for the development and future commercialization of perovskite solar modules. However, there are two major challenges, i.e., scalability and stability. In sharp contrast to a previous report, here we develop a fully vapor based scalable hybrid chemical vapor deposition (HCVD) process for depositing Cs-formamidinium (FA) mixed cation perovskite films, which alleviates the problem encountered when using conventional solution coating of mainly methylammonium lead iodide (MAPbI3). Using our HCVD method, we fabricate perovskite films of Cs0.1FA0.9PbI2.9Br0.1 with enhanced thermal and phase stabilities, by the intimate incorporation of Cs into FA based perovskite films. In addition, the SnO2 electron transport layer (ETL) (prepared by sputter deposition) is found to be damaged during the HCVD process. In combination with precise interface engineering of the SnO2 ETL, we demonstrate relatively large area solar modules with efficiency approaching 10% and with a designated area of 91.8 cm2 fabricated on 10 cm × 10 cm substrates (14 cells in series). On the basis of our preliminary operational stability tests on encapsulated perovskite solar modules, we extrapolated that the T80 lifetime is approximately 500 h (under the light illumination of 1 sun and 25 °C). [ABSTRACT FROM AUTHOR]

The corrected text is below, For ligand modification, 0.5 mg pentaerythritol tetrakis(3-mercaptopropionate) (ML) is dissolved in 1 mL CB and spun on top of perovskite, These errors do not affect the conclusions of the report. In the supporting information file of the same manuscript, on Page 2, in the "Device fabrication" an error related to the protocol for ligand modification was made. [Extracted from the article]

[Display omitted] • DBD plasma coupled with oxygen accelerated the degradation of chlorinated aromatic compounds (CACs) in water. • O 3 , ·OH, ·O 2 – and 1O 2 were the dominant reactive oxygen species. • High mineralization efficiency of CACs was achieved in DBD/O 2 process. • The intermediates of CACs degradation were consistent with the theoretical calculation. • Completed degradation was also achieved in the CACs contaminated soils. Chlorinated aromatic compounds (CACs), a kind of refractory pollutants, pose a potential risk to the environment and human health. Herein, dielectric barrier discharge (DBD) plasma is employed to enhance the degradation of 2,4-dichlorophenol (2,4-DCP) from water, and O 2 is the most efficient working atmosphere with totally 2,4-DCP degradation in 40 min. O 3 , ·OH, ·O 2 – and 1O 2 are the main active species responsible for the degradation, while the contribution of hydrated electrons and reactive nitrogen species is almost negligible. Moreover, highly efficient o-Nitrochlorobenzene (o-NCB) and chlorobenzene (CB) degradation and mineralization are also achieved in DBD/O 2 process. All the CACs are completely degraded in 60 min following the degradation rate order of CB > 2,4-DCP > o-NCB, which almost follows the order of ionization potential values. The mineralization efficiencies of CB, 2,4-DCP and o-NCB reach 61.14 %, 70.50 % and 92.77 % in DBD/O 2 process, respectively, which are 1.74,1.15 and 1.28 times higher than that in DBD process alone. Based on theoretical calculation and intermediates analysis, three common degradation pathways are proposed including hydroxylation, dechlorination and ring-opening. Soil remediation experiments further indicate the high efficiency and promising perspective of DBD/O 2 process in CACs contaminated soil treatment. This work is instructive to elucidate the importance of O 2 atmosphere in the degradation of CACs by DBD plasma system and provides an alternative way for removing CACs from water and soil. [ABSTRACT FROM AUTHOR]

Inorganic-organic hybrid lead halide perovskites are emerging optoelectronic materials for solar cell application. However, the toxicity concerns and poor stability largely hamper their practical applications. For these reasons, the search for "perovskite-inspired" alternatives, having the same advantages but overcoming the drawbacks of the lead-based one, has become an important sector in the field. Among the candidates, Bi3+ and Sb3+ containing materials are of great interest, due to their electronic structures resembling the Pb2+. Bismuth/antimony chalcohalides have been known for a long time as the potential absorber in photovoltaics, even if their performances are still low. Interestingly, pnictogen chalcohalides can be the stepping stone toward numerous quaternary compounds, including some perovskite structures. The understanding of the fundamental properties and the current limitations of both the starting ternary compounds and the final quaternary materials can allow the achievement of improved photovoltaic absorbers, stable, and efficient. In this review, the fundamental properties and device performances of many ternary pnictogen chalcohalides and the derived quaternary compounds are summarized, focusing on the different preparation strategies. [ABSTRACT FROM AUTHOR]

Organic-inorganic perovskite solar cells have been highlighted as one of the most competitive thin film photovoltaics recently. It is promising to further raise the power conversion efficiency if high quality absorber is coupled with rational optical design for effective photon management. Here we demonstrate the implementation of perovskite nanostructure assembly by simple solution process to interfere the propagation of light inside the adjacent absorber. It enhances light harvesting to obtain higher attainable photocurrents and photovoltage in the resultant devices, achieving a decent power conversion efficiency (PCE) over 19% consequently. The presented nanostructure assembly integrates perovskite materials with desirable processibility and chemical compatibility by chemical synthesis and interface modification. For the first time, a synergetic localized “gratings” and enhanced fluorescence effect was demonstrated to govern photon management in perovskite solar cells. These findings may serve as a general guide to design and construct perovskite thin solar cells with efficiency approaching Shockley-Queisser limit. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskites with mixed organic cations and/or halides have attracted increasing attention due to their superior optoelectronic properties, which are tailorable for different applications. To obtain a deeper understanding of materials properties, single crystals are regarded as the best platform among various building blocks for fundamental study. Here, we synthesized a series of perovskite single crystals with mixed organic cations (APbI3, A = CH3NH3+, MA+; or CH(NH2)2+, FA+) along the compositional space, and conducted a systematic investigation to correlate the carrier behavior with the organic cations. The single crystals were synthesized via inverse temperature crystallization assisted by hydroiodic acid, where the quality of the crystals could be judiciously controlled by the thermodynamic process. It is found that the substitution of 15% MA+ in FAPbI3 single crystals stabilizes the phase with the best charge transport characteristics. Both photodetector and J–V measurements suggested that FA0.85MA0.15PbI3 single crystal exhibits suppressed ion migration compared with the counterpart FA0.15MA0.85PbI3 single crystal. These results represent an important step to highlight the role of organic cations in hybrid perovskite materials, which will further benefit fundamental understanding of materials and device optimization. [ABSTRACT FROM AUTHOR]

Residual lattice strain in halide perovskites has been recognized as a key factor that affects device efficiency and stability of perovskite solar cells (PSCs). Here, we reveal that the escape of organic ammonium halide and their inhomogeneous distribution after thermal annealing could cause severe residual strain in intrinsic thermal stable formamidinium-cesium (FACs) perovskite films. Thus, we develop an imprint-assisted organic ammonium halide compensation strategy for residual lattice strain relaxation. We demonstrate the residual lattice strain is well-released after post-treatment, along with further perovskite grain growth/coalescence, crystallinity improvement, and defect repair. As a result, the strain-free PSCs with nickel oxide based inverted architecture exhibit a power conversion efficiency as high as 21.30% and the corresponding encapsulated devices retain 98% of their initial efficiencies at 45 °C under 1-sun equivalent white-light light-emitting diode array illumination with maximum power point tracking in the ambient environment for 1000 h. [Display omitted] • The compressive strain of perovskite film results from FA+ componential gradient during the annealed process. • Extra FA+ compensation with flat imprint assisted can relax compressive strain in perovskite film. • PCEs up to 21.30% are achieved for nickel oxide-based FACs inverted perovskite solar cells. [ABSTRACT FROM AUTHOR]

Three 9,9-dihexyl-9H-fluorene (DHF) functionalized zinc porphyrin dyes (coded as ZZX-N3, ZZX-N4, and ZZX-N5) were designed and synthesized for dye-sensitized solar cells. Then, DHF and benzoic acid were conjugated to the porphyrin ring through triple bonds to act as a spacer to elongate the π-conjugation and as an acceptor for an efficient electron injection, respectively. A bis(9,9-dihexyl-9H-fluorene-7-yl)-amine (BFA) and a bis(4-hexylphenyl)amine (BPA) were further linked to DHF to act as electron donors in ZZX-N3 and ZZX-N4, respectively. ZZX-N5 did not have any electron donor and served as a reference. Moreover, ZZX-N3- and ZZX-N4-sensitized cells exhibited broader sunlight absorption than ZZX-N5, and as a result, higher photon-to-electricity efficiency (PCE) (ZZX-N3, 3.83%; ZZX-N4, 4.2%; ZZX-N5, 3.70%) was observed. The results are consistent with well-separated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) in ZZX-N3 and ZZX-N4 than in ZZX-N5. However, the overall conversion efficiency of ZZX-N3- and ZZX-N4-sensitized cells was low, which is due to significant dye aggregation induced by the extra long alkyl-chains on the donor groups. This was evidenced by blue and red shifts of the absorption spectra of dye-coated TiO2 films. In addition, the extra long-chains also did not offer better shielding to prevent electron recombination of injected electrons with I3- in electrolyte as revealed by electrochemical impedance spectroscopy. When a co-sensitizer (coded as PBS) was used, a new peak corresponding to the absorption of PBS at 560 nm was observed on the incident photon to charge carrier efficiency (IPCE) spectra; however, the overall photovoltaic performance was not improved due to the significant decrease of dye-loading density of porphyrin dyes, indicating a need to break off the trade-off between dye-loading and light-harvesting. [ABSTRACT FROM AUTHOR]

Inverted perovskite solar cells (PSCs) based on formamidinium-cesium (FACs) perovskites with nickel oxide as hole transport layer (HTL) have attracted much attention due to their good stability. However, their open-circuit voltage (V OC) and efficiencies lag far behind those of inverted PSCs based on organic HTLs. Here, we introduce an organic dye coumarin 343 (C343) as a molecular additive into the perovskite to reduce V OC loss and improve the efficiency of nickel oxide-based inverted PSCs. We demonstrate that the strong coordination between the carboxyl groups in C343 and under-coordinated Pb2+ not only optimizes perovskite crystal growth during perovskite formation, but also reduces the defects densities within perovskite films. As a result, our C343 doped PSCs achieve an optimal efficiency of 20.9% (certified 20.2%), which is one of the highest efficiencies for FACs perovskite and nickel oxide based inverted PSCs reported so far. Moreover, the utilization of C343 also benefits devices' stability, making the devices maintain over 94% and 95% of the initial PCE after aging at 85 °C for 500 h in N 2 glovebox and operation under continuous 1 sun illumination with the maximum power point (MPP) tracking at the temperature around 65 °C in ambient air for 500 h, respectively. [Display omitted] • Coumarin 343 can optimize perovskite crystal growth and passivate defects by its coordination with uncoordinated Pb2+ ions. • Coumarin 343 is demonstrated to improve the thermal stability and operational stability of the devices. • PCEs up to 20.94% (certified 20.2%) are achieved for nickel oxide-based formamidinium-cesium perovskite solar cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • VUV/UV/persulfate (VUV/UV/PS) process obviously promoted BPA degradation. • Interactions of selected variables on BPA degradation efficiency were significant. • Sulfate radicals were proved to be the dominant reaction active species. • BPA degradation was caused by hydroxylation reaction and β -scission of C–C bond. • The VUV/UV/PS process for BPA degradation was more energy-saving. Enhanced degradation and mineralization of bisphenol A (BPA) known as a typical endocrine disrupting chemical (EDC) in VUV/UV-activated persulfate process (VUV/UV/PS) were investigated. The pseudo-first-order reaction rate constant and total organic carbon (TOC) removal ratio of BPA in this process were 1.75 and 1.70 times of those in UV-activated PS process (UV/PS), respectively. The excitation-emission matrix (EEM) fluorescence spectroscopy of reaction solution at different time clearly indicated the change of BPA and its intermediates during the reaction process. The significant interactive effects of three important operating parameters including the initial concentration of BPA, the initial concentration of PS and the initial pH of solution on BPA degradation efficiency were evaluated and optimized by using central composite design (CCD) of response surface methodology (RSM). At the optimum experimental conditions (i.e., 30 mg/L BPA, 1.25 mM PS and at pH 9), the maximum degradation efficiency of BPA at 2 min was up to 92.2%. Sulfate radicals (SO 4 •-) were the dominant reaction activate species for BPA degradation. Based on the analysis of liquid chromatograph-mass spectrometry (LC/MS), gas chromatograph-mass spectrometry (GC/MS) and Fourier transform infrared spectroscopy (FTIR) of the reaction mixture and density function theory (DFT) calculation, it was proposed that BPA degradation was mainly caused by SO 4 •--induced hydroxylation reaction, HO• addition and β-scission of C–C bond. Moreover, the electrical energy consumption of BPA degradation in VUV/UV/PS process was less. Additionally, BPA in real water samples could also be effectively degraded at lower treatment costs in this process. Hence, the present study demonstrates that VUV/UV activation of PS is a highly efficient and economical alternative to remove BPA in real water matrices.. [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]