Besides widely used surface passivation, engineering the film crystallization is an important and more fundamental route to improve the performance of all-inorganic perovskite solar cells.H erein, we have developed au rea-ammonium thiocyanate (UAT)m olten salt modification strategy to fully release and exploit coordination activities of SCN À to deposit high-quality CsPbI 3 film for efficient and stable all-inorganic solar cells.T he UATi sd erived by the hydrogen bond interactions between urea and NH 4 + from NH 4 SCN.W itht he UAT, the crystal quality of the CsPbI 3 film has been significantly improved and al ong single-exponential charge recombination lifetime of over 30 ns has been achieved. With these benefits,t he cell efficiency has been promoted to over 20 %( steady-state efficiency of 19.2 %) with excellent operational stability over 1000 h. These results demonstrate apromising development route of the CsPbI 3 related photoelectric devices.

Water in the hydrophobic cavity of human interleukin 1␤, which was detected by NMR spectroscopy but was invisible by high resolution x-ray crystallography, has been mapped quantitatively by measurement and phasing of all of the low resolution x-ray diffraction data from a single crystal. Phases for the low resolution data were refined by iterative density modification of an initial f lat solvent model outside the envelope of the atomic model. The refinement was restrained by the condition that the map of the difference between the electron density distribution in the full unit cell and that of the atomic model be f lat within the envelope of the well ordered protein structure. Care was taken to avoid overfitting the diffraction data by maintaining phases for the high resolution data from the atomic model and by a resolution-dependent damping of the structure factor differences between data and model. The cavity region in the protein could accommodate up to four water molecules. The refined solvent difference map indicates that there are about two water molecules in the cavity region. This map is compatible with an atomic model of the water distribution refined by using XPLOR. About 70% of the time, there appears to be a water dimer in the central hydrophobic cavity, which is connected to the outside by two constricted channels occupied by single water molecules Ϸ40% of the time on one side and Ϸ10% on the other.Analysis of NMR data from solutions of human interleukin-1␤ (hIL-1␤) has indicated that the hydrophobic cavity in the center of the protein contains positionally disordered water (1). However, this water has escaped detection by four independent high resolution (Ϸ2 Å) crystallographic studies (2-5). On the basis that no water molecules were observed crystallographically in this or similar hydrophobic protein cavities, Matthews et al. (6) have questioned the interpretation of the observed nuclear Overhauser enhancement cross peaks attributed to water molecules that are within Ϸ5 Å of protons of the cavity-forming aliphatic residues.Because the existence of positionally disordered water in hydrophobic protein cavities has been controversial (and because such mobile water can be crucially involved in protein dynamics), we have critically assessed the information available from x-ray crystallography regarding the distribution of disordered solvent in an hIL-1␤ crystal. Refinement of the phases for all of the low resolution data, from 55-to 4.5-Å spacing, restrained by the information about the well ordered protein structure from the high resolution (2.3 Å) data, demonstrates that crystallographically elusive solvent, which is detectable by NMR, can be visualized quantitatively in a difference electron density map. The solvent density distribution is mapped from the difference between the average structure of the whole crystal, calculated from the completely phased data, and that of the atomic model of the ordered protein structure, refined from the high resolution data.Atomic coordinates, occupancies...

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All-inorganic perovskite cesium lead iodide (CsPbI 3 ) exhibits excellent prospects for commercial application as a light absorber in single-junction or tandem solar cells due to its outstanding thermal stability and proper bandgap. However, the device performance of CsPbI 3 -based perovskite solar cells (PSCs) is still restricted by the unsatisfactory crystal quality and severe non-radiative recombination. Herein, inorganic additive ammonium halides are introduced into the precursor solution to regulate the nucleation and crystallization of the CsPbI 3 film by exploiting the atomic interaction between the ammonium group and the Pb-I framework. The grain boundaries and interfacial contact of the CsPbI 3 film have been improved, which leads to significant suppression in the non-radiative recombination and an enhancement in the charge transport ability. With these benefits, a high efficiency of 18.7% together with an extraordinarily high fill factor of 0.83-0.84 has been achieved, comparable to the highest records reported so far. Moreover, the cell exhibits ultra-high photoelectrical stability under continuous light illumination and high bias voltage with 96% of its initial power-conversion efficiency being sustained after 2000 h operation, even superior to the worldchampion CsPbI 3 solar cell. The findings are promising for the development and application of all-inorganic PSCs using a simple inorganic additive strategy.

All‐inorganic CsPbI3 perovskite has emerged as an important photovoltaic material due to its high thermal stability and suitable bandgap for tandem devices. Currently, the cell performance of CsPbI3 solar cells is mainly subject to a large open‐circuit voltage (VOC) deficit. Herein, a multifunctional room‐temperature molten salt, dimethylamine acetate (DMAAc) is demonstrated, which not only directly acts as a solvent for precursor solutions, but also regulates the phase conversion process of the CsPbI3 film for high‐efficiency photovoltaics. DMAAc can stabilize the DMAPbI3 structure and eliminate the Cs4PbI6 intermediate phase, which is easily spatially segregated. Meanwhile, a new homogeneous intermediate phase DMAPb(I,Ac)3 is formed, which finally affords high‐quality CsPbI3 films. With this approach, the charge capture activity of defects in the CsPbI3 film is significantly suppressed. Consequently, a VOC of 1.25 V and >21% power conversion efficiency are achieved, which is the record highest reported thus far. This intermediate phase‐regulation strategy is believed to be applicable to other perovskite material systems.

extensively researched from the material to the device in the past few years; however, the power conversion efficiency (PCE) of CsPbI 3 -based solar cells still lags behind hybrid perovskite solar cells (PSCs) as well as its maximum theoretical PCE. [2] Currently, the application of CsPbI 3 in PSCs is mainly perplexed by unsatisfied CsPbI 3 film quality, including black-phase stability, defects, and crystallinity. [3] Particularly, the black-phase CsPbI 3 is moisture-induced phase instability, that is, the moisture could easily result in phase transition from black phase into unfavorable yellow non-perovskite phase at room temperature. [4] Therefore, a big challenge is stabilizing high-quality black-phase CsPbI 3 films for efficient devices.Generally, the CsPbI 3 black-phase instability is mainly due to its lower tolerance factor, that is, the small size of the Cs + could not sustain PbI 6 octahedra in the cubic α-CsPbI 3 structure, easily leading to the δ-CsPbI 3 transformation. [3,4] To stabilize the black phase of CsPbI 3 films, different methods have been attempted, such as bromide partial iodide substitution to give the CsPbI 2 Br or CsPbIBr 2 , reducing crystal sizes or introducing intermediate phases in some degree. [5] Furthermore, controllable alien element doping into CsPbI 3 films (i.e., Ca 2+ , Sn 2+ , Ge 2+ , Sr 2+ , Mn 2+ , In 3+ , Bi 3+ , etc.) could increase the tolerance factor of the CsPbI 3 in some degree. [6,7] Typically, the replacement of PbI 2 with DMAPbI 3 (HPbI 3 ) as the Pb 2+ resource has directly promoted the PCE to ≈20% along with modifying crystallinity process or introducing surface passivation. [8] Even so, severe non-radiative recombination of the CsPbI 3 is still detrimental to the cell performance and opencircuit voltage (V oc ), in the meantime, the stability of CsPbI 3 perovskite solar cells has not been fully solved yet. [1,9] In addition, unlike hybrid perovskites, post-treatment toward passivating and stabilizing the CsPbI 3 films by in situ introducing low-dimensional perovskites, has not worked well sometimes, especially for the DMAPbI 3 system. [2c,10] Obviously, it is urgent to explore effective strategies to modify CsPbI 3 perovskite crystal growth, passivate defects, and improve the anti-humidity ability of inorganic perovskite solar cells.In current work, Ge element has been firstly incorporated into CsPbI 3 perovskite solar cells based on DMAPbI 3 -based precursor systems. Our investigation reveals that Ge incorporation can modify crystallization growth of CsPb 1−x Ge x I 3 films, Aiming at stable CsPbI 3 perovskite solar cells, Ge incorporated for the first time into DMAPbI 3 -based precursor systems. Ge incorporation is found to be able to modify crystallization growth of CsPb 1−x Ge x I 3 films and reduce annealing temperature and treatment time by lowering CsPbI 3 formation energy. The champion power conversion efficiency (PCE) of 19.52% is achieved with a certified PCE of 18.8%, which is the highest performance of CsPbI 3 PSCs with alien element-dopin...

The photocatalytic reduction of CO2 over Ag/TiO2 composites prepared with a simple silver mirror reaction method was investigated under UV-visible irradiation in both gas-phase (CO2 + water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiO2 nanocomposite exhibits efficient photocatalytic activity due to the surface plasmonic resonance and electron sink effect of the Ag component, which was found to be closely related to the size and loading amount of Ag. The rapid silver method is effective at curbing the size of Ag, so photocatalytic activity can be improved. Diverse organic chemical products were detected, including mainly methane and methanol as well as a small amount of C2 and C3 species such as acetaldehyde and acetone. Possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to the removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly efficient photocatalysts.

Electrical transients enabled by optical excitation and electric detection provide a distinctive opportunity to study the charge transport, recombination and even the hysteresis of a solar cell in a much wider time window ranging from nanoseconds to seconds. However, controversies on how to exploit these investigations to unravel the charge loss mechanism of the cell have been ongoing. Herein, a new methodology of quantifying the charge loss within the bulk absorber or at the interfaces and the defect properties of junction solar cells has been proposed after the conventional tail-state framework is firstly demonstrated to be unreasonable. This methodology has been successfully applied in the study of commercialized silicon and emerging Cu 2 ZnSn(S, Se) 4 and perovskite solar cells herein and should be universal to other photovoltaic device systems with similar structures. Overall, this work provides an alluring route for comprehensive investigation of dynamic physics processes and charge loss mechanism of junction solar cells and possesses potential applications for other optoelectronic devices.