Crystallization Regulation and Morphological Evolution for HTM-free Tin-Lead (1.28eV) Alloyed Perovskite Solar Cells

There have been huge achievements of all-perovskite tandem solar cells,which recently realized the highest power conversion efficiency of 24.8%.However,the complex device structure and complicated manufacture processes severely restrict the further development of all-perovskite tandem solar cells.In this work,we successfully fabricated high-efficiency hole transport material-free(HTM-free)Sn−Pb alloyed narrow bandgap perovskite solar cells(PSCs)by introducing guanidinium thiocyanate(GASCN)and hydroiodic acid(HI)into the perovskite precursor solution.GASCN and HI play a positive synergy effect during perovskite crystallization process resulting in larger grain size,fewer surface defects,and lower trap density to suppress the Sn^(2+)oxidation degradation.Furthermore,they could effectively adjust the energy level of perovskite materials,reduce the energy level difference between perovskite and ITO resulting in more efficiently transport of free hole charge carriers.As a result,with adding GASCN and HI,the achieved highest power conversion efficiency of HTM-free devices increased from 12.58%to 17.85%,which is one of the highest PCEs among all values reported to date for the HTM-free narrow-bandgap(1.2-1.4 eV)Sn−Pb binary PSCs.Moreover,the optimized device shows improved environmental stability.Our additive strategy manifests a remarkable step towards the facile,cost-efficient fabrication of HTM-free perovskite-based tandem solar cells with both high efficiency and simple fabrication process.

Crystallization and Orientation Modulation Enable Highly Efficient Doctor-Bladed Perovskite Solar Cells

With the rapid rise in perovskite solar cells(PSCs)performance,it is imperative to develop scalable fabrication techniques to accelerate potential commercialization.However,the power conversion efficiencies(PCEs)of PSCs fabricated via scalable two-step sequential deposition lag far behind the state-of-the-art spin-coated ones.Herein,the additive methylammonium chloride(MACl)is introduced to modulate the crystallization and orientation of a two-step sequential doctorbladed perovskite film in ambient conditions.MACl can significantly improve perovskite film quality and increase grain size and crystallinity,thus decreasing trap density and suppressing nonradiative recombination.Meanwhile,MACl also promotes the preferred face-up orientation of the(100)plane of perovskite film,which is more conducive to the transport and collection of carriers,thereby significantly improving the fill factor.As a result,a champion PCE of 23.14%and excellent longterm stability are achieved for PSCs based on the structure of ITO/SnO_(2)/FA_(1-x)MA_xPb(I_(1-y)Br_y)_3/Spiro-OMeTAD/Ag.The superior PCEs of 21.20%and 17.54%are achieved for 1.03 cm~2 PSC and 10.93 cm~2 mini-module,respectively.These results represent substantial progress in large-scale two-step sequential deposition of high-performance PSCs for practical applications.

Synthesis,Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-（3-amino-[1,2,4]triazol-1-yl）-3,3-dimethyl-butan-2-one（3） was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one（1） and ~1H-[1,2,4]triazol-3-ylamine（2） with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227（8）, b = 27.924（4）, c = 6.2282（7） ？, β = 101.892（11）°, V = 973.9（2） ？~3, Z = 4, T = 180.00（10） K, μ（MoKα） = 0.087 mm^（-1）, Dc = 1.243 g/cm^3, 3832 reflections measured（3.648≤θ≤26.022°）, 1916 unique reflections（Rint = 0.0359, Rsigma = 0.0572） used in all calculations. The final R = 0.0557（I 〉 2σ（I）） and w R = 0.1276（all data）. Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L（50 ppm） in soybeen（He Feng-50）. Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.

Structural insight into mechanisms for dynamic regulation of PKM2

Pyruvate kinase isoform M2 （PKM2） converts phospho- enolpyruvate （PEP） to pyruvate and plays an important role in cancer metabolism. Here, we show that post- translational modifications and a patient-derived muta- tion regulate pyruvate kinase activity of PKM2 through modulating the conformation of the PKM2 tetramer. We determined crystal structures of human PKM2 mutants and proposed a ＂seesaw＂ model to illustrate confor- mational changes between an inactive T-state and an active R-state tetramers of PKM2. Biochemical and structural analyses demonstrate that PKM2^Y105E （phos- phorylation mimic of Y105） decreases pyruvate kinase activity by inhibiting FBP （fructose 1,6-bisphosphate）- induced R-state formation, and PKM2K^3305Q （acetylation mimic of K305） abolishes the activity by hindering tet- ramer formation. K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions. Our study reveals the mechanism for dynamic regulation of PKM2 by post- translational modifications and a patient-derived muta- tion and provides a structural basis for further investi- gation of other modifications and mutations of PKM2 yet to be discovered.

Recent progress on garnet phosphor ceramics for high power solid-state lighting

As the fourth-generation light source,solid-state lighting has developed rapidly in the past 30 years due to its advantages of high efficiency and environmental protection.It is widely used in various scenes such as automobile headlights,projection displays,industrial production,and remote lighting.High-power,high-brightness white light-emitting diodes(LEDs)and laser diodes(LDs)technology put forward new requirements for the service stability of color conversion materials.Garnet phosphor ceramics have emerged with their unique advantages of withstanding high power excitation density and the flexibly tunable spectrum.In this article,the research progress of garnet based phosphor ceramics for high-power solid-state lighting was comprehensively reviewed.Firstly,the band gap and coordination environment regulations of luminescence centers of garnet phosphor were summarized.Secondly,the improvement of luminous efficacy via defects regulation was discussed.Thirdly,the relationship between the geometric design and the lighting performance was elucidated.Fourthly,the characterization methods of phosphor ceramics for laser lighting were introduced and illustrated.Finally,the development trend of garnet phosphor ceramics in solid state lighting and display was prospected.

Synthesis and Characterization of TS-1 with Aid of Supercritical CO2

A new route to synthesize TS-1 has been developed using the supercritical carbon dioxide（SCCO2） as a crystallization-assistant agent. SCCO2 plays a dual role： as a reagent changing the alkalinity during the crystallization process and as a medium eliminating mass-transfer limitations（both within the bulk fluid and through liquid/gas, solid/gas or solid/liquid phase boundaries）. In this route, it was shown that the Ti content in TS-I increase compared with that in the TS-1 prepared without SCCO2, but decrease while the SCCO2 pressure increase. The prepared crystal morphology also underwent significant change. The crystallization time of TS-1 can be shorten a lot.