Accelerated Sequential Deposition Reaction via Crystal Orientation Engineering for Low-Temperature,High-Efficiency Carbon-Electrode CsPbBr_(3) Solar Cells

Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)films.Such a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)phase.Theoretical calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)planes.Therefore,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation stability.Meanwhile,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.

A review of the most recent progresses of state-of-art gallium oxide power devices

Until very recently, gallium oxide(Ga_2O_3) has aroused more and more interests in the area of power electronics due to its ultra-wide bandgap of 4.5–4.8 eV, estimated critical field of 8 MV/cm and decent intrinsic electron mobility limit of250 cm2/(V·s), yielding a high Baliga's figures-of-merit(FOM) of more than 3000, which is several times higher than GaN and SiC.In addition to its excellent material properties, potential low-cost and large size substrate through melt-grown methodology also endows β-Ga_2O_3 more potential for future low-cost power devices. This article focuses on reviewing the most recent advances ofβ-Ga_2O_3 based power devices. It will be starting with a brief introduction to the material properties of β-Ga_2O_3 and then the growth techniques of its native substrate, followed by the thin film epitaxial growth. The performance of state-of-art β-Ga_2O_3 devices, including diodes and FETs are fully discussed and compared. Finally, potential solutions to the challenges of β-Ga_2O_3 are also discussed and explored.

Interfacial Voids Trigger Carbon-Based, All-Inorganic Cs Pb IBr2 Perovskite Solar Cells with Photovoltage Exceeding 1.33 V

A novel interface design is proposed for carbon-based,all-inorganic CsPbIBr2 perovskite solar cells(PSCs)by introducing interfacial voids between TiO2 electron transport layer and CsPbIBr2 absorber.Compared with the general interfacial engineering strategies,this design exempts any extra modification layer in final PSC.More importantly,the interfacial voids produced by thermal decomposition of 2-phenylethylammonium iodide trigger three beneficial e ects.First,they promote the light scattering in CsPbIBr2 film and thereby boost absorption ability of the resulting CsPbIBr2 PSCs.Second,they suppress recombination of charge carriers and thus reduce dark saturation current density(J0)of the PSCs.Third,interfacial voids enlarge built-in potential(Vbi)of the PSCs,awarding increased driving force for dissociating photo-generated charge carriers.Consequently,the PSC yields the optimized e ciency of 10.20%coupled with an open-circuit voltage(Voc)of 1.338 V.The Voc achieved herein represents the best value among CsPbIBr2 PSCs reported earlier.Meanwhile,the non-encapsulated PSCs exhibit an excellent stability against light,thermal,and humidity stresses,since it remains^97%or^94%of its initial e ciency after being heated at 85℃for 12 h or stored in ambient atmosphere with relative humidity of 30–40%for 60 days,respectively.

Human iPS Cells Loaded with MnO2-Based Nanoprobes for Photodynamic and Simultaneous Enhanced Immunotherapy Against Cancer

How to trigger strong anti-tumor immune responses has become a focus for tumor therapy.Here,we report the human-induced pluripotent stem cells(iPSs)to deliver MnO2@Ce6 nanoprobes into tumors for simultaneous photodynamic therapy(PDT)and enhanced immunotherapy.Ce6 photosensitizer was attached on manganese dioxide(MnO2)nanoparticles,and resultant MnO2@Ce6 nanoprobes were delivered into mitomycin-treated iPSs to form iPS-MnO2@Ce6 nanoprobes.The iPS-MnO2@Ce6 actively targeted in vivo tumors,the acidic microenvironment triggered interaction between MnO2 and H2O2,released large quantities of oxygen,alleviated hypoxia in tumor.Upon PDT,singlet oxygen formed,broken iPSs released tumor-shared antigens,which evoked an intensive innate and adaptive immune response against the tumor,improving dendritic cells matured,effector T cells,and natural killer cells were activated.Meanwhile,regulatory T cells were reduced,and then the immune response induced by iPS-MnO2@Ce6 was markedly stronger than the immune reaction induced by MnO2@Ce6(P<0.05).The iPS-MnO2@Ce6 markedly inhibited tumor growth and metastasis and reduced mortality in mice models with tumor.Human iPS s loaded with MnO2-based nanoprobes are a promising strategy for simultaneous PDT and enhanced immunotherapy against tumor and own clinical translational prospect.

Electrical performance and reliability analysis of vertical gallium nitride Schottky barrier diodes with dual-ion implanted edge termination

In this study,a galliumnitride(GaN)substrate and its 15μmepitaxial layer were entirely grown by adopting the hydride vapor phase epitaxy(HVPE)technique.To enhance the breakdown voltage(VBR)of vertical GaN-on-GaN Schottky barrier diodes(SBDs),a dual ion coimplantation of carbon and heliumwas employed to create the edge termination.The resulting devices exhibited a low turn-on voltage of 0.55 V,a high Ion/Ioff ratio of approximately 109,and a lowspecific onresistance of 1.93 mU cm^(2).When the ion implantation edge was terminated,the maximumVBR of the devices reached 1575 V,with an average improvement of 126%.These devices demonstrated a high figure of merit(FOM)of 1.28 GW cm^(-2) and showed excellent reliability during pulse stress testing.

Graded Heterojunction Improves Wide-Bandgap Perovskite for Highly Efficient 4-Terminal Perovskite/Silicon Tandem Solar Cells

Wide-bandgap(WBG)perovskite solar cells(PSCs)are essential for highly efficient and stable silicon/perovskite tandem solar cells.In this study,we adopted a synthetic strategy with lead thiocyanate(Pb(SCN)_(2))additive and methylammonium chloride(MACl)posttreatment to enhance the crystallinity and improve the interface of WBG perovskite films with a bandgap of 1.68 eV.The excessive PbI_(2)was formed at grain boundaries and converted into MAPbI_(3-x)Cl_(x)perovskites,which are utilized to form the graded heterojunction(GHJ)and compressive strain.This is beneficial for passivating nonradiative recombination defects,suppressing halide phase segregation,and facilitating carrier extraction.Subsequently,the device with GHJ delivered a champion efficiency of 20.30%and superior stability in ambient air and under 85℃.Finally,we achieved a recorded efficiency of 30.91%for 4-terminal WBG perovskite/TOPCon tandem silicon solar cells.Our findings demonstrate a promising approach for fabricating efficient and stable WBG PSCs through the formation of GHJ.

Ultrahigh fill-factor all-inorganic CsPbBr_(3)perovskite solar cells processed from two-step solution method and solvent additive strategy

All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)have attracted more attentions due to the excellent environmental stability,however,the wide bandgap and relatively poor crystallinity of CsPbBr_(3)have been the main obstacle to improve their power conversion efficiency(PCE).Herein,we proposed an efficient and simple strategy of precursor additive in the two-step aqueous-solution method,the resulted CsPbBr_(3)film has achieved more uniform grain size,almost pure perovskite phase,smoother surface,less defects,enhanced light absorption and longer carrier lifetime.This is due to the rapid evaporation of additive(IPA and CH_(3)OH)in the CsBr/H_(2)O precursor leads to a relatively higher local CsBr concentration on the surface of PbBr_(2),which can provide more nucleation sites and accelerate the crystallization of perovskite.Further,when utilizing the optimal additive of 5%(in volume)IPA,the HTM-free carbonbased CsPbBr_(3)PSCs obtained a PCE improvement from 9.09%to 10.29%,and an ultrahigh fill factor(FF)of 85.21%.What is more,by adding 0.1 mol/L PbCl_(2)into the PbBr_(2)solution in the first step,the open circuit voltage of device has increased from 1.36 V to 1.48 V,the champion PCE reached 10.37%(steady output PCE of 10.17%),and the non-encapsulated device could maintain 85%of its initial efficiency after 50 d in the air.This work provides a cost-effective approach to grow CsPbBr_(3)film and boosts the efficiency benchmark of the CsPbBr_(3)PSCs to more than 10%,it is desirable that the highly efficient and stable CsPbBr_(3)PSCs can be developed in future.

Wide-range-adjusted threshold voltages for E-mode AlGaN/GaN HEMT with a p-SnO cap gate

p-GaN cap layer has been recognized as a commercial technology to manufacture enhanced-mode(E-mode)AlGaN/GaN high electron mobility transistor(HEMT);however,the difficult activation of Mg doping and etching damage of p-GaN limit the further improvement of device performance.Thus,the more cost-effective cap layer has attracted wide attention in GaN-based HEMT.In this paper,p-type tin monoxide(p-SnO)was firstly investigated as a gate cap to realize E-mode AlGaN/GaN HEMT by both Silvaco simulation and experiment.Simulation results show that by simply adjusting the thickness(50 to 200 nm)or the doping concentration(3×10^(17)to 3×10^(18)cm^(-3))of p-SnO,the threshold voltage(V_(th))of HEMT can be continuously adjusted in the range from zero to 10 V.Simultaneously,the device demonstrated a drain current density above 120 mA mm^(-1),a gate breakdown voltage(V_(BG))of 7.5 V and a device breakdown voltage(V_(B))of 2470 V.What is more,the etching-free AlGaN/GaN HEMT with sputtered p-SnO gate cap were fabricated,and achieved a positive V_(th) of 1 V,V_(BG) of 4.2 V and V_(B) of 420 V,which confirms the application potential of the p-SnO film as a gate cap layer for E-mode GaN-based HEMT.This work is instructive to the design and manufacture of p-oxide gate cap E-mode AlGaN/GaN HEMT with low cost.

Dual‑Performance Optimized Silks from Ultra‑Low Dose Polymer Dots Feeding and Its Absorption, Distribution and Excretion in the Silkworms

Fluorescent polymer dots(Pdots)have the advantages of excellent optical properties,great biocompatibility and high photostability.Herein,we feed ultra-low doses Pdots to silkworms for the first time and aim to prepare dual-performance modified silks.After Pdots feeding,the fluorescence signal of cocoons and degummed silks increases significantly,which is more stable and more uniform than that of post-treatment silks.Moreover,Pdots hinder the conformation transformation of silk fibroin and improve the mechanical property of twisted silk strand.The highest elongation at break point is 20.75±0.03% and breaking strength is 271.7±3.8 MPa.With excellent fluorescence and mechanical properties,the optimized silks are successfully applied as a scaffold for cell culture and imaging.Furthermore,we investigate the metabolism of Pdots in the silkworms for understanding the behaviours of Pdots in the process of silks synthesis and secretion.

Slow halide exchange in CsPbIBr_(2) films for high-efficiency,carbon-based,all-inorganic perovskite solar cells

Halide exchange offers a versatile way to modify the properties of halide perovskites,but it is particularly challenging to slow the reaction rate to restrain defect growth in the products.Herein,we propose a slow halide exchange strategy to simultaneously fine-tune the optical and microstructural characteristics of CsPbIBr_(2) films by physically pairing CsPbIBr_(2) and CH_(3)NH_(3)PbI_(3) films.Once a proper heating treatment is applied,halide exchange of Br^(-)and I^(-)ions between the films is activated,and the reaction rate can be well-controlled by the heating recipe,in which a high temperature can accelerate the exchange reaction,while a low temperature slows or stops it.By using an optimal halide exchange temperature(110℃)and time(2 h),the parent CsPbIBr_(2) film was transformed into high-quality CsPbI_(1+x)Br_(2-x) film,featuring an extended absorption onset from 590 to 625 nm,coarsened grains,improved crystallinity,reduced surface roughness,suppressed halide phase segregation,and identical stability to the pristine film.Accordingly,the efficiency of a carbon-based,all-inorganic perovskite solar cell(PSC)was boosted to 10.94%,which was much higher than that of the pristine CsPbIBr_(2) film(8.21%).The CsPbI_(1+x)Br_(2-x) PSC also possessed excellent tolerance against heat and moisture stresses.

Research on the hydrogen terminated single crystal diamond MOSFET with MoO_3 dielectric and gold gate metal

The single crystal diamond with maximum width about 10 mm has been grown by using microwave plasma chemical vapor deposition equipment. The quality of the grown diamond was characterized using an X-ray diffractometer. The FWHM of the（004） rocking curve is 37.91 arcsec, which is comparable to the result of the electronic grade single crystal diamond commercially obtained from Element Six Ltd. The hydrogen terminated diamond field effect transistors with Au/Mo03 gates were fabricated based on our CVD diamond and the characteristics of the device were compared with the prototype Al/MoO3 gate. The device with the Au/MoO3 gate shows lower on-resistance and higher gate leakage current. The detailed analysis indicates the presence of aluminum oxide at the Al/MoO3 interface, which has been directly demonstrated by characterizing the interface between A1 and MoO3 by X-ray photoelectron spectroscopy. In addition, there should be a surface transfer doping effect of the MoO3 layer on H-diamond even with the atmospheric-adsorbate induced 2 DHG preserved after MoO3 deposition.