Recent progress of hybrid cathode interface layer for organic solar cells

Organic solar cells(OSCs)have gained conspicuous progress during the past few decades due to the development of materials and upgrading of the device structure.The power conversion efficiency(PCE)of the single-junction device had surpassed 19%.The cathode interface layer(CIL),by optimizing the connection between the active layer and the cathode electrode,has become a momentous part to strengthen the performances of the OSCs.Simultaneously,CIL is also indispensable to illustrating the working mechanism of OSCs and enhancing the stability of the OSCs.In this essay,hybrid CILs in OSCs have been summarized.Firstly,the advancement and operating mechanism of OSCs,and the effects and relevant design rules of CIL are briefly concluded;secondly,the significant influence of CIL on enhancing the stability and PCE of OSCs is presented;thirdly,the characteristics of organic hybrid CIL and organic-inorganic hybrid CIL are introduced.Finally,the conclusion and outlook of CIL are summarized.

Synergistic Optimization of Buried Interface by Multifunctional Organic-Inorganic Complexes for Highly Efficient Planar Perovskite Solar Cells

For the further improvement of the power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs),the buried interface between the perovskite and the electron transport layer is crucial.However,it is challenging to effectively optimize this interface as it is buried beneath the perovskite film.Herein,we have designed and synthesized a series of multifunctional organic-inorganic(OI)complexes as buried interfacial material to promote electron extraction,as well as the crystal growth of the perovskite.The OI complex with BF4−group not only eliminates oxygen vacancies on the SnO_(2) surface but also balances energy level alignment between SnO_(2) and perovskite,providing a favorable environment for charge carrier extraction.Moreover,OI complex with amine(−NH_(2))functional group can regulate the crystallization of the perovskite film via interaction with PbI2,resulting in highly crystallized perovskite film with large grains and low defect density.Consequently,with rational molecular design,the PSCs with optimal OI complex buried interface layer which contains both BF4−and−NH_(2) functional groups yield a champion device efficiency of 23.69%.More importantly,the resulting unencapsulated device performs excellent ambient stability,maintaining over 90%of its initial efficiency after 2000 h storage,and excellent light stability of 91.5%remaining PCE in the maximum power point tracking measurement(under continuous 100 mW cm−2 light illumination in N2 atmosphere)after 500 h.

Interface characteristics and wear resistance of Ni-B_(4)C plated ZTA reinforced high chromium cast iron composite

A chemical composite plating of Ni-B_(4)C was used to prepare the surface-modified zirconia toughened alumina(ZTA)ceramic particles.The ceramic preforms were prepared by the plated ZTA and sodium silicate solution binder,followed by casting infiltration to prepare the ZTA particles reinforced high chromium cast iron(HCCI)composites.The result reveals that a distinct interface layer forms at the ZTA/HCCI interface,which consists of phases of ZrB_(2),FeB,Fe_(2)B,and NaSiO_(4).The interfacial wettability between ZTA and HCCI is improved by the diffusion and reaction of Ni and B_(4)C.The wear test reveals that the Ni-B_(4)C plated ZTA particles can effectively improve the wear resistance of the ZTA/HCCI composite,and the wear rate of the composite is decreased to 11.6%of HCCI.

Improvement in IBC-silicon solar cell performance by insertion of highly doped crystalline layer at heterojunction interfaces

By inserting a thin highly doped crystalline silicon layer between the base region and amorphous silicon layer in an interdigitated back-contact （IBC） silicon solar cell, a new passivation layer is investigated. The passivation layer performance is characterized by numerical simulations. Moreover, the dependence of the output parameters of the solar cell on the additional layer parameters （doping concentration and thickness） is studied. By optimizing the additional passivation layer in terms of doping concentration and thickness, the power conversion efficiency could be improved by a factor of 2.5%, open circuit voltage is increased by 30 mV and the fill factor of the solar cell by 7.4%. The performance enhancement is achieved due to the decrease of recombination rate, a decrease in solar cell resistivity and improvement of field effect passivation at heterojunction interface. The above-mentioned results are compared with reported results of the same conventional interdigitated back-contact silicon solar cell structure. Furthermore, the effect of a-Si：H/c-Si interface defect density on IBC silicon solar cell parameters with a new passivation layer is studied. The additional passivation layer also reduces the sensitivity of output parameter of solar cell to interface defect density.

Robust interface layers with redox shuttle reactions suppress the dendrite growth for stable solid-state Li metal batteries

Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electrolyte during cycles. In this work, we construct a robust functional interface layer on the modified LiB electrode which considerably improves the electrochemical stability of lithium metal electrode in solid state batteries. It is found that the functional interface layer consisting of polydioxolane, polyiodide ion and Li TFSI effectively restrains the growth of lithium dendrites through the redox shuttle reaction of I-/I3-and maintains a good contact between lithium anode and solid electrolyte during cycles. Benefit from these two advantages, the modified Li-B anode exhibits a remarkable cyclic performance in comparison with those of the bare Li-B anode.

Unravelling the essential difference between TiO_(x) and AlO_(x) interface layers on Ta_(3)N_(5) photoanode for photoelectrochemical water oxidation

Tantalum nitride(Ta_(3)N_(5))is a very promising photoanode material due to its narrow band gap(2.1 eV)and suitable band alignment for solar water splitting.However,it suffers from severe photocorrosion during water oxidation.In this work,it was found that surface passivation by AlO_(x) and TiO_(x) layers results in dramatically different PEC performance of Ta_(3)N_(5) photoanode for water oxidation.The mechanism study indicates that the negative charges on AlO_(x) can generate additional field to promote separation of photogenerated charges,while the positive charges on TiO_(x) layer show the opposite effect.As a result,the Ta_(3)N_(5) based photoanode modified with AlO_(x) layer gives a high photocurrent of 12.5 mA cm^(-2) for 24 h at 1.23 V versus the reversible hydrogen electrode(RHE).Dynamic analysis implies that the hole extraction and transfer are significantly improved by the modification with the AlO_(x) layer.This work reveals the importance of the charges on surface passivation layer in interface engineering of photoelectrodes.

SHEAR BEAM MODEL FOR INTERFACE FAILURE UNDER ANTIPLANE SHEAR(Ⅱ)—INSTABILITY

Based on the (Ⅰ) of the present work, the behavior of shear beam model at crack initiation stage and at instable propagation stage was studied. The prime results include: 1) discriminant equation which clarifies the mode of instability, snap_back or snap_through, was established; 2) analytical solution was given out for the double shear beam and the load_displacement diagram for monotonic loading was presented for a full process; and 3) the problem of the energy release induced by instability was discussed.

Role of acoustic interface layer during high intensity focused ultrasound therapeutics

After interface layer was simulated by the magnetic nano-particles in the egg white phantom, high intensity focused ultrasound （HIFU） at the same dosage was introduced to radiate the phantom in different depths to blow the acoustic interface layer to mimic ＂point＂ exposure. The results showed that the volumes of biological focal region （BFR） were enlarged when the acoustic focal region （AFR） is close with interface layer. This meant that the magnetic nano-particles enhanced the therapeutic efficiency of HIFU. When the distance of the AFR from the interface layer was 10 mm, the size and shape of the BFR were similar with those of the control group, but a larger lesion at the interface, which was harmful for treatment, was observed. When the distance of the AFR to the interface layer increased to 30 mm, the size and shape of the BFR were also similar to those of the control group. When the thickness of the interface layer diminished, the utility of enhancement decreased. Continuous increase of the safe area for treatment and decrease of the utility of enhancement were observed along with the abatement of the thickness of the interface layer

SHEAR BEAM MODEL FOR INTERFACE FAILURE UNDER ANTIPLANE SHEAR(Ⅰ)—FUNDAMENTAL BEHAVIOR

The propagation of interlayer cracks and the resulting failure of the interface is a typical mode occurring in rock engineering and masonry structure. On the basis of the theory of elasto^plasticity and fracture mechanics, the shear beam model for the solution of interface failure was presented. The concept of `cohesive crack' was adopted to describe the constitutive behavior of the cohesive interfacial layer. Related fundamental equations such as equilibrium equation, constitutive equations were presented. The behavior of a double shear beam bonded through cohesive layer was analytically calculated. The stable propagation of interface crack and process zone was investigated.

THE INTERFACE LAYERS AND CATHODOLUMINESCENCE STUDIES OF DIAMOND FILMS

Polycrystalline diamond films have been synthesized on various substrates by hot filament CVD from the mixture gases of methane and hydrogen. The interface layers between CVD diamond films and substrates have been investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, visible luminescence between 2.0～3.5eV of undoped and boron-doped CVD diamond films has also been studied by cathodoluminescence.

Thermal Conductance of Cu and Carbon Nanotube Interface Enhanced by a Graphene Layer

Thermal conduetances between Cu and graphene covered carbon nanotubes （gCNTs） are calculated by molecular dynamics simulations. The results show that the thermal conductance is about ten times larger than that of Cu- CNT interface. The enhanced thermal conductance is due to the larger contact area introduced by the graphene layer and the stronger thermal transfer ability of the Cu-gCNT interface. From the linear increasing thermal conductance with the increasing total contact area, an effective contact area of such an interface can be defined.

Nano silica aerogel-induced formation of an organic/alloy biphasic interfacial layer enables construction of stable high-energy lithium metal batteries

Lithium metal batteries represent promising candidates for high-energy-density batteries, however, many challenges must still be overcome,e.g., interface instability and dendrite growth. In this work, nano silica aerogel was employed to generate a hybrid film with high lithium ion conductivity(0.6 mS cm^(-1)at room temperature) via an in situ crosslinking reaction. TOF-SIMS profile analysis has revealed conversion mechanism of hybrid film to Li–Si alloy/Li F biphasic interface layer, suggesting that the Li–Si alloy and Li F-rich interface layer promoted rapid Li+transport and shielded the Li anodes from corrosive reactions with electrolyte-derived products. When coupled with nickel-cobalt-manganese-based cathodes, the batteries achieve outstanding capacity retention over 1000 cycles at 1 C. Additionally the developed film coated on Li enabled high coulombic efficiency(99.5%) after long-term cycling when coupled with S cathodes. Overall, the results presented herein confirm an effective strategy for the development of high-energy batteries.

Modulating magnetic interface layer on porous carbon heterostructures for efficient microwave absorption

Modern communication systems call for high performance electromagnetic wave absorption materials capable of mitigating microwaves over a wide frequency band. The synergistic effect of structure and component regulation on the electromagnetic wave absorption capacity of materials is considered. In this paper, a new type of three-dimensional porous carbon matrix composite is reported utilizing a reasonable design of surface impedance matching. Specifically, a thin layer of densely arranged Fe-Cr oxide particles is deposited on the surface of porous carbon via thermal reduction to prepare the Fe-Cr-O@PC composites. The effect of Cr doping on the electromagnetic wave absorption performance of the composites and the underlying attenuation mechanism have been uncovered. Consequently, outstanding electromagnetic wave absorption performance has been achieved in the composite, primarily contributed by the enhanced dielectric loss upon Cr doping. Accordingly, an effective absorption bandwidth of 4.08 GHz is achieved at a thickness of 1.4 mm, with a minimum reflection loss value of −52.71 dB. This work not only provides inspiration for the development of novel absorbers with superior performance but also holds significant potential for further advancement and practical application.

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

Microstructure and properties of Cu/Al joints brazed with Zn-Al filler metals

The mechanical properties and microstructural distribution of the Cu/A1 brazing joints formed by torch-brazing with different Zn-A1 filler metals were investigated. The microstructure of the Zn-A1 alloys was studied by optical microscopy and scanning electron microscopy, and the phase constitution of the Cu/A1 joints was analyzed by energy dispersion spectrometry. The results show that the spreading area of the Zn-A1 filler metals on the Cu and A1 substrates increases as the A1 content increases. The mechanical results indicate that the shear strength reaches a peak value of 88 MPa when A1 and Cu are brazed with Zn-15AI filler metal. Microhardness levels from HV122 to HV515 were produced in the three brazing seam regions corresponding to various microstructure features. The Zn- and Al-rich phases exist in the middle brazing seam regions. However, two interface layers, CuZn3 and A12Cu are formed on the Cu side when the A1 content in the filler metals is 2% and more than 15%, respectively. The relationship between intermetallic compounds on Cu side and Zn-xA1 filler metals was investigated.

Construction of zinc metal-Tin sulfide polarized interface for stable Zn metal batteries

Aqueous Zn metal batteries have become competitive electrochemical energy storage systems owing to their material abundance,low cost,high capacity,and nontoxicity.Nevertheless,the notorious Zn dendrites and poor anode reversibility caused by the insulating by-products and“dead Zn”are still formidable challenges for their practical application.Herein,an SnS-based layer coated on the Zn anode is reported to tackle these problems.The semiconducting SnS with a higher work function can drive the electrons from the Zn anode,which constructs a polarized interface between the SnS layer and Zn.The semiconducting importance of the coating layer is verified through theoretical simulations,which can migrate the polarization layer from the electrode surface to a wellprotected spot beneath the coating layer.This polarization interface is effective in homogenizing the Zn^(2+)flux and repelling the anions from electrochemical corrosion.Compared with the bare Zn,the SnS-coated Zn anode exhibits a notable 14.7-fold enhancement in plating/stripping lifetime(over 3000 h),high reversibility(with CE of 99.74%),and superior stability in full cells when paired with vanadium-and manganese-based cathodes.

Current advancements on charge selective contact interfacial layers and electrodes in flexible hybrid perovskite photovoltaics

Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency.Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field.Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency,light-weight,flexibility,semitransparency,compatibility towards roll-to-roll printing,and large-area mass-scale production.Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate,semi-transparent bottom contact electrode,perovskite(light absorber layer)and charge transport(electron/hole)layers and top(usually metal)electrode.Among these components,interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance.In this comprehensive review article,we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable,efficient flexible devices.As a concluding remark,we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.

Uniform, fast, and reliable CMOS compatible resistive switching memory

Resistive switching random access memory(RRAM) is considered as one of the potential candidates for next-generation memory. However, obtaining an RRAM device with comprehensively excellent performance, such as high retention and endurance, low variations, as well as CMOS compatibility, etc., is still an open question. In this work, we introduce an insert TaO_(x) layer into HfO_(x)-based RRAM to optimize the device performance. Attributing to robust filament formed in the TaO_(x) layer by a forming operation, the local-field and thermal enhanced effect and interface modulation has been implemented simultaneously. Consequently, the RRAM device features large windows(> 10^(3)), fast switching speed(-10 ns), steady retention(> 72h), high endurance(> 10^(8) cycles), and excellent uniformity of both cycle-to-cycle and device-to-device. These results indicate that inserting the TaO_(x) layer can significantly improve HfO_(x)-based device performance, providing a constructive approach for the practical application of RRAM.

A New Model of Interfacial Physical Contact in Diffusion Bonding

Through eliminating voids not affecting the primary bonding process, and incorporating interlayer and flexible base material, the interface geometry character and brief mathematics process were put forth. Through analyzing contact process of diffusion bonding, contact area model was settled. It can interpret the phenomenon of different interface areas taking on different strengths. In the course of physical contact, shear stresses serve an important function for the plastic deformation and the cohesion of interface voids.

Sound reflection from layered solid medium with rigid and slip interfaces

In this paper, a general model on sound reflection from a layered solid medium with rigid and slip interfaces is proposed by using matrix method. Analytical expressions for reflection coefficients of both longitudinal and transverse waves from the layered solid medium with one or two slip interfaces are derived. Numerical results of sound reflection coefficients from some typical adhesive joints with slip and rigid interfaces are presented, which may be useful for correct choice of technical parameters in ultrasonic evaluation of their interface properties.