Coupling Fe(II)/Fe(III) Redox Mediated SO2 Conversion with Hydrogen Production

Water electrolysis is recognized as a green hydrogen production technology, but the high voltage required for anodic oxygen evolution reaction restricts the practical application. In this work, a Fe(II)/Fe(III) redox mediated SO₂ conversion is proposed to couple the cathodic hydrogen evolution reaction to achieve sulfur dioxide conversion and hydrogen production at low voltage. The onset potential of Fe(II) electrooxidation to Fe(III) is as low as 0.75 V_RHE (vs reversible hydrogen electrode). Ex situ ultraviolet spectroscopy (UV) spectrum and ion chromatography indicate that SO₂ in electrolyte can reduce Fe(III) to Fe(II), completing the Fe(II)/Fe(III) redox cycle as well as the conversion of SO₂ to sulfuric acid. The assembled flow cell electrolyzer requires a low operating voltage of 0.97 V at 10 mA cm⁻² and shows good performance under both acidic and neutral conditions. This study proposes an innovative energy saving and environment friendly strategy for simultaneous hydrogen production and sulfur dioxide capture based on low-cost catalyst materials.     

CuInS2 nanoparticles: Microwave-assisted synthesis,characterization, and photovoltaic measurements

For the first time, (1,8-diamino-3,6-dioxaoctan)copper(II) sulfate, [Cu(DADO)]SO₄, and bis(propylenediamine)copper(II) sulfate, [Cu(pn)₂]SO₄, complexes as copper precursors have been used to prepare CuInS₂ (CIS) nanoparticles in the presence of microwave irradiation. InCl₃ anhydrous, thioacetamide (TAA), and propylene glycol were used as indium source, sulfur precursor, and solvent, respectively. Additionally, sodium dodecyl sulfate (SDS) was used as a capping agent. In this method, microwave irradiation created the activation energy for dissociating the precursors and led to the formation of CuInS₂ nanoparticles. The effect of preparation parameters such as microwave power, irradiation time, and type of copper precursor on the particle size of the products was studied. To fabricate a solar cell, CdS film was directly deposited on top of the CIS film through the chemical bath deposition method. The as-deposited CdS/CuInS₂ films were used for the photovoltaic measurements. According to I–V curves, it was found that the CIS nanoparticles synthesized by [Cu(DADO)]SO₄ complex as precursor was better for solar cell applications.     

N,7,7‐Tricyanoquinomethanimine (TCQMI) Based Organic Magnetic Materials

The synthesis and characterization of a new family of magnetic materials based on the electron accepting cyanocarbon N,7,7‐tricyanoquinomethanimine, TCQMI, its radical anion [TCQMI], and its σ‐dimer, σ‐[TCQMI]₂^2?, are reported. [Fe^IIICp*₂][TCQMI] (where Cp* is pentamethylcyclopentadienide) forms parallel chains of alternating [TCQMI]^?? and [FeCp*₂]^?+ and magnetically orders at 3.4 K as a weak ferromagnet. M[TCQMI]₂?zCH₂Cl₂ (M = V, Fe) are amorphous solids with [TCQMI]^?? coordinated to metal centers through the nitrile groups. The Fe compound magnetically orders as a weak ferromagnet at ≈4 K, whereas the V compound shows no evidence of magnetic ordering. {[Mn^IIITPP]⁺}₂[TCQMI]₂^2? (TPP = tetraphenylporphyrin) results from the reaction of TCQMI with Mn^IITPP(py) due to the formation of the [TCQMI]₂^2? σ‐dimer in situ, and is a weak ferromagnet below 3.7 K. The lack of magnetic ordering in V[TCQMI]₂?zCH₂Cl₂ is not currently understood, and is in strong contrast to V[TCNE]₂?zCH₂Cl₂, which magnetically orders above room temperature.     

Functional Pyrimidinyl Pyrazolate Pt(II) Complexes: Role of Nitrogen Atom in Tuning the Solid‐State Stacking and Photophysics

Pt(II) metal complexes are known to exhibit strong solid‐state aggregation and are promising for realization of efficient emission in fabrication of organic light emitting diodes (OLED) with nondoped emitter layer. Four pyrimidine–pyrazolate based chelates, together with four isomeric Pt(II) metal complexes, namely: [Pt(pm2z)₂], [Pt(tpm2z)₂], [Pt(pm4z)₂], and [Pt(tpm4z)₂], are isolated and systematically investigated for their structure–property relationships for practical OLED applications. Detailed single molecular and aggregated structures are revealed by photophysical and mechanochromic measurements, grazing‐incidence X‐ray diffraction, and theoretical approaches. These results suggest that these Pt(II) emitters pack like a deck of playing cards under vacuum deposition, and their emission energy is not only affected by the single molecular designs, but notably influenced by their intermolecular packing interaction, i.e., Pt···Pt separations that are arranged in the order: [Pt(tpm4z)₂] > [Pt(pm4z)₂] > [Pt(tpm2z)₂] > [Pt(pm2z)₂]. Nondoped OLED with emission ranging from green to red are prepared, to which the best performances are recorded for [Pt(tpm2z)₂], giving maximum external quantum efficiency (EQE) of 27.5% at 10³ cd m^?2, maximum luminance of 2.5 × 10⁵ cd m^?2 at 17 V, and with stable CIE_x,y of (0.56, 0.44).     

弱碱性抛光液中FA/O 螯合剂和H2O2对Ru CMP的影响研究

Ru作为一种新型阻挡层材料已经应用到了先进的集成电路生产中。但由于金属钌特殊的物理化学性质使其化学机械抛光(CMP)还存在很多问题。为了提高Ru的去除速率,本文研究了FA/O螯合剂和H2O2对Ru的抛光去除速率(RR)和静态腐蚀速率(SER)的影响。实验结果表明,随着H2O2浓度的增加,在抛光过程中,Ru表面形成了致密氧化层,导致Ru的抛光去除速率(RR)和静态腐蚀速率(SER)先增加后减少。通过电化学方法对Ru表面的腐蚀情况进行了分析研究。结果表明,FA/O螯合剂能通过与Ru的氧化物((RuO4)2- 和RuO4 )形成可溶性胺盐([R(NH3)4] (RuO4)2) 提高Ru 的去除速率。同时,为了降低金属Ru CMP后表面粗糙度,在抛光液中加入了非离子表面活性剂AD。     

Synthesis of dibenzothiophene-based host materials and their blue phosphorescent device performances

Two structural isomeric host materials, 9-(4-(dibenzo[b,d]thiophen-4-yl)phenyl)-9H-pyrido-[2,3-b]indole (pDBTCb) and 9-(3-(dibenzo[b,d]thiophen-4-yl)phenyl)-9H-pyrido-[2,3-b]indole (mDBTCb), were designed and synthesized, incorporating dibenzothiophene (DBT) and α-carboline moieties via phenyl linkages and their device performances of phosphorescent organic light-emitting diodes (PHOLEDs) were also investigated. The different linkages between DBT and α-carboline on central phenyl spacer play an important role in the structure–property correlations. Although their photophysical properties were similar regardless of different linkage positions, the bis[2-(4,6-difluorophenyl)pyridinato-C²,N](picolinato)iridium(III)-based blue device with mDBTCb, which adopted a meta-linkage showed a significantly higher maximum quantum efficiency of 19.8% as compared to its para-linkage analog, pDBTCb (16.2%). A high quantum efficiency of 19.8% and only ca. 10% reduction of quantum efficiency at 1000 cd/m² were demonstrated from the blue PHOLEDs with the mDBTCb host material.     

Orange and Red Organic Light‐Emitting Devices Employing Neutral Ru(II) Emitters: Rational Design and Prospects for Color Tuning

A new series of charge‐neutral Ru(II ) pyridyl and isoquinoline pyrazolate complexes, [Ru(bppz)₂(PPh₂Me)₂] (bbpz: 3‐tert‐butyl‐5‐pyridyl pyrazolate) ( 1 ), [Ru(fppz)₂(PPh₂Me)₂] (fppz: 3‐trifluoromethyl‐5‐pyridyl pyrazolate) ( 2 ), [Ru(ibpz)₂(PPhMe₂)₂] (ibpz: 3‐tert‐butyl‐5‐(1‐isoquinolyl) pyrazolate) ( 3 ), [Ru(ibpz)₂(PPh₂Me)₂] ( 4 ), [Ru(ifpz)₂(PPh₂Me)₂] (ifpz: 3‐trifluoromethyl‐5‐(1‐isoquinolyl) pyrazolate) ( 5 ), [Ru(ibpz)₂(dpp?)] (dpp? represents cis‐1,2‐bis‐(diphenylphosphino)ethene) ( 6 ), and [Ru(ifpz)₂(dpp?)] ( 7 ), have been synthesized, and their structural, electrochemical, and photophysical properties have been characterized. A comprehensive time‐dependant density functional theory (TDDFT) approach has been used to assign the observed electronic transitions to specific frontier orbital configurations. A multilayer organic light‐emitting device (OLED) using 24 wt % of 5 as the dopant emitter in a 4,4′‐N,N′‐dicarbazolyl‐1,1′‐biphenyl (CBP) host with 4,4′‐bis[N‐(1‐naphthyl)‐N‐phenylamino]biphenyl (NPB) as the hole‐transport layer exhibits saturated red emission with an external quantum efficiency (EQE) of 5.10 %, luminous efficiency of 5.74 cd A^–1, and power efficiency of 2.62 lm W^–1. The incorporation of a thin layer of poly(styrene sulfonate)‐doped poly(3,4‐ethylenedioxythiophene) (PEDOT) between indium tin oxide (ITO) and NPB gave anoptimized device with an EQE of 7.03 %, luminous efficiency of 8.02 cd A^–1, and power efficiency of 2.74 lm W^–1 at 20 mA cm^–2. These values represent a breakthrough in the field of OLEDs using less expensive Ru(II ) metal complexes. The nonionic nature of the complexes as well as their high emission quantum efficiencies and short radiative lifetimes are believed to be the key factors enabling this unprecedented achievement. The prospects for color tuning based on Ru(II ) complexes are also discussed in light of some theoretical calculations.     

Effect of substituents on the properties of indolo[3,2-b]carbazole-based hole-transporting materials

Three new compounds based on indolo[3,2-b]carbazole,2,8-bis(4-diphenylaminophenyl)-5,11-di-n-octylindolo[3,2-b]carbazole (BTOICZ), 2,8-bis(9,9′-di-n-butylfluorenyl)-5,11-di-n-octylindolo[3,2-b]carbazole (BFOICZ) and 2,8-bis[N-(n-butyl)carbazolyl]-5,11-di-n-octylindolo[3,2-b]carbazole (BCOICZ), as hole-transporting materials have been synthesized by Suzuki coupling reaction. The effects of substituents on the optical, thermal and electrochemical properties of indolo[3,2-b]carbazole derivatives have been studied carefully. Electroluminescent (EL) devices using these compounds as hole-transporting layer in combination with Alq₃ as electron-transporting and emitting layer have been fabricated and characterized. The devices based on BTOICZ or BFOICZ showed green emission at 526 nm, while the device based on BCOICZ emitted very weak light. The turn-on voltages are 4.1 and 5.4 V for BTOICZ and BFOICZ, respectively. The maximal luminance efficiencies are 0.738 and 0.767 lm/W for BTOICZ and BFOICZ, respectively. The difference of the EL performances of these compounds reveals that the substituent effects have great effect on the hole-transporting performance of the indolo[3,2-b]carbazole-based compounds.     

New insights into acidic wet chemical silicon etching by HF/H2O–NOHSO4–H2SO4 solutions

Acidic wet chemical etching of crystalline silicon has been examined by utilization of HF–NOHSO₄–H₂SO₄ mixtures. In light of our previous studies the effects of nitrosyl ion concentrations on etching rates were studied time- and temperature resolved. The reactivity of crystalline silicon surfaces in HF/H₂SO₄ solutions is determined by NO⁺-ion concentrations at the silicon/electrolyte interface, measured by ion chromatography. Quantitative solution analysis proofed accumulation of ammonium ions and indicated the conversion of NO⁺ as limiting for the overall etching process. Direct participation in the rate-limiting step was confirmed by calculation of activation energies. Increasing NO⁺-ion contents cause transition from reaction (E_A=55 kJ mol^?1) to diffusion controlled (E_A=10 kJ mol^?1) etching procedures. In combination with time and concentration dependent studies of produced structures a convenient regime for selective texturing or polishing polycrystalline silicon surfaces is reported. Qualitative analysis by ¹⁹F-NMR and Raman spectroscopy identified SiF₅^?/HF₂^? complexes as well as elementary hydrogen (H₂) as hitherto unknown products of silicon dissolution reactions in HF–NOHSO₄–H₂SO₄ mixtures. Based on our findings a strategy for fundamental investigations of relevant reaction pathways is presented and discussed with regard to reported mechanistic concepts.     

Solution-processed single-crystalline organic transistors on patterned ultrathin gate insulators

Single-crystalline organic transistors of 3,11-didecyl-dinaphtho[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene (C₁₀-DNBDT-NW) and 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C₁₀-DNTT) were fabricated by solution processes on top of the patterned hybrid ultrathin gate dielectrics consisting of 3.6 nm-thick aluminum oxide and self-assembled monolayers (SAMs). Due to the excellent crystallinity of the channel films, bottom-gate and top-contact field-effect transistors exhibited the average field-effect mobility of 3.7 cm²/V s and 4.3 cm²/V s for C₁₀-DNBDT-NW and C₁₀-DNTT, respectively. These are the first successful devices of solution-processed single-crystalline transistors on ultrathin gate dielectrics with the mobility above 1 cm²/V s, opening the way to develop low-power-consumption and high-performance printed circuits.     

Novel dithieno[3,2-b:2′,3′-d]pyrrole-based organic dyes with high molar extinction coefficient for dye-sensitized solar cells

Three new metal-free organic dyes FD1–3 with a planar dithieno[3,2-b:2′,3′-d]pyrrole unit as linker were synthesized and used for dye-sensitized solar cells with high molar extinction coefficients. In this work, dithieno[3,2-b:2′,3′-d]pyrrole was employed as π-conjugated bridge to construct A–π–d–π–A organic dyes, where 9,9-dihexyl-9H-fluorene was used as a donor, and cyanoacrylic acid as an electron acceptor. For a typical device, a solar energy conversion efficiency (η) of 6.36% based on FD2 was achieved under simulated AM 1.5 solar irradiation (100 mW cm^?2) with a short-circuit photocurrent density (J_sc) of 13.76 mA cm^?2, an open-circuit voltage (V_oc) of 669 mV, a fill factor (ff) of 0.691. The results suggest that the organic dye with a functionalized dithienopyrrole unit is a promising candidate for DSSCs due to its high molar extinction coefficients.     

Structure and conductivity of liquid crystal channel-like linic complexes of taper-shaped compounds

Molecular packing and electrical conductivity were studied in complexes of alkali trifluoromethanesulphonates with low-molar or polymeric compounds containing both taper-shaped mesogens were esters of either 3,4,5-tris [p-(n-dodecan-l-yloxy) benzyloxy] benzoic acid (I) or 3, 4, 5-tris (n-dodecan-l-yloxy) benzoic acid (II). In the hexagonal columnar liquid crystal phase the tapered mesogens fan out from the centre of the column, with the ionic receptors forming the central channel and the aliphatic tails constituting the continuum matrix. In the case of side-chain polymethacrylates the column core also contains the backbone chain. The DC conductivity σ of unoriented samples increases greatly at the crystal-columnar transition, with only a minor further change upon columnar-isotropic transition. σ was in the range 10^?9 ? 10^?6 in the columnar phase 40–90 °C, whilst the activation energies for conduction were between 28 kcal mol^?1 for the crown ether and only 2 kcal mo^?1 for the complex of LiCf₃SO₃ with the non-polymeric ester of tri(ethylene oxide) with I.     

Highly luminescent platinum(II) complexes based on pyrazolo[1,5-f]phenanthridine-containing ligands

A series of highly luminescent [Pt(NˆCˆCˆN)] emitters (ZPt1, ZPt2 and ZPt3) based on pyrazolo[1,5-f]phenanthridine-containing ligands were designed and synthesized. These Pt(II) complexes demonstrated extremely high thermal stabilities with the 5% weight-reduction temperatures over 450 °C due to the incorporation of the rigid pyrazolo[1,5-f]phenanthridine motif and the robustness of the tetradentate coordination framework. These Pt(II) complexes have the same coordination set (pyridineˆbenzeneˆbenzeneˆpyrazole) but with slightly different linkage between coordination groups. Within ZPt1 and ZPt2, pyridine and the neighboring benzene groups are separated by oxygen and aniline, respectively. In ZPt3, pyridine group is rigidly grafted on the carbazole unit. The effect of the different linkages on the frontier orbital energies, the photophysical and electroluminescent properties of ZPt1-ZPt3 was investigated systematically. Organic light emitting diodes (OLEDs) based on these Pt(II) complexes were fabricated with typical device structure. The Pt(II) complexes displayed intense electroluminescence in the blue to yellowish green spectral region. Among the three Pt(II) complexes, the 3-(pyridin-2-yloxy)phenoxy-based ZPt1 compound showed the highest electroluminescence performance with the maximum CE, PE, and EQE of 58.0 cd A⁻¹, 51.6 lm W⁻¹, and 16.4%, respectively.     

Wet chemical etching of NiFe,NiFeCo AND NiMnSb for magnetic device fabrication

Thin film NiMnSb is found to be wet chemically etched in a range of solutions, including HNO₃, H₂SO₄:H₂O₂, FeCl₃ and HF, with activation energies in the range 10–23 kCal mol⁻¹, i.e. a reaction-limited regime. The degree of sidewall undercut is a function of solution type. Both NiFe and NiFeCo can be etched in H₂SO₄ and HNO₃, with reaction-limited characteristics, while HCl at 25°C is completely selective for NiFe over NiFeCo, even for 7% Co alloys. The degree of sidewall undercut on NiFe is also a strong function of solution type.     

Fluorine Segregation Controls the Solid‐State Organization and Electronic Properties of Ni and Au Dithiolene Complexes: Stabilization of a Conducting Single‐Component Gold Dithiolene Complex

Electrooxidation of the nickel dithiolene complex [Ni(F₂pdt)₂]^–· (F₂pdt^2‐: 6,6‐difluoro‐6,7‐dihydro‐5H‐[1,4]dithiepine‐2,3‐dithiolato) affords the corresponding neutral complex [Ni(F₂pdt)₂]⁰ whose layered structure is highly reminiscent, albeit not isostructural, of that of the isosteric fluorinated bis(propylenedithio)tetrathiafulvalene and characterized by a segregation of the fluorinated moieties into fluorous bilayers. The gold neutral complex [Au(F₂pdt)₂]^·, which is isostructural with the fluorinated bis(propylenedithio)tetrathiafulvalene, was prepared by electrocrystallization of the [n‐Bu₄N][Au(F₂pdt)₂] salt. [Au(F₂‐pdt)₂]^· is a semiconductor with high room temperature conductivity. The origin of this semiconducting behavior as well as possible guidelines in order to realize metallic conductivity in gold dithiolene neutral molecular solids are discussed.     

Biodegradable Fe(III)@WS2‐PVP Nanocapsules for Redox Reaction and TME‐Enhanced Nanocatalytic,Photothermal, and Chemotherapy

In this study, biocompatible Fe(III) species‐WS₂‐polyvinylpyrrolidone (Fe(III) @ WS₂‐PVP) nanocapsules with enhanced biodegradability and doxorubicin (DOX) loading capacity are one‐pot synthesized. In this nanocapsule, there exists a redox reaction between Fe(III) species and WS₂ to form Fe²⁺ and WO₄^2?. The formed Fe²⁺ could be oxidized to Fe³⁺, which reacts with Fe(III) @ WS₂‐PVP again to continuously produce Fe²⁺ and WO₄^2?. Such a repeated endogenous redox reaction leads to an enhanced biodegradation and DOX release of DOX @ Fe(III) @ WS₂‐PVP. More strikingly, the Fe²⁺ generation and DOX release are further accelerated by the overexpressed H₂O₂ and the mild acidic tumor microenvironment (TME), since H₂O₂ and H⁺ can accelerate the oxidation of Fe²⁺. The continuously generated Fe²⁺ catalyzes a fast Fenton reaction with the innate H₂O₂ in tumor cells and produces abundant highly toxic hydroxyl radicals for nanocatalytic tumor therapy. Together with the high photothermal transforming capability, the DOX @ Fe(III) @WS₂‐PVP nanocapsules successfully achieve the endogenous redox reaction and exogenous TME‐augmented tumor photothermal therapy, chemo and nanocatalytic therapy outcome. The concept of material design can be innovatively extended to the synthesis of biodegradable Fe(III) @ MoS₂‐PVP nanocomposite, thus paving a promising novel way for the rational design of intelligent theranostic agents for highly efficient treatment of cancer.     

In Situ Grown Pristine Cobalt Sulfide as Bifunctional Photocatalyst for Hydrogen and Oxygen Evolution

Herein, transition metal chalcogenides of pristine cobalt sulfides are rationally designed to act as robust bifunctional photocatalysts for visible‐light‐driven water splitting for the first time. Through moderate solvothermal route, cobalt sulfides are synthesized in situ growth and observed by scanning electron microscope image analysis. Noteworthily, 3D hierarchical cobalt sulfides acting as bifunctional photocatalysts are implemented to catalyze the visible‐light‐driven oxygen evolution reaction and hydrogen evolution reaction. This efficient, earth‐abundant, and nonnoble water splitting catalyst for artificial photosynthesis is thoroughly analyzed by various spectroscopic techniques with the aim of investigating its photocatalytic mechanism under visible‐light illumination. The main catalyst of CoS‐2 exhibits considerable H₂ evolution rate of 1196 µmol h^?1 g^?1 and O₂ yield of 63.5%. The efficient activity is attributed to the effective electron transfer between the photosensitizer and catalyst, which is verified by transient absorption experiments. The effective electron transfer between the photosensitizer and catalyst during water oxidation is verified by the dramatic decline of [Ru(bpy)₃]³⁺ concentration in the presence of the catalyst CoS‐2. At the same time, transient absorption experiments support a rapid electron transfers from ³EY* (excited photosensitizer eosin‐Y) to the catalyst CoS‐2 for efficient hydrogen evolution.     

Active Motif Change of Ni-Fe Spinel Oxide by Ir Doping for Highly Durable and Facile Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is crucial for producing sustainable energy carriers. Herein, Ir (5 mol.%) doped inverse-spinel NiFe₂O₄ (Ir-NFO) nanoparticles deposited on Ni foam (NF) by scalable solution casting are considered a promising OER electrocatalyst for industrial deployments. The Ir-NFO/NF (with minimal lattice distortion by uniform Ir doping) provides an OER overpotential of 251 mV (intrinsically outperforming NFO/NF and benchmarking IrO₂/NF) and extraordinary robustness over 130 days at 100 mA cm⁻². In situ X-ray absorption spectroscopy reveals oxidation only for Fe on NFO, whereas concurrent generation of higher-valent Ni and Fe occurs on Ir-NFO during OER. Density functional theory calculations further demonstrate that Ir substitutes the sublayer Ni octahedral site and switches the main active reaction center from Fe_Oh Fe_Td bridge site (Fe O Fe) on NFO to Ni_Oh–Fe_Td bridge site (Ni O Fe active motif) on Ir-NFO for a co-catalytic OER. This study sheds new light on precious-metal doped Ni-Fe oxides, which may be applicable to other binary/ternary oxide electrocatalysts.     

Atomically Thin Defect‐Rich Fe–Mn–O Hybrid Nanosheets as High Efficient Electrocatalyst for Water Oxidation

Engineering non‐noble metal–based electrocatalysts with superior water oxidation performance is highly desirable for the production of renewable chemical fuels. Here, an atomically thin low‐crystallinity Fe–Mn–O hybrid nanosheet grown on carbon cloth (Fe–Mn–O NS/CC) is successfully synthetized as an efficient oxygen evolution reaction (OER) catalyst. The synthesis strategy involves a facile reflux reaction and subsequent low‐temperature calcination process, and the morphology and composition of hybrid nanosheets can be tailored conveniently. The defect‐rich Fe–Mn–O ultrathin nanosheet with uniform element distribution enables exposure of more catalytic active sites; moreover, the atomic‐scale synergistic action of Mn and Fe oxide contributes to an enhanced intrinsic catalytic activity. Therefore, the optimized Fe–Mn–O hybrid nanosheets, with lateral sizes of about 100–600 nm and ≈1.4 nm in thickness, enable a low onset potential of 1.46 V, low overpotential of 273 mV for current density of 10 mA cm^?2, a small Tafel slope of 63.9 mV dec^?1, and superior durability, which are superior to that of individual MnO₂ and FeOOH electrode, and even outperforming most reported MnO₂‐based electrocatalysts.     

Orientation-Engineered Small-Molecule Semiconductors as Dopant-Free Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells

Crystallized p-type small-molecule semiconductors have great potential as an efficient and stable hole transporting materials (HTMs) for perovskite solar cells (PSCs) due to their relatively high hole mobility, good stability, and tunable highest occupied molecular orbitals. Here, a thienoacene-based organic semiconductor, 2,9-diphenyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DPh-DNTT), is thermally evaporated and employed as the dopant-free HTM that can be scaled up for large-area fabrication. By controlling the deposition temperature, the molecular orientation is modulated into a dominant face-on orientation with π–π stacking direction perpendicular to the substrate surface, maximizing the out-of-plane carrier mobility. With an engineered face-on orientation, the DPh-DNTT film shows an improved out-of-plane mobility of 3.3 × 10⁻² cm² V⁻¹ s⁻¹, outperforming the HTMs reported so far. Such orientation-reinforced mobility contributes to a remarkable efficiency of 20.2% for CH₃NH₃PbI₃ inverted PSCs with enhanced stability. The results reported here provide insights into engineering the orientation of molecules for the dopant-free organic HTMs for PSCs.