High Work Function Research Articles

Ag:MoO3:Yb semi-transparent electrode for top emission organic light-emitting didoes

Silver (Ag) is widely used as a cathode in top-emission organic light-emitting diodes (TEOLEDs) for its high reflectivity and conductivity. However, its high absorption, thickness-dependent transmittance, and high work function require further improvement. While Ag:MoO3 alloy has emerged as an alternative, it still needs further enhancement. In this study, we developed a ternary Ag:MoO3:Yb semi-transparent electrode, improving both the optical and electrical properties of the existing binary system. For example, The 30 nm-thick Ag:MoO3:Yb 4:3:3 film exhibited average transmittance, reflectance, and absorption of 64%, 12%, and 24%, respectively. Additionally, the Ag:MoO3:Yb showed a uniform transmittance spectrum in the visible wavelength range. The photoelectron spectroscopy results showed Ag:MoO3:Yb 4:3:3 film has a low work function of 3.69eV. Despite relatively high sheet resistance around 82~130 Ω/sq, the red phosphorescence TEOLEDs incorporating Ag:MoO3:Yb as cathode showed improved device performances compared to the control device with Ag:MoO3 30% where the current efficiency increased by up to 1.7 times and the power efficiency by up to 2.6 times. Furthermore, the optimized Ag:MoO3:Yb devices with good charge balance resulted in a relatively longer lifetime up to 80% of initial luminance (LT80) of 166hr, which are higher performance than those of the device with Ag:MoO3 30%.

Enhanced Voltage‐Controlled Magnetic Anisotropy and Field‐Free Magnetization Switching Achieved with High Work Function and Opposite Spin Hall Angles in W/Pt/W SOT Tri‐Layers

Enhanced Voltage‐Controlled Magnetic Anisotropy and Field‐Free Magnetization Switching Achieved with High Work Function and Opposite Spin Hall Angles in W/Pt/W SOT Tri‐Layers

Robust Sodium Storage Enabled by Heterogeneous Engineering and Electrolyte Modification

AbstractThe modulation of heterointerfaces in 2D materials is critically important for improving the electrochemical performance of sodium‐ion batteries (SIBs). In this context, the MoS2/Ti3C2Tx MXene heterostructure is taken as a typical example to reveal the fundamental principle of high sodium storage performance by regulating the terminal groups of Ti3C2Tx. It is demonstrated that MoS2/Ti3C2(OH)x (M/‐(OH)x) heterostructure with a high work function difference generates an enhanced built‐in electric field, which facilitates charge transfer. Moreover, ether‐based electrolytes, when compared to ester‐based electrolytes, provide lower solvation‐free energies and exhibit high compatibility with M/‐(OH)x, resulting in superior rate capability. Notably, COMSOL simulations of sodium ion (Na+) concentration and Na+ flux distributions reveal that the M/‐(OH)x electrode has low concentration polarization and rapid diffusion kinetics in ether‐based electrolytes. Consequently, the combination of M/‐(OH)x heterostructure with the ether‐based electrolyte provides 224.06 mAh g−1 after 1000 cycles at 5.0 A g−1. Furthermore, the Na3V2(PO4)3/C//M/‐(OH)x full cell demonstrates robust electrochemical performance, delivering 116.49 mAh g−1 after 140 cycles at 1.0 A g−1. These findings emphasize the impact of modulating terminal functional groups to optimize the electrochemical functionality of heterostructures and highlight the crucial role of electrode/electrolyte synergistic coupling in advancing the practical applications of SIBs.

Reversible Redox Probes to Determine Band‐Edge Locations and Dopant Concentrations of Nano‐TiO2 Thin‐Films: Settling the Mott‐Schottky Conundrum

AbstractKnowing the exact location of the semiconductor band‐edges is key for mechanistic insights into their use for water and CO2 photo/electrocatalysis. In this regard, a reliable strategy for nano‐semiconductors did not exist yet. We demonstrate the use of reversible redox probes on nano‐semiconductor electrodes to determine their band‐edge locations in aqueous solutions. Rectifying current‐potential (i‐U) characteristics with the high work function (i.e. more positive formal potential) Fe(CN)63−/Fe(CN)64− redox couple yielded the exact flatband potential at various pH whereas the reversible i‐U characteristics with the low work function (i.e. more negative formal potential) Ru(NH3)63+/Ru(NH3)62+ redox couple provided the conduction band‐edge location and dopant concentration for a 30 nm thin‐film n‐TiO2. The methodology can be extended to other nano‐semiconductors and serves as an alternative to and goes beyond the capabilities of the Mott‐Schottky procedure for bulk semiconductor electrodes.

Application of PACz-Based Self-Assembled Monolayer Materials in Efficient Perovskite Solar Cells.

Due to the advantages of low interface resistance, high work function, and high stability, PACz family materials have developed rapidly in p-i-n structure perovskite solar cells (PSCs) in recent years. Numerous studies have shown that PSCs prepared on the basis of PACz family materials or their derivatives as hole transport layers (HTLs) generally exhibit superior performance compared to PSCs prepared on the basis of organic HTL PTAA and inorganic HTL NiOx, especially in terms of stability, demonstrating unparalleled charm. Since the application of PACz-like molecule V1036 as a HTL in PSCs in 2018, research reports on high-performance PSCs based on the PACz family HTL have been widely disseminated. Currently, PSCs based on the PACz HTL exhibit a world record value of 26.7% power conversion efficiency (PCE), breaking the long-standing world record held by n-i-p-structured PSCs, indicating its great potential for application in PSCs. The main problem with using PACz as a HTL is that it exhibits poor wettability toward perovskite precursor solutions, is sensitive to the thickness of the HTL and the roughness of the substrate, has poor thermal stability, and lacks preparation methods, making it difficult to achieve large-area device fabrication. This review summarizes the outstanding achievements of PACz to date, describes the mechanism and unique properties of PACz in PSCs, and looks forward to the future development prospects of PACz.

Ethanol Processable Inorganic-Organic Hybrid Hole Transporting Layers Enabled 20.12 % Efficiency Organic Solar Cells.

In this study, a high-performance inorganic-organic hybrid hole transporting layer (HTL) was developed using ethanol-soluble alkoxide precursors and a self-assembled monolayer (SAM). Three metal oxides-vanadium oxide (VOx), niobium oxide (Nb2O5), and tantalum oxide (Ta2O5)-were synthesized through successive low-temperature (100 °C) thermal annealing (TA) and UV-ozone (UVO) treatments of their respective precursors: vanadium oxytriethoxide (EtO-V), niobium ethoxide (EtO-Nb), and tantalum ethoxide (EtO-Ta). Among these, the Nb2O5 film exhibited excellent transmittance, a high work function, and good conductivity, along with a more compact and uniform structure featuring fewer interfacial defects, which facilitated efficient charge extraction and transport. Furthermore, the deposition of a SAM of (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) on top of Nb2O5 further passivated defects, enhancing interfacial contact with the photoactive layer. The resulting inorganic-organic hybrid HTL of Nb2O5/2PACz demonstrated excellent compatibility with various photoactive blends, achieving impressive power conversion efficiencies of 19.44 %, 19.18 %, and 20.12 % for the PM6:L8-BO, PM6:BTP-eC9, and D18:BTP-eC9 based organic solar cells, respectively. 20.12 % is the best performance for bulk heterojunction organic solar cells with binary components as the photoactive layer.

Ethanol Processable Inorganic‐Organic Hybrid Hole Transporting Layers Enabled 20.12 % Efficiency Organic Solar Cells

AbstractIn this study, a high‐performance inorganic‐organic hybrid hole transporting layer (HTL) was developed using ethanol‐soluble alkoxide precursors and a self‐assembled monolayer (SAM). Three metal oxides‐vanadium oxide (VOx), niobium oxide (Nb2O5), and tantalum oxide (Ta2O5)‐were synthesized through successive low‐temperature (100 °C) thermal annealing (TA) and UV‐ozone (UVO) treatments of their respective precursors: vanadium oxytriethoxide (EtO−V), niobium ethoxide (EtO−Nb), and tantalum ethoxide (EtO−Ta). Among these, the Nb2O5 film exhibited excellent transmittance, a high work function, and good conductivity, along with a more compact and uniform structure featuring fewer interfacial defects, which facilitated efficient charge extraction and transport. Furthermore, the deposition of a SAM of (2‐(9H‐carbazol‐9‐yl)ethyl)phosphonic acid (2PACz) on top of Nb2O5 further passivated defects, enhancing interfacial contact with the photoactive layer. The resulting inorganic‐organic hybrid HTL of Nb2O5/2PACz demonstrated excellent compatibility with various photoactive blends, achieving impressive power conversion efficiencies of 19.44 %, 19.18 %, and 20.12 % for the PM6:L8‐BO, PM6:BTP‐eC9, and D18:BTP‐eC9 based organic solar cells, respectively. 20.12 % is the best performance for bulk heterojunction organic solar cells with binary components as the photoactive layer.

Reversible Redox Probes to Determine Band-Edge Locations and Dopant Concentrations of Nano-TiO2 Thin-Films: Settling the Mott-Schottky Conundrum.

Knowing the exact location of the semiconductor band-edges is key for mechanistic insights into their use for water and CO2 photo/electrocatalysis. In this regard, a reliable strategy for nano-semiconductors did not exist yet. We demonstrate the use of reversible redox probes on nano-semiconductor electrodes to determine their band-edge locations in aqueous solutions. Rectifying current-potential (i-U) characteristics with the high work function Fe(CN)63-/Fe(CN)64- redox couple yielded the exact flatband potential at various pH whereas the reversible i-U characteristics with the low work function Ru(NH3)63+/Ru(NH3)62+ redox couple provided the conduction band-edge location and dopant concentration for a 30nm thin-film n-TiO2. The methodology can be extended to other nano-semiconductors and serves as an alternative to and goes beyond the capabilities of the Mott-Schottky procedure for bulk semiconductor electrodes.

Spontaneous built-in electric field in W-W2C@C heterostructure: Accelerating Sn2- directed migration in Li-S batteries

The commercialization of Li-S batteries is severely hindered by shuttle effect and sluggish redox reaction kinetics of LiPSs. Heterostructure can resolve the above shortcomings through the synergistic effect of adsorption and catalysis. However, long-chain LiPSs dissolving in electrolyte tend to cluster, resulting in low sulfur utilization and preventing kinetic conversion Thus, it is necessary to regulate the diffusion of Sn2− to achieve the directional diffusion from adsorbent to catalyst. Nevertheless, the design principle has not yet been clarified. W-W2C@C heterostructure with W of strong adsorption ability and high work function and W2C of excellent catalytic activity and low work function is designed by theoretical screening. Due to work function difference, this heterostructure controls the direction of the interface built-in electric field (BIEF), realizing the directional migration process of Sn2− from adsorptive W to catalytic W2C, thereby achieving a continuous “trapping-directional migration-conversion” reaction mechanism. The batteries have an excellent Li+ diffusion rate, high initial discharge specific capacity (1400.6 mAh/g at 0.2C), excellent rate capability (853.2 mAh/g at 2C), high reversible capacity (977.9 mAh/g after 150 cycles at 0.2C) and an extremely low capacity decay rate of 0.09 % per cycle after 300 cycles at 1C.

Acid-Triggered Side Chain Cleavage Leads to Doped Conjugated Polymers of High Conductivity.

Cleavable side chain based conjugated polymers (CSCPs) represent a unique approach to offering solution processability with added benefits via the elimination of insulating side chains. This work highlights an optimally designed polythiophene-carboxylic acid based CSCP, POET-T2-COOH, which achieves a conductivity exceeding 350 S/cm in molecularly doped and side chain cleaved films, 100-100,000 times higher than three other structurally isomeric CSCPs. The high conductivity of POET-T2-COOH is accomplished via a new "cleavage with doping" methodology, synergistically combining a strong acid and a primary dopant. This hybrid method achieves the greatest conductivity in all isomeric CSCPs over conventional doping or cleavage techniques. The doped and side chain cleaved POET-T2-COOH displays a stable conductivity in inert atmospheres and a high work function of 5.3 eV, opening up new applications.

Bottom Electrode Modification Enables Efficient and Bright Silicon-Based Top-Emission Perovskite Light-Emitting Diodes.

The integration of perovskites with mature silicon platform has emerged as a promising approach in the development of efficient on-chip light sources and high-brightness displays. However, the performance of Si-based green perovskite light-emitting diodes (PeLEDs) still falls significantly short compared to their red and near-infrared counterparts. In this study, it is revealed that the high work function Au, widely employed in Si-based top-emission PeLEDs as the reflective bottom electrode, exhibits considerably lower reflectivity in the green spectrum than in the longer wavelengths. Consequently, Ag electrode is introduced to replace Au to enhance the green light reflectivity, and the ultrathin MoO3 and self-assembled monolayers (SAMs) are sequentially deposited for surface modification. These results indicate that the MoO3 layer removes the energy barrier at Ag/polymer hole transport layer interface, enhancing the hole injection efficiency; while the SAMs firmly anchor onto the MoO3 layer, effectively preventing interfacial defect formation. Benefited from this organic/inorganic dual-layer modification strategy, Si-based green PeLEDs with an impressive peak external quantum efficiency of 18.2% and a maximum brightness of 81931 cd m-2 are successfully fabricated, on par with those of the red and near-infrared counterparts. This achievement marks an advancement in developing high-performance Si-based PeLEDs with full-spectrum output.

Engineering of Interface Barrier in Hybrid MXene/GaN Heterostructures for Schottky Diode Applications.

The Fermi level position at the interface of a heterostructure is a critical factor for device functionality, strongly influenced by surface-related phenomena. In this study, contactless electroreflectance (CER) was utilized for the first time to investigate the built-in electric field in MXene/GaN structures with the goal of understanding the carrier transfer across the MXene/GaN interface. Five MXenes with high work functions were examined: Cr2C, Mo2C, V2C, V4C3, and Ti3C2. The physicochemical properties of the MXene/GaN structures were analyzed by using X-ray and UV photoelectron spectroscopies. It was shown that upon the coverage of the GaN surface by all investigated MXenes, a shift in the position of the surface Fermi level occurs, consequently raising the interface barrier. Additionally, the physicochemical stability of MXenes on the GaN surface was studied after annealing the structures at 750 °C. Our findings indicate that the annealing process increases the barrier height and the ionization energies of all studied structures. Furthermore, it has been shown that removing excess MXene material from the surface did not significantly impact the built-in electric field, emphasizing the robust physicochemical stability of the MXenes on the GaN surface. To validate the potential of engineering of MXene/GaN interface barrier, Schottky diodes with MXenes exhibiting the highest barrier height (Mo2C and V2C) were demonstrated.

A novel approach to enhancing performance and endurance in GeS2 OTS devices using amorphous carbon doped W2N electrodes

Three–dimensional (3D) cross-point (X–point) memory has gathered interest for its fast data processing and high density, achieved by stacking memory with a selector device to prevent misinterpretation. Ovonic threshold switching (OTS) is a promising selector due to its reversible switching behavior. Although, OTS devices typically employ transition metal nitrides (TMN) such as TiNx, TaNx, and WNx for electrodes owing to their good stability, high melting points, and low resistivity, TMNs can diffuse and degrade device performance by recrystallizing with chalcogenide alloys. Amorphous carbon (a–C) can be a good alternative electrode material due to its low roughness, cost–effectiveness, high work function (WF), and excellent thermal stability. However, the high resistivity of a–C (∼ 150 mΩ–cm) increases threshold voltage (Vth), causing high power consumption. Therefore, combining both a–C and TMN materials can effectively obtain their advantages. This study explores the effect of varying a–C content in W2N electrodes on GeS2–based OTS selectors. The (W2N)1-xCx (0 ≤ x ≤ 0.25) electrodes were deposited using DC magnetron co–sputtering. The phase of (W2N)1-xCx (0 ≤ x ≤ 0.25) films transformed from polycrystalline to amorphous with increasing x. Devices with (W2N)1-xCx/GeS2/W2N structure showed decreased Vth and off current, improving from 4.8 to 3.8 V and 8.0–4.17 nA, respectively. The subthreshold slope, distance between traps, and interface trap density (Nit) were extracted using the Pool–Frenkel model. The reduced Vth may be attributed to a higher WF and lower Nit with increasing x. The device’s lifetime improved up to 1.0 × 109 pulses for the highest a–C content in (W2N)1-xCx (0 ≤ x ≤ 0.25) electrodes.

Synergistic promotion of reaction kinetics for LiPSs at high loadings by interfacial built-in electric field and sulfur vacancies of ternary heterostructure for high-performance Li-S batteries

The practical application of lithium-sulfur batteries is significantly impeded by the chaotic migration of lithium polysulfides, sluggish redox-reaction kinetics, and pronounced shuttle effect. Herein, a ternary heterostructure (MoS2-x/MoO2/CoP) is developed with a spontaneous built-in electric field (BIEF) and enriched sulfur vacancies. This heterostructure comprises MoS2-x, which has a high adsorption capability and work function; CoP, noted for its low work function and potent catalytic properties; and MoO2, which features a work function between that of MoS2-x and CoP and serves as a bridge with excellent electronic conductivity. An appropriate combination of the catalyst and adsorbent with sulfur vacancies controls the direction of the BIEF, realizing the “adsorption-directed migration-catalytic” reaction mechanism for sulfur species. Specifically, the synergetic effect of the BIEF and sulfur vacancies enhances electron migration from CoP to MoS2-x, which improves the lithium polysulfide (LiPSs) trapping and accelerates the directional migration of LiPSs to CoP, thereby enabling the efficient catalytic conversion of sulfur species. Consequently, batteries equipped with MoS2-x/MoO2/CoP interlayers that contain sulfur vacancies demonstrate an ultrahigh initial specific capacity of 1356.2 mA h g−1 at 0.2 C, maintaining a capacity of 708.3 mAh g−1 after 1000 cycles at 2 C. Even with sulfur loading increased to 7.13 mg cm−2, these batteries display an initial specific capacity of 7.2 mAh cm−2. This work provides a feasible approach for the rational design of vacancy-containing ternary heterostructure catalysts for commercial lithium-sulfur batteries.

Enhanced Oxidation Resistance and Interface Stability of Atomic-Layer-Deposited MoNx Electrodes via TiN Passivation for DRAM Cell Capacitor Applications.

The continuous miniaturization of dynamic random-access memory (DRAM) capacitors has amplified the demand for electrode materials featuring specific characteristics, such as low resistivity, high work function, chemical stability, excellent interface quality with high-k dielectrics, and superior mechanical properties. In this study, molybdenum nitride (MoNx) films were deposited using a plasma-enhanced atomic layer deposition (PEALD) employing bis(isopropylcyclopentadienyl)molybdenum(IV) dihydride and NH3 plasma for DRAM capacitor electrode applications. Depending on the deposition temperatures of the PEALD MoNx films ranging from 200 to 400 °C, the Mo/N ratio and crystal structure varied, transitioning from the cubic NaCl-B1-type MoN phase with Mo/N ratio of 1.4 to the cubic γ-Mo2N phase with Mo/N ratio of 1.9. Notably, MoNx films grown at 400 °C exhibited low resistivity (435 μΩ·cm), a high work function (5.28 eV), and superior mechanical hardness (11.3 GPa) compared to ALD TiN films. Despite these excellent properties, the PEALD MoNx electrode demonstrated insufficient chemical stability, particularly in terms of oxidation resistance and interface quality with ALD HfxZr1-xO2 (HZO) films. This resulted in poor morphology and the formation of significant oxygen-deficient HZO layers (such as HfO2-x), leading to considerable degradation in the electrical performance of metal-insulator-metal (MIM) capacitors. To mitigate this issue, a thin (2.5-14 nm) ALD TiN layer was introduced as a passivation layer between the MoNx bottom electrode and HZO dielectric. The TiN-passivated MoNx (TiN/MoNx) electrode showed substantially enhanced oxidation resistance and reduced interfacial reactions with the HZO dielectric. Consequently, MIM capacitors with TiN/MoNx bottom electrodes demonstrated outstanding electrical performance, including excellent dielectric properties, low leakage current density, and high mechanical strength. Hence, this study proposes a promising candidates for storage nodes in the next-generation DRAM capacitors.

Achieving High Doping Density in pH-neutral Conjugated Polyelectrolyte Toward Effective Hole-Transporting Materials for Organic Solar Cells.

The lack of effective and non-corrosive hole-transporting layer (HTL) materials has remained a long-standing issue that severely restricts the performance of organic solar cells (OSCs). Most pH-neutral conjugated polyelectrolytes (CPEs) exhibit inferior performance to the acid-doped HTL materials due to their low doping density. In this study, a series of pH-neutral CPEs is designed and synthesized with high doping density as HTL materials. Through an elaborate synthetic route, two sulfonate-terminating alkoxyl side chains can be introduced into thiophene, by which the electron-rich, highly soluble, and chemically stable thiophene monomer is synthesized to enable the subsequent polymerization. The CPE PTT-F exhibit a remarkable self-doping property with an enhanced doping density from 2.01 × 1017 to 7.02 × 1018 cm-3. The high work function and the increased doping density of PTT-F-based HTL decrease the depletion region width from 38.4 to 8.1nm at the anode interface, which minimized the energy loss in hole transport. Consequently, a binary OSC modified by PTT-F-based HTL achieve a high PCE of 18.8%. To the best of the knowledge, this is the highest PCE for OSC employing CPE-based HTL. The results from this work demonstrate an encouraging achievement of realizing exceptional hole collection ability in pH-neutral CPEs.

Dressing AgNWs with MXenes Nanosheets: Transparent Printed Electrodes Combining High-Conductivity and Tunable Work Function for High-Performance Opto-Electronics.

High-work function transparent electrodes (HWFTEs) are key for establishing Schottky and Ohmic contacts with n-type and p-type semiconductors, respectively. However, the development of printable materials that combine high transmittance, low sheet resistance, and tunable work function remains an outstanding challenge. This work reports a high-performance HWFTE composed of Ag nanowires enveloped conformally by Ti3C2Tx nanosheets (TA), forming a shell-core network structure. The printed TA HWFTEs display an ultrahigh transmittance (>94%) from the deep-ultraviolet (DUV) to the entire visible spectral region, a low sheet resistance (<15 Ωsq-1), and a tunable work function ranging from 4.7 to 6.0eV. The introduction of additional oxygen terminations on the Ti3C2Tx surface generates positive dipoles, which not only increases the work function of the TA HWFTEs but also elevates the TA/Ga2O3 Schottky barrier, resulting in a high self-powered responsivity of 18mAW-1 in Ga2O3 diode DUV photodetectors, as demonstrated via experimental characterizations and theoretical calculations. Furthermore, the TA HWFTEs-based organic light-emitting transistors exhibit exceptional emission brightness of 5020cd m-2, being four-fold greater than that in Au electrodes-based devices. The innovative nano-structure design, work function tuning, and the revealed mechanisms of electrode-semiconductor contact physics constitute a substantial advancement in high-performance optoelectronic technology.

Unprecedented Hole Concentration of NiSe2 Electrodes Leading to Hole Degeneration of Entire WSe2 Channels.

Semimetal electrodes for 2D semiconductors have been extensively studied; however, research on p-type semimetals has been limited due to the scarcity of materials that satisfy both high work functions and low resistances. In response, we investigated the behavior of NiSe2 as an electrode. Utilizing a novel co-evaporation method that suppresses oxidation and contamination, we synthesized NiSe2 demonstrating a high work function of 5.53 eV, a low resistance of 5.81 × 10-5 Ω cm, and a record hole concentration exceeding 1023 cm-3. We confirmed that when WSe2 comes into contact with NiSe2, the Fermi level of WSe2 falls below the work function of NiSe2, leading to complete hole degeneration of the channel. This unusual Fermi level alignment correlates with the high hole concentration in NiSe2 and the maximum energy level of its hole pockets. Our research provides new insights into how an electrode's hole concentration affects channel behavior.

Experimental Verification of Inter Relation between Fowler–Nordheim and Millikan–Lauritsen Plot in Chemically Synthesized Zinc Oxide System

AbstractCold cathode emission or cold field emission (CFE) is a purely quantum mechanical phenomenon and a phenomenon of wonder. The exact science behind the observed current (I)–voltage (V) is yet to be pin pointed. For instance, a good cold emitter is very reasonably supposed to have low work function and good conductivity whereas a carbon allotropes like diamonds have just the reverse in both the cases, i.e., it is insulating in nature having very wide band gap as well as high work function yet it is considered to be an efficient field emitter. Since early of 20th century, till its middle a number of groups have suggested different equations or relations that can adequately describe the experimental CFE I–V characteristics adequately. Although they all fundamentally follow an exponential law, but so far, the relation suggests by Fowler and Nordheim (F–N) is the most accepted one. However, there is another relationship suggested by Millikan and Lauritsen (M–L) which is in spite of being reasonable not so common now a day to use. This work revisits different popular approaches for analyzing cold emission data. With this aim, the experimental CFE data obtained for chemically synthesized zinc oxide nanorods are chosen. The proper phase formation of ZnO is confirmed by XRD study whereas FESEM shows the rod like morphology. EDX confirms the proper stoichiometric ratio for the sample. After detail analysis it is confirmed that the theoretically proposed relation between F–N and M–L experimentally holds good as well and thus it would not be wrong to analyze the CFE data by simple M–L theory.

Magnetic Nanocomposite Modified Hybrid Hole-Transport Layer for Constructing Organic Solar Cells with High Efficiencies.

An interface modification layer holds paramount significance in reducing interface carrier recombination and improving the ohmic contact between the active layer and the electrode in organic solar cells (OSCs). Modifying or doping the widely used hole-transport layer (HTL) PEDOT:PSS to adjust the work function, conductivity, and acidity has become a common strategy for achieving high-performance OSCs. Metal oxides and two-dimensional materials as secondary dopants into PEDOT:PSS, respectively, as well as a replacement of PEDOT:PSS both exhibit immense potential for achieving high-performance OSCs due to their excellent electrical properties. Herein, we report a method utilizing a Fe3O4/GO magnetic nanocomposite as a secondary dopant for PEDOT:PSS to modulate its inherent properties for constructing high-efficiency OSCs. The magnetic nanocomposite hybrid HTL exhibits a suitable optical transmittance and higher work function. Meanwhile, it is found that the addition of Fe3O4/GO magnetic nanoparticles expands the domain of PEDOT and enhances the phase separation between PEDOT and PSS segments, thereby improving the conductivity of PEDOT:PSS. By fine-tuning the doping ratio of a Fe3O4/GO magnetic nanocomposite in PEDOT:PSS, the best power conversion efficiency of OSCs based on PM6:L8-BO was up to 18.91%. The notable enhancement of the device's performance was due to the enhanced hole mobility and the improved charge extraction, further complemented by the decreased likelihood of interface recombination brought about by the hybrid HTL. Compared with PEDOT:PSS-based OSCs, an enhanced stability of the hybrid HTL-based device was also obtained. In addition, the diverse adaptability of the hybrid HTL was demonstrated in enhancing the performance of OSCs that are based on PM6:Y6 and PBDB-T:ITIC. The effectiveness and versatility of a magnetic nanocomposite hybrid HTL present opportunities for achieving high-performance OSCs.