Interfacial Buffer Layer Research Articles

Impact of graded CIGS absorber layer on Cd-free CIGS thin-film solar cell performance: numerical optimization

Abstract This paper investigates replacing the CdS buffer layer with (Zn, Mg)O and Zn(S, O) double buffer layers. To increase the efficiency of the structure, our strategy involves numerically studying and comparing three types of CIGS bandgap absorber layers: FB (Flat Band), Double Gradient Bandgap (DG) with a high bandgap near the Mo contact (back side), a low bandgap near the buffer layer (front side), and a minimum bandgap between them, and Simple Gradient Bandgap (SG) with a high bandgap near the Mo contact (back side) and a low bandgap near the buffer layer (front side). Each type features different linear graded profiles in the thickness direction to determine the optimal bandgap gradient of the CIGS layer. The performance of the three types is numerically analyzed using the SCAPS-1D simulator. Simulation enables us to test multiple structural combinations efficiently, saving both time and money, while providing results that guide experimental research. The proposed device structure is composed of the following layers: ZnO:Al/n-Zn1-xMgxO/n- ZnSxO1-x/p- Graded-CuIn1-xGaxSe2 /Mo. To study the effects of linear bandgap gradient distribution of Ga⁄((Ga+In) ) ratio according to the thickness direction on CIGS solar cell performance, the electrical properties of the proposed CIGS model were initially matched with experimental data to confirm the structure's accuracy. It was found that the Double Gradient Bandgap (DG), with maxima of 1.44 eV at the back side (near Mo contact), 1.238 eV at the front side (near n-type buffer layer interface), and a minimum of 1.154 eV at a position of 1.7 µm from the back side, has a higher efficiency than the other structures with 26.22% (Voc = 0.8134 V, Jsc = 37.82 mA/cm², FF = 85.21%). Optimizing the bandgap gradient of the CIGS absorber layer helps improve the efficiency of CIGS solar cells. 

Optoelectronic properties of electron-acceptor molecules adsorbed on graphene/silicon carbide interfaces

Silicon carbide has emerged as an optimal semiconducting support for graphene growth. In previous studies, the formation of an interfacial graphene-like buffer layer covalently bonded to silicon carbide has been observed, revealing electronic properties distinct from ideal graphene. Despite extensive experimental efforts dedicated to this interface, theoretical investigations have been confined to its ground state. Here, we use many-body perturbation theory to study the electronic and optical characteristics of this interface and demonstrate its potential for optoelectronics. By adsorbing graphene, we show that the quasiparticle band structure exhibits a reduced bandgap, associated with an optical onset in the visible energy window. Furthermore, we reveal that the absorption of two prototypical electron-accepting molecules on this substrate results in a significant renormalization of the adsorbate gap, giving rise to distinct low-lying optically excited states in the near-infrared region. These states are well-separated from the substrate’s absorption bands, ensuring wavelength selectivity for molecular optoelectronic applications.

Dual-Band Photomultiplication-Type Organic Photodetectors with Ultrahigh Signal-to-Noise Ratios.

A series of dual-band photomultiplication (PM)-type organic photodetectors (OPDs) were fabricated by employing a donor(s)/acceptor (100:1, wt/wt) mixed layer and an ultrathin Y6 layer as the active layers, as well as by using PNDIT-F3N as an interfacial layer near the indium tin oxide (ITO) electrode. The dual-band PM-type OPDs exhibit the response range of 330-650 nm under forward bias and the response range of 650-850 nm under reverse bias. The tunable spectral response range of dual-band PM-type OPDs under forward or reverse bias can be explained well from the trapped electron distribution near the electrodes. The dark current density (JD) of the dual-band PM-type OPDs can be efficiently suppressed by employing PNDIT-F3N as the anode interfacial layer and the special active layers with hole-only transport characteristics. The light current density (JL) of the dual-band PM-type OPDs can be slightly increased by incorporating wide-bandgap polymer P-TPDs with relatively large hole mobility (μh) in the active layers. The signal-to-noise ratios of the optimized dual-band PM-type OPDs reach 100,980 under -50 V bias and white light illumination with an intensity of 1.0 mW·cm-2, benefiting from the ultralow JD by employing wide-bandgap PNDIT-F3N as the anode interfacial buffer layer and the increased JL by incorporating appropriate P-TPD in the active layers.

In-situ constructed interface buffer layer enabled highly reversible Zn Deposition/Stripping for long-lifespan aqueous zinc metal anodes

Despite the advantages of high capacity, high safety and low cost, zinc anodes also face the inherent problems of dendritic growth, corrosion and passivation, vastly limiting the development and application of aqueous zinc ion batteries (AZIBs). Here, the epigallocatechin gallate (EGCG) was used as a hydroxyl-rich natural electrolyte additive for AZIBs. During charge–discharge process, the EGCG can be preferentially adsorbed on the zinc anode, and act as an interface buffer layer to weaken the direct contact between active water molecule and zinc anode. Based on this effect, the interface buffer layer is helped to inhibit the water-induced side reactions of hydrogen evolution, zinc corrosion and passivation, and lower the polarization overpotential, contributing to highly reversible Zn deposition/stripping behavior. As a result, the Zn||Zn symmetric batteries can maintain a stable cycling for more than 1500 h at 1.0 mA cm−2 and 1.0 mAh cm−2. Furthermore, the assembled Zn||MnO2 full batteries still delivered high capacity retention of 98.02 % after 400 cycles at 1.0 A/g. This finding enriches the design thoughts for the development of high-efficiency and practical AZIBs.

Enhanced dielectric properties induced by the rational design of interfacial buffer layer in MoS2/poly(arylene ether nitrile) composites

Enhanced dielectric properties induced by the rational design of interfacial buffer layer in MoS2/poly(arylene ether nitrile) composites

Dendrite-free deposition and side-reaction suppression of zinc anodes achieved via constructing synergistic interface buffer layers

Constructing a bifunctional buffer layer for the zinc anode (δ-MnO2@Zn) effectively adsorbs Zn2+ and reduces the bound water in Zn2+ solvent shell for uniform Zn deposition. The symmetric cell achieving a long cycle life of over 890 h at 1 mA cm−2.

Multifunctional and multi-site interfacial buffer layer for efficient and stable perovskite solar cells

Perovskite solar cells (PSCs) have achieved significant success in power conversion efficiency (PCE) and stability. However, interfacial recombination and film defects still hinder the improvement of PSCs efficiency. In this study, we propose a novel interfacial buffer layer material called Ethyl p-nitrobenzoate (EPN) to enhance device performance and stability. Our results demonstrate that introducing EPN improves the film's quality, reduces defect density, relieves interfacial stress, and significantly suppresses nonradiative recombination at the interface. Density functional theory (DFT) calculations confirm that EPN can effectively passivate defects in the perovskite and SnO2 films due to its multifunctionality. Finally, we achieved a high PCE of 23.16% for the target device while significantly enhancing device stability compared to the control. This work provides new insights into the development of multifunctional multi-site interfacial buffer layers for high-performance PSCs.

Bulk Contact Between Silver Nanowires Top Electrode and Interface Layer Enables High Performance of Full‐Solution‐Processed Semitransparent Organic Solar Cell Module

The solution‐processed electrode is key to the full‐solution‐processed organic solar cells (OSCs). Silver nanowires (AgNWs) are considered as an attractive solution‐processed electrode due to their low sheet resistance and high transmittance. However, the traditional “line‐plane” contact between AgNWs and the interface buffer layer is insufficient, resulting in the low performance of full‐solution‐processed OSCs. Herein, a bulk contact structure is reported between AgNWs and interface, formed by inserting the interface layer material, such as HMoOx (hydrogen molybdenum bronze) into the AgNWs networks. The extra HMoOx can be connected with the bottom interface buffer layer, forming a longitudinal network, and wrapping the AgNWs in the longitudinal interfacial layer. This bulk contact electrode‐interface structure increases the area of AgNWs/interface layers, promoting charge transfer and collection. Besides, the top‐injected method can enable the formation of a water‐based ink film on the top of the organic layer, as well as avoid solvent erosion between AgNWs and the interface layer. Based on the bulk contact electrode‐interface structure, this work realized high performance of 12.27% and 9.54% for 0.09 cm2 small‐area device and 10.8 cm2 full‐solution‐processed semitransparent mini‐module. These results provide a new idea for full‐solution‐processed OSCs preparation.

Improving Perovskite Green Quantum Dot Light-Emitting Diode Performance by Hole Interface Buffer Layers.

Perovskite quantum dot light-emitting diodes (QLEDs) are potential candidates for next-generation displays due to their high color purity and wide color gamut. Due to the strong electron-accepting ability of poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), quantum dot (QD) films are prone to be charged, which leads to the imbalance of charge injection and the increase of nonradiative recombination, ultimately affecting the performance of the QLEDs. Here, we compared and studied two polymers, poly(methyl methacrylate) (PMMA) and poly(vinyl pyrrolidone) (PVP), as the hole interface buffer layers of QD films, which effectively reduced the defect density, suppressed nonradiative recombination, and greatly improved the efficiency and stability of QLEDs. The devices with PMMA achieved a maximum external quantum efficiency of 20.71%.

Alumina Nanoparticle Interfacial Buffer Layer for Low‐Bandgap Lead‐Tin Perovskite Solar Cells

AbstractMixed lead‐tin (Pb:Sn) halide perovskites are promising absorbers with narrow‐bandgaps (1.25–1.4 eV) suitable for high‐efficiency all‐perovskite tandem solar cells. However, solution processing of optimally thick Pb:Sn perovskite films is notoriously difficult in comparison with their neat‐Pb counterparts. This is partly due to the rapid crystallization of Sn‐based perovskites, resulting in films that have a high degree of roughness. Rougher films are harder to coat conformally with subsequent layers using solution‐based processing techniques leading to contact between the absorber and the top metal electrode in completed devices, resulting in a loss of VOC, fill factor, efficiency, and stability. Herein, this study employs a non‐continuous layer of alumina nanoparticles distributed on the surface of rough Pb:Sn perovskite films. Using this approach, the conformality of the subsequent electron‐transport layer, which is only tens of nanometres in thickness is improved. The overall maximum‐power‐point‐tracked efficiency improves by 65% and the steady‐state VOC improves by 28%. Application of the alumina nanoparticles as an interfacial buffer layer also results in highly reproducible Pb:Sn solar cell devices while simultaneously improving device stability at 65 °C under full spectrum simulated solar irradiance. Aged devices show a six‐fold improvement in stability over pristine Pb:Sn devices, increasing their lifetime to 120 h.

Sn and Ge Complexes with Redox-Active Ligands as Efficient Interfacial Membrane-like Buffer Layers for p-i-n Perovskite Solar Cells

Inverted perovskite solar cells with a p-i-n configuration have attracted considerable attention from the research community because of their simple design, insignificant hysteresis, improved operational stability, and low-temperature fabrication technology. However, this type of device is still lagging behind the classical n-i-p perovskite solar cells in terms of its power conversion efficiency. The performance of p-i-n perovskite solar cells can be increased using appropriate charge transport and buffer interlayers inserted between the main electron transport layer and top metal electrode. In this study, we addressed this challenge by designing a series of tin and germanium coordination complexes with redox-active ligands as promising interlayers for perovskite solar cells. The obtained compounds were characterized by X-ray single-crystal diffraction and/or NMR spectroscopy, and their optical and electrochemical properties were thoroughly studied. The efficiency of perovskite solar cells was improved from a reference value of 16.4% to 18.0-18.6%, using optimized interlayers of the tin complexes with salicylimine (1) or 2,3-dihydroxynaphthalene (2) ligands, and the germanium complex with the 2,3-dihydroxyphenazine ligand (4). The IR s-SNOM mapping revealed that the best-performing interlayers form uniform and pinhole-free coatings atop the PC61BM electron-transport layer, which improves the charge extraction to the top metal electrode. The obtained results feature the potential of using tin and germanium complexes as prospective materials for improving the performance of perovskite solar cells.

In-situ cross-linked multifunctional polymer electrolyte buffer layers for high-performance garnet solid-state lithium metal batteries

The garnet Li6.75La3Zr1.75Ta0.25O12 (LLZTO) is one of the most promising electrolytes for commercial application since of its high ionic conductivity and good stability to Li. Nevertheless, the poor electrolyte/electrode interface contact enlarges the interface impedance of all-solid-state battery (ASSB). Herein, a multifunctional polymer electrolyte (MPE) interface buffer layers are formed on both sides of LLZTO surface through an in-situ crosslinking strategy to improve the interface contact with electrodes, which can facilitate uniform Li+ deposition/exfoliation and inhibit the growth of lithium dendrites as evidenced by the reduced interface impedance (103.4 Ω cm2), the increased critical current density (CDD, 1.2 mA cm−2) and 950 h stable cycle of Li symmetric cells at 0.7 mA cm−2, 0.7 mA h cm−2. Besides, the MPE layer can reduce the magnitude of electric field at the interface and widen the electrochemical window (0∼5.2 V). The stable interface of the LLZTO@MPE/cathode enables the full cells matching with the LiFePO4 (LFP) and LiNi0.5Co0.2Mn0.3O2 (NCM523) cathodes to deliver superior electrochemical performances. Specifically, the Li/MPE@LLZTO@MPE/LFP delivers a capacity retention rate of 87% after 200 cycles at 1 C. When it’s matched with the NCM523 cathode, a capacity retention rate of 98% is retained after 100 cycles at 1 C. This work provides an effective and simple way to build good-interface-contact and long-lifespan garnet solid-state lithium metal batteries (SSLMBs).

Effect of Residual Carbon on Spin‐Polarized Coupling at a Graphene/Ferromagnet Interface

AbstractVertical stacks of graphene and ferromagnetic layers are predicted to be efficient spin filters, while the experimentally observed figures of merit systematically remain below the theoretical predictions. According to general consensus, a vaguely defined interface contamination is found responsible for this discrepancy. Here, it is demonstrated how the spin‐polarized electronic structure of single‐layer graphene supported on a ferromagnetic cobalt substrate is affected by the presence of an interfacial carbidic buffer layer, formed by residual carbon present in the Co substrate. It is found that the Co‐C hybridized single‐spin state near the Fermi level disappears upon thermal segregation of bulk carbon at the graphene–Co interface, which determines the electronic decoupling of graphene from the ferromagnetic support and consequently, the suppression of net spin polarization. These observations are shown to be independent of the graphene azimuthal orientation with respect to the high symmetry directions of the substrate. The findings provide clear evidence that the realization of highly polarized spin currents in graphene/ferromagnet heterostacks depends on careful control of the graphene growth process in order to eliminate interfacial carbon.

Effect of EVA-TiO2 composite interfacial buffer layer in improving the bond strength between PMMA denture base and PDMS liner

Polydimethylsiloxane (PDMS) is the most common dental liner that is used with acrylic dentures. A strong bond between the liner and the denture is a must, for the proper functioning and the longevity of the prosthesis. Debonding of the liner may occur due to an inefficient bond with the denture, or low cohesive strength due to wettablility/hydration and water/liquid storage-retention. The increased wettability/hydration pass on the moisture to the acrylic boundary surface causing initiation of debonding process. Hence, in order to prevent the debonding due to wettablility/hydration a novel method of introducing a hydrophobic polymer interfacial buffer layer between the acrylic denture surface and the PDMS liner surface is suggested. In, the present research work, ethylene vinylacetate (EVA) reinforced with titania (TiO2) polymer microfilm composite layer is prepared by solution casting method. The thin polymer film is placed between the acrylic denture surface and the PDMS liner surface and heat cured together to obtain a hydrophobic interfacial buffer layer. Wettability, fluid absorption and retention tests were performed to investigate the hydrophobic properties of the composite interfacial buffer layer. Mechanical strength properties on the prepared specimen (as per ISO 178) revealed that the EVA-TiO2 layer offered superior bonding and also improved the overall mechanical properties of the acrylic dentures without disturbing the mass and density of the denture.

High-performance solid-state lithium metal batteries achieved by interface modification

Garnet-structured ceramic electrolyte Li6.75La3Zr1.75Ta0.25O12 (LLZTO) attracts significant consideration in solid-state Li metal batteries due to its wide electrochemical window and favorable compatibility with Li metal. However, the deployment of LLZTO is severely hampered by poor contact between LLZTO and Li metal anode. In this paper, an ultra-thin Al-Si interface buffer layer (10 nm) is constructed on LLZTO by a magnetron sputtering method, which allows superior wetting of Li onto the LLZTO surface due to the alloying reaction between the Al-Si layer and Li metal. The resulting Li/Al-Si coated LLZTO (ASL)/Li symmetrical cell delivers an interfacial resistance of 15.0 Ω cm−2, which is much lower than that of 1140.3 Ω cm−2 for the bare LLZTO symmetrical cell. Moreover, the Li/ASL/Li symmetrical cells exhibit stable plating/striping performance (800 h) with small voltage hysteresis at 1.0 mA cm−2. Besides, the full cell with LiFePO4 cathode reveals a high capacity of 124.1 mA h g−1 after 600 cycles at 0.5C with a low-capacity decay of 0.032% per cycle. We believe this work will facilitate the development of solid-state rechargeable batteries.

Recent Advances in g-C3N4 for the Application of Perovskite Solar Cells.

In this study, graphitic carbon nitride (g-C3N4) was extensively utilized as an electron transport layer or interfacial buffer layer for simultaneously realizing photoelectric performance and stability improvement of perovskite solar cells (PSCs). This review covers the different g-C3N4 nanostructures used as additive and surface modifier layers applied to PSCs. In addition, the mechanism of reducing the defect state in PSCs, including improving the crystalline quality of perovskite, passivating the grain boundaries, and tuning the energy level alignment, were also highlighted in this review. Currently, the power conversion efficiency of PSCs based on modified g-C3N4 has been increased up to 22.13%, and its unique two-dimensional (2D) package structure has enhanced the stability of PSCs, which can remain stable in the dark for over 1500 h. Finally, the potential challenges and perspectives of g-C3N4 incorporated into perovskite-based optoelectronic devices are also included in this review.

An inverted architecture P3HT:CdSe bulk-heterojunction hybrid solar cell utilizing a quantum junction with high open circuit voltage and efficiency

Exploring CdSe QDs as a substitute for [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) in Poly (3-hexylthiophene) (P3HT) based photovoltaic devices received much attention due to its properties such as tunable band gap over the visible range, better band alignment with P3HT and inexpensiveness. But, the VOC values of the P3HT:CdSe QDs bulk-heterojunction (BHJ) hybrid solar cells are still inferior, which happens to be the main performance-limiting factor for these devices. We have resolved this issue in this study by the application of an interfacial buffer layer (BL) in an inverted architecture utilizing zinc oxide (ZnO) as an electron transporting layer. The BL was also formed of CdSe QDs. It was found that the application of the interfacial BL reduces the interface recombination which resulted in a VOC value of 0.96 V. To the best of our knowledge, this is the best VOC value reported for the P3HT:CdSe QDs BHJ system so far. A quantum junction (QJ) was also formed between the QDs in the BL and the QDs in the BHJ by passivating them with Iodine and 3-Mercaptopropionic acid (MPA), respectively. The QJ induces an extended electric field in the BHJ which benefits charge extraction and ultimately resulting in an enhanced short circuit current (JSC).

(Digital Presentation) Ultrathin Stabilized Zn Metal Anode for Highly Reversible Aqueous Zn-Ion Batteries

Ever-increasing demands for energy, particularly being environmentally friendly have promoted the transition from fossil fuels to renewable energy.1 Lithium-ion batteries (LIBs), arguably the most well-studied energy storage system, have dominated the energy market since their advent in the 1990s.2 However, challenging issues regarding safety, supply of lithium, and high price of lithium resources limit the further advancement of LIBs for large-scale energy storage applications.3 Therefore, attention is being concentrated on an alternative electrochemical energy storage device that features high safety, low cost, and long cycle life. Rechargeable aqueous zinc-ion batteries (ZIBs) is considered one of the most promising alternative energy storage systems due to the high theoretical energy and power densities where the multiple electrons (Zn2+) . In addition, aqueous ZIBs are safer due to non-flammable electrolyte (e.g., typically aqueous solution) and can be manufactured since they can be assembled in ambient air conditions. 4 As an essential component in aqueous Zn-based batteries, the Zn metal anode generally suffers from the growth of dendrites, which would affect battery performance in several ways. Second, the led by the loose structure of Zn dendrite may reduce the coulombic efficiency and shorten the battery lifespan.5 Several approaches were suggested to improve the electrochemical stability of ZIBs, such as implementing an interfacial buffer layer that separates the active Zn from the bulk electrolyte.6 However, the and thick thickness of the conventional Zn metal foils remain a critical challenge in this field, which may diminish the energy density of the battery drastically. According to a theretical calculation, the thickness of a Zn metal anode with an areal capacity of 1 mAh cm-2 is about 1.7 μm. However, existing extrusion-based fabrication technologies are not capable of downscaling the thickness Zn metal foils below 20 μm.Herein, we demonstrate a thickness controllable coating approach to fabricate an ultrathin Zn metal anode as well as a thin dielectric oxide separator. First, a 1.7 μm Zn layer was uniformly thermally evaporated onto a Cu foil. Then, Al2O3 , the separator was deposited through sputtering on the Zn layer to a thickness of 10 nm. The inert and high hardness Al2O3 layer is expected to lower the polarization and restrain the growth of Zn dendrites. Atomic force microscopy was employed to evaluate the roughness of the surface of the deposited Zn and Al2O3/Zn anode structures. Long-term cycling stability was gauged under the symmetrical cells at 0.5 mA cm-2 for 1 mAh cm-2. Then the fabricated Zn anode was paired with MnO2 as a full cell for further electrochemical performance testing. To investigate the evolution of the interface between the Zn anode and the electrolyte, a home-developed in-situ optical observation battery cage was employed to record and compare the process of Zn deposition on the anodes of the Al2O3/Zn (demonstrated in this study) and the procured thick Zn anode. The surface morphology of the two Zn anodes after circulation was characterized and compared through scanning electron microscopy. The tunable ultrathin Zn metal anode with enhanced anode stability provides a pathway for future high-energy-density Zn-ion batteries. Obama, B., The irreversible momentum of clean energy. Science 2017, 355 (6321), 126-129. Goodenough, J. B.; Park, K. S., The Li-ion rechargeable battery: a perspective. J Am Chem Soc 2013, 135 (4), 1167-76. Li, C.; Xie, X.; Liang, S.; Zhou, J., Issues and Future Perspective on Zinc Metal Anode for Rechargeable Aqueous Zinc‐ion Batteries. Energy & Environmental Materials 2020, 3 (2), 146-159. Jia, H.; Wang, Z.; Tawiah, B.; Wang, Y.; Chan, C.-Y.; Fei, B.; Pan, F., Recent advances in zinc anodes for high-performance aqueous Zn-ion batteries. Nano Energy 2020, 70. Yang, J.; Yin, B.; Sun, Y.; Pan, H.; Sun, W.; Jia, B.; Zhang, S.; Ma, T., Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives. Nanomicro Lett 2022, 14 (1), 42. Yang, Q.; Li, Q.; Liu, Z.; Wang, D.; Guo, Y.; Li, X.; Tang, Y.; Li, H.; Dong, B.; Zhi, C., Dendrites in Zn-Based Batteries. Adv Mater 2020, 32 (48), e2001854. AcknowledgmentThis work was partially supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 22011044) by KRISS. Figure 1

Analysis of different buffer layers on CuO based solar cells using SCAPS-1D

We have used SCAPS-1D to do simulations on CuO based solar cells using ZnO, TiO2, CdS and ZnSe as buffer layers. The solar cell characteristics are analysed by varying different material properties. The CuO/ZnO based solar cell showed highest efficiency ~20%. The interface defect however impacts the efficiency of this solar cell significantly. The interface defect and buffer layer thickness has shown little impact on the TiO2 and ZnSe buffer layer based solar cell. Further, we have optimized the impact of absorber layer thickness, carrier concentration and absorber defect as well. The effect of buffer layer thickness and electron affinity has also been investigated. Further, we have tried to understand the effect of temperature on the performance of these solar cells. The increase in temperature has resulted in decreased efficiency attributing to increased recombination rate.

Dimensionally stable anodes for the oxygen evolution reaction: Ruthenium dioxide on a nickel metal substrate

Dimensionally stable anodes (DSA) for the oxygen evolution reaction (OER) gradually passivate under operating conditions due to the formation of insulating TiO2 at the interface of the Ti-metal substrate and the catalytically active metal oxide layer (typically a mixture of ruthenium and iridium oxides). The incorporation of a catalytically active, yet stable, interfacial buffer layer or substrate is a potential means of promoting the overall performance. Here, we prepared DSA-like RuO2 on Ni films by the thermal decomposition method and contrast their OER activity with an analogous RuO2 on Ti-metal film. The fabrication process resulted in the presence of NiO and Ni oxides/(oxy)hydroxides at the surface of the rutile RuO2 layer. Along with RuO2, the former species were active in the water splitting reaction under the testing conditions. Ni–RuO2 films showed lower OER overpotentials relative to Ti–RuO2 suggesting a synergistic effect between Ni- and Ru-oxides and the Ni layer between Ti and RuO2 to improve overall performance. Further studies should optimize the NiO–RuO2 loading levels, understand the NiO–RuO2 synergy toward catalytic performance and determine the stability under accelerated testing conditions.