Now showing items 1-20 of 3267

    • Perovskite-Nanosheet Sensitizer for Highly Efficient Organic X-ray Imaging Scintillator

      Wang, Jian-Xin; Wang, Xiaojia; Yin, Jun; Gutierrez Arzaluz, Luis; He, Tengyue; Chen, Cailing; Han, Yu; Zhang, Yuhai; Bakr, Osman; Eddaoudi, Mohamed; Mohammed, Omar F. (ACS Energy Letters, American Chemical Society (ACS), 2021-11-27) [Article]
      The weak X-ray capture capability of organic scintillators always leads to poor imaging resolution and detection sensitivity. Here, we realize an efficient and reabsorption-free organic scintillator at the interface of perovskite nanosheets using a very efficient energy transfer strategy. Our steady-state and ultrafast time-resolved experiments supported by density functional theory calculations demonstrate that an efficient interfacial energy transfer from the perovskite nanosheet to the organic chromophore with thermally activated delayed fluorescence (TADF) character can be achieved. Interestingly, we found that the direct harnessing of both singlet and triplet excitons of the TADF chromophores also contributed greatly to its remarkably enhanced radioluminescence intensity and X-ray sensitivity. A high X-ray imaging resolution of 135 μm and a low detection limit of 38.7 nGy/s were achieved in the fabricated X-ray imaging scintillator.
    • Transistors based on two-dimensional materials for future integrated circuits

      Das, Saptarshi; Sebastian, Amritanand; Pop, Eric; McClellan, Connor J.; Franklin, Aaron D.; Grasser, Tibor; Knobloch, Theresia; Illarionov, Yury; Penumatcha, Ashish V.; Appenzeller, Joerg; Chen, Zhihong; Zhu, Wenjuan; Asselberghs, Inge; Li, Lain-Jong; Avci, Uygar E.; Bhat, Navakanta; Anthopoulos, Thomas D.; Singh, Rajendra (Nature Electronics, Springer Science and Business Media LLC, 2021-11-25) [Article]
      Field-effect transistors based on two-dimensional (2D) materials have the potential to be used in very large-scale integration (VLSI) technology, but whether they can be used at the front end of line or at the back end of line through monolithic or heterogeneous integration remains to be determined. To achieve this, multiple challenges must be overcome, including reducing the contact resistance, developing stable and controllable doping schemes, advancing mobility engineering and improving high-κ dielectric integration. The large-area growth of uniform 2D layers is also required to ensure low defect density, low device-to-device variation and clean interfaces. Here we review the development of 2D field-effect transistors for use in future VLSI technologies. We consider the key performance indicators for aggressively scaled 2D transistors and discuss how these should be extracted and reported. We also highlight potential applications of 2D transistors in conventional micro/nanoelectronics, neuromorphic computing, advanced sensing, data storage and future interconnect technologies.
    • The development of integrated circuits based on two-dimensional materials

      Zhu, Kaichen; Wen, Chao; Aljarb, Areej A.; Xue, Fei; Xu, Xiangming; Tung, Vincent; Zhang, Xixiang; Alshareef, Husam N.; Lanza, Mario (Nature Electronics, Springer Science and Business Media LLC, 2021-11-22) [Article]
      Two-dimensional (2D) materials could potentially be used to develop advanced monolithic integrated circuits. However, despite impressive demonstrations of single devices and simple circuits—in some cases with performance superior to those of silicon-based circuits—reports on the fabrication of integrated circuits using 2D materials are limited and the creation of large-scale circuits remains in its infancy. Here we examine the development of integrated circuits based on 2D layered materials. We assess the most advanced circuits fabricated so far and explore the key challenges that need to be addressed to deliver highly scaled circuits. We also propose a roadmap for the future development of integrated circuits based on 2D layered materials.
    • Activated Carbon from Palm Date Seeds for CO2 Capture

      Alazmi, Amira; Nicolae, Sabina A.; Modugno, Pierpaolo; Hasanov, Bashir E.; Titirici, Maria M.; Da Costa, Pedro M. F. J. (International Journal of Environmental Research and Public Health, MDPI AG, 2021-11-19) [Article]
      The process of carbon dioxide capture and storage is seen as a critical strategy to mitigate the so-called greenhouse effect and the planetary climate changes associated with it. In this study, we investigated the CO2 adsorption capacity of various microporous carbon materials originating from palm date seeds (PDS) using green chemistry synthesis. The PDS was used as a precursor for the hydrochar and activated carbon (AC). Typically, by using the hydrothermal carbonization (HTC) process, we obtained a powder that was then subjected to an activation step using KOH, H3PO4 or CO2, thereby producing the activated HTC-PDS samples. Beyond their morphological and textural characteristics, we investigated the chemical composition and lattice ordering. Most PDS-derived powders have a high surface area (>1000 m2 g−1) and large micropore volume (>0.5 cm3 g−1). However, the defining characteristic for the maximal CO2 uptake (5.44 mmol g−1, by one of the alkaline activated samples) was the lattice restructuring that occurred. This work highlights the need to conduct structural and elemental analysis of carbon powders used as gas adsorbents and activated with chemicals that can produce graphite intercalation compounds.
    • Doping Approaches for Organic Semiconductors

      Scaccabarozzi, Alberto D.; Basu, Aniruddha; Aniés, Filip; Liu, Jian; Zapata-Arteaga, Osnat; Warren, Ross; Firdaus, Yuliar; Nugraha, Mohamad Insan; Lin, Yuanbao; Campoy-Quiles, Mariano; Koch, Norbert; Müller, Christian; Tsetseris, Leonidas; Heeney, Martin; Anthopoulos, Thomas D. (Chemical Reviews, American Chemical Society (ACS), 2021-11-18) [Article]
      Electronic doping in organic materials has remained an elusive concept for several decades. It drew considerable attention in the early days in the quest for organic materials with high electrical conductivity, paving the way for the pioneering work on pristine organic semiconductors (OSCs) and their eventual use in a plethora of applications. Despite this early trend, however, recent strides in the field of organic electronics have been made hand in hand with the development and use of dopants to the point that are now ubiquitous. Here, we give an overview of all important advances in the area of doping of organic semiconductors and their applications. We first review the relevant literature with particular focus on the physical processes involved, discussing established mechanisms but also newly proposed theories. We then continue with a comprehensive summary of the most widely studied dopants to date, placing particular emphasis on the chemical strategies toward the synthesis of molecules with improved functionality. The processing routes toward doped organic films and the important doping–processing–nanostructure relationships, are also discussed. We conclude the review by highlighting how doping can enhance the operating characteristics of various organic devices.
    • Inherent Surface Activation of Laser-Scribed Graphene Decorated with Au and Ag Nanoparticles: Simultaneous Electrochemical Behavior toward Uric Acid and Dopamine

      Beduk, Tutku; De Oliveira Filho, José Ilton; Ait Lahcen, Abdellatif; Mani, Veerappan; Salama, Khaled N. (Langmuir, American Chemical Society (ACS), 2021-11-17) [Article]
      Laser-scribed graphene electrodes (LSGEs) have attracted great attention for the development of electrochemical (bio)sensors due to their excellent electronic properties, large surface area, and high porosity, which enhances the electrons’ transfer rate. An increasing active surface area and defect sites are the quickest way to amplify the electrochemical sensing attributes of the electrodes. Here, we have found that the activation procedure coupled to the electrodeposition of metal nanoparticles resulted in a significant amplification of the active area and the analytical performance. This preliminary study is supported by the demonstration of the simultaneous electrochemical sensing of dopamine (DA) and uric acid (UA) by the electrochemically activated LSGEs (LSGE*s). Furthermore, the electrodeposition of two different metal nanoparticles, gold (Au) and silver (Ag), was performed in multiple combinations on working and reference electrodes to investigate the enhancement in the electrochemical response of LSGE*s. Current enhancements of 32, 27, and 35% were observed from LSGE* with WE:Au/RE:LSG/CE:LSGE, WE:Au/RE:Au/CE:LSGE, and WE:Au/RE:Ag/CE:LSGE, compared to the same combinations of LSGEs without any surface activation. A homemade and practical potentiostat, KAUSTat, was used in these electrochemical depositions in this study. Among all of the combinations, the surface area was increased 1.6-, 2.0-, and 1.2-fold for WE:Au/RE:LSG/CE:LSGE, WE:Au/RE:Au/CE:LSGE, and WE:Au/RE:Ag/CE:LSGE prepared from LSGE*s, respectively. To evaluate the analytical performance, DA and UA were detected simultaneously in the presence of ascorbic acid. The LODs of DA and UA are calculated to be ∼0.8 and ∼0.6 μM, respectively. Hence, this study has the potential to open new insights into new surface activation strategies with a combination of one-step nanostructured metal depositions by a custom-made potentiostat. This novel strategy could be an excellent and straightforward method to enhance the electrochemical transducer sensitivity for various electrochemical sensing applications.
    • Rapid photodegradation of organic micro-pollutants in water using high-intensity pulsed light

      Fortunato, Luca; Yarali, Emre; Sanchez Huerta, Claudia; Anthopoulos, Thomas D. (Journal of Water Process Engineering, Elsevier BV, 2021-11-17) [Article]
      The rising concentration of organic micro-pollutants (OMPs) in water resources has become a major concern for aquatic ecosystems and human health. Advanced oxidation processes (AOPs), based on ultraviolet (UV) photolysis and photochemical reactions, have been suggested for the degradation of various micropollutants present in water and wastewater. However, the application of these methods on large scale is limited due to the long treatment times. Here we evaluate the efficiency of high-intensity pulsed light treatment (HIPL) for the degradation of organic compounds in aqueous conditions. A solution containing 11 OMPs was treated with short (<2 ms) and high-intensity light pulses produced by a Xenon flash lamp. It was observed that the HIPL parameters, such as the number of pulses and optical energy dose, have a significant impact on the efficiency of the treatment. The main advantage of HIPL is the fast kinetics that allows efficient photodegradation of OMPs from the aqueous solution rapidly and within milliseconds. The present work showcases the potential of HIPL technique for the post-treatment of contaminated water containing pharmaceuticals and endocrine disruptor compounds.
    • Superposition of Emergent Monopole and Antimonopole in CoTb Thin Films

      Guang, Yao; Ran, Kejing; Zhang, Junwei; Liu, Yizhou; Zhang, Senfu; Qiu, Xuepeng; Peng, Yong; Zhang, Xixiang; Weigand, Markus; Gräfe, Joachim; Schütz, Gisela; van der Laan, Gerrit; Hesjedal, Thorsten; Zhang, Shilei; Yu, Guoqiang; Han, Xiufeng (Physical Review Letters, American Physical Society (APS), 2021-11-16) [Article]
      A three-dimensional singular point that consists of two oppositely aligned emergent monopoles is identified in continuous CoTb thin films, as confirmed by complementary techniques of resonant elastic x-ray scattering, Lorentz transmission electron microscopy, and scanning transmission x-ray microscopy. This new type of topological defect can be regarded as a superposition of an emergent magnetic monopole and an antimonopole, around which the source and drain of the magnetic flux overlap in space. We experimentally prove that the observed spin twist seen in Lorentz transmission electron microscopy reveals the cross section of the superimposed three-dimensional structure, providing a straightforward strategy for the observation of magnetic singularities. Such a quasiparticle provides an excellent platform for studying the rich physics of emergent electromagnetism.
    • All-inorganic halide-perovskite-polymer luminescent fibers for high-bitrate ultraviolet free-space optical communication

      Kang, Chun Hong; Alkhazragi, Omar; Sinatra, Lutfan; Alshaibani, Sultan; Li, Kuang-Hui; Kong, Meiwei; Lutfullin, Marat; Bakr, Osman; Ng, Tien Khee; Ooi, Boon S. (IEEE, 2021-11-13) [Conference Paper]
      We demonstrate, for the first time, halide-perovskite-polymer-based luminescent fibers as a high-bitrate and near-omnidirectional photodetection platform for 375-nm ultraviolet laser-based free-space optical communication. Our demonstrations could enable future ultraviolet-to-visible optical receivers based on all-inorganic halide-perovskite nanomaterial to cater various dynamic scenarios in optical wireless communication.
    • Orientation Heredity in The Transformation of Two-Dimensional Epitaxial Films

      Xu, Xiangming; Smajic, Jasmin; Li, Kuang-hui; Min, Jung-Wook; Lei, Yongjiu; Davaasuren, Bambar; He, Xin; Zhang, Xixiang; Ooi, Boon S.; Da Costa, Pedro M. F. J.; Alshareef, Husam N. (Advanced Materials, Wiley, 2021-11-11) [Article]
      Controlling the lattice orientation is significant for both two-dimensional (2D) vdW layered and non-layered film growth process. Here we report a unique and universal phenomena termed lattice orientation heredity (LOH). The LOH enables product films (including 2D layered materials) to inherit the lattice orientation from reactant films in a chemical conversion process, excluding the requirement on the substrate lattice order. We demonstrate the process universality by investigating the lattice transformations in the carbonization, nitridation, and sulfurization of epitaxial MoO2, ZnO, and In2O3 thin films. Their resultant compounds all inherit mono-oriented feature from their precursor oxides, including 2D vdW layered semiconductors (e.g., MoS2), metallic films (e.g., MXene-like Mo2C and MoN), wide bandgap semiconductors (e.g., hexagonal ZnS), and ferroelectric semiconductors (e.g., In2S3). Using LOH-grown MoN as a seeding layer, we achieved mono-oriented GaN on an amorphous quartz substrate. The LOH process is a universal strategy capable of growing epitaxial thin films (including 2D vdW layered materials) not only on single-crystalline but also the non-crystalline.
    • Structure of monolayer 2H−TaS2 on Au(111)

      Silva, Caio C.; Dombrowski, Daniela; Samad, Abdus; Cai, Jiaqi; Jolie, Wouter; Hall, Joshua; Ryan, Paul T. P.; Thakur, Pardeep K.; Duncan, David A.; Lee, Tien-Lin; Schwingenschlögl, Udo; Busse, Carsten (Physical Review B, American Physical Society (APS), 2021-11-09) [Article]
      We determined the structure of epitaxial 2H-TaS2 on Au(111) using the method of x-ray standing waves (XSW), supported by density functional theory (DFT) calculations and scanning tunneling microscopy (STM). The lattice mismatch between substrate and overlayer gives rise to a moiré superstructure, which modulates the structural and electronic properties. For a specific registry (S atoms directly above Au substrate atoms), local covalentlike bonds form, whereas globally weak van der Waals bonding prevails. Still, the TaS2 layer remains rather flat. Significant charge transfer from Au(111) into the conduction band of the two-dimensional material is found.
    • Controlled Deposition of Zinc Metal Anodes via Selectively Polarized Ferroelectric Polymers

      Wang, Yizhou; Guo, Tianchao; Yin, Jian; Tian, Zhengnan; Ma, Yinchang; Liu, Zhixiong; Zhu, Yunpei; Alshareef, Husam N. (Advanced Materials, Wiley, 2021-11-09) [Article]
      Aqueous zinc ion batteries are regarded as ideal candidates for stationary energy storage systems due to their low cost and high safety. However, zinc can readily grow into dendrites, leading to limited cycling performance and quick failure of the batteries. Herein, we propose a novel strategy to mitigate this dendrite problem, in which selectively-polarized ferroelectric polymer material (poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))) is employed as a surface protective layer on zinc anodes. Such a polarized ferroelectric polymer layer could enable a locally-concentrated zinc ion distribution along the coated surface and thus enable the horizontal growth of zinc plates. As a result, symmetrical zinc batteries using such anodes exhibits long cycling lifespan at 0.2 mA cm−2, 0.2 mAh cm−2 for 2000 hours, and a high rate performance up to 15 mA cm−2. Also, the full cell (including Zn-MnO2 battery and zinc ion capacitor) based on this anode has been demonstrated. This work provides a novel strategy to protect the zinc anode and even other metal anodes exploiting polymer ferroelectricity.
    • A Low-Power CuSCN Hydrogen Sensor Operating Reversibly at Room Temperature

      Kabitakis, Viktoras; Gagaoudakis, Emmanouil; Moschogiannaki, Marilena; Kiriakidis, George; Seitkhan, Akmaral; Firdaus, Yuliar; Faber, Hendrik; Yengel, Emre; Loganathan, Kalaivanan; Deligeorgis, George; Tsetseris, Leonidas; Anthopoulos, Thomas D.; Binas, Vassilios (Advanced Functional Materials, Wiley, 2021-11-06) [Article]
      Hydrogen is attractive as an abundant source for clean and renewable energy. However, due to its highly flammable nature in a range of concentrations, the need for reliable and sensitive sensor/monitoring technologies has become acute. Here a solid-state hydrogen sensor based on solution-processable p-type semiconductor copper thiocyanate (CuSCN) is developed and studied. Sensors incorporating interdigitated electrodes made of noble metals (gold, platinum, palladium) show excellent response to hydrogen concentration down to 200 ppm while simultaneously being able to operate reversibly at room temperature and at low power. Sensors incorporating Pd electrodes show the highest signal response of 179% with a response time of ≈400 s upon exposure to 1000 ppm of hydrogen gas. The experimental findings are corroborated by density functional theory calculations, which highlight the role of atomic hydrogen species created upon interaction with the noble metal electrode as the origin for the increased p-type conductivity of CuSCN during exposure. The work highlights CuSCN as a promising sensing element for low-power, all-solid-state printed hydrogen sensors.
    • Resonance-mediated dynamic modulation of perovskite crystallization for efficient and stable solar cells

      Xu, Ligang; Wu, Di; Lv, Wenxuan; Xiang, Yuan; Liu, Yan; Tao, Ye; Yin, Jun; Qian, Mengyuan; Li, Ping; Zhang, Liuquan; Chen, Shufen; Mohammed, Omar F.; Bakr, Osman; Duan, Zheng; Chen, Runfeng; Huang, Wei (Advanced Materials, Wiley, 2021-11-05) [Article]
      Manipulating perovskite crystallization to prepare high-quality perovskite films is the key to achieve highly efficient and stable perovskite solar cells (PSCs). Here, we report a dynamic strategy to modulate perovskite crystallization using a resonance hole-transporting material (HTM) capable of fast self-adaptive tautomerization between multiple electronic states with neutral and charged resonance forms for mediating perovskite crystal growth and defects passivation in situ. This approach, based on resonance variation with self-adaptive molecular interactions between HTM and perovskite, produces high-quality perovskite films with smooth surface, oriented crystallization and low charge recombination, leading to high-performance inverted PSCs with power conversion efficiencies approaching to 22% for small-area devices (0.09 cm2) and up to 19.5% for large-area devices (1.02 cm2). Also, remarkably high stability of the PSCs was observed, retaining over 90%, 88%, or 83% of the initial efficiencies in air with relative humidity of 40∼50%, under continuous one-sun illumination, or at 75°C annealing for 1000 h without encapsulation.
    • Graphitic Cathodes for Aluminum Batteries with Aqueous Electrolytes

      Smajic, Jasmin; Alazmi, Amira; Wehbe, Nimer; Da Costa, Pedro M. F. J. (Cambridge University Press (CUP), 2021-11-05) [Preprint]
      Concerns over lithium-ion battery safety and environmental impact have led to increased exploration of alternative energy storage systems. Of these, aluminum is of particular interest, being environmentally friendly, safe and easy to handle. In this work, we explore graphitic cathodes with an aqueous electrolyte (aluminum trifluoromethanesulfonate) and study their electrochemical performance. Finally, a reduced graphene cathode with tailored porosity results in an eco-friendly and inherently safe rechargeable battery with promising electrochemical performance
    • High-Capacity NH4+ Charge Storage in Covalent Organic Frameworks

      Tian, Zhengnan; Kale, Vinayak Swamirao; Wang, Yizhou; Kandambeth, Sharath; Czaban-Jozwiak, Justyna; Shekhah, Osama; Eddaoudi, Mohamed; Alshareef, Husam N. (Journal of the American Chemical Society, American Chemical Society (ACS), 2021-11-05) [Article]
      Ammonium ions (NH4+), as non-metallic charge carriers, have spurred great research interest in the realm of aqueous batteries. Unfortunately, most inorganic host materials used in these batteries are still limited by the sluggish diffusion kinetics. Here, we report a unique hydrogen bond chemistry to employ covalent organic frameworks (COFs) for NH4+ ion storage, which achieves a high capacity of 220.4 mAh g–1 at a current density of 0.5 A g–1. Combining the theoretical simulation and materials analysis, a universal mechanism for the reaction of nitrogen and oxygen bridged by hydrogen bonds is revealed. In addition, we explain the solvation behavior of NH4+, leading to a relationship between redox potential and desolvation energy barrier. This work provides a new insight into NH4+ ion storage in host materials based on hydrogen bond chemistry. This mechanism can be leveraged to design and develop COFs for electrochemical energy storage.
    • Over 18% ternary polymer solar cells enabled by a terpolymer as the third component

      Peng, Wenhong; Lin, Yuanbao; Jeong, Sang Young; Genene, Zewdneh; Magomedov, Artiom; Woo, Han Young; Chen, Cailing; Wahyudi, Wandi; Tao, Qiang; Deng, Jiyong; Han, Yu; Getautis, Vytautas; Zhu, Weiguo; Anthopoulos, Thomas D.; Wang, Ergang (Nano Energy, Elsevier BV, 2021-11-05) [Article]
      “Ternary blending” and “random terpolymerization” strategies have both proven effective for enhancing the performance of organic solar cells (OSCs). However, reports on the combination of the two strategies remain rare. Here, a terpolymer PM6-Si30 was constructed by inserting chlorine and alkylsilyl-substituted benzodithiophene (BDT) unit (0.3 equivalent) into the state-of-the-art polymer PM6. The terpolymer exhibitsadeep highest-occupied-molecular-orbital energy and good miscibility with both PM6 and BTP-eC9 (C9) and enables its use as a third component into PM6:PM6-Si30:C9 bulk-heterojunction for OSCs. The resulting cells exhibit maximum power conversion efficiency (PCE) of 18.27%, which is higher than that obtained for the optimized control binary PM6:C9-based OSC (17.38%). The enhanced performance of the PM6:PM6-Si30:C9 cells is attributed to improved charge transport, favorable molecular arrangement, reduced energy loss and suppressed bimolecular recombination. The work demonstrates the potential of random terpolymer as a third component in OSCs and highlights a new strategy for the construction of a ternary system with improved photovoltaic performance.
    • A Tri-Channel Oxide Transistor Concept for the Rapid Detection of Biomolecules Including the SARS-CoV-2 Spike Protein

      Lin, Yen-Hung; Han, Yang; Sharma, Abhinav; AlGhamdi, Wejdan S.; Liu, Chien-Hao; Chang, Tzu-Hsuan; Xiao, Xi-Wen; Lin, Wei-Zhi; Lu, Po-Yu; Seitkhan, Akmaral; Mottram, Alexander D.; Pattanasattayavong, Pichaya; Faber, Hendrik; Heeney, Martin; Anthopoulos, Thomas D. (Advanced Materials, Wiley, 2021-11-04) [Article]
      Solid-state transistor sensors that can detect biomolecules in real time are highly attractive for emerging bioanalytical applications. However, combining upscalable manufacturing with the required performance remains challenging. Here we develop an alternative biosensor transistor concept that relies on a solution-processed In2O3/ZnO semiconducting heterojunction featuring a geometrically engineered tri-channel architecture for the rapid, real-time detection of important biomolecules. The sensor combines a high electron mobility channel, attributed to the electronic properties of the In2O3/ZnO heterointerface, in close proximity to a sensing surface featuring tethered analyte receptors. The unusual tri-channel design enables strong coupling between the buried electron channel and electrostatic perturbations occurring during receptor-analyte interactions allowing for robust, real-time detection of biomolecules down to attomolar (aM) concentrations. The experimental findings are corroborated by extensive device simulations, highlighting the unique advantages of the heterojunction tri-channel design. By functionalizing the surface of the geometrically-engineered channel with SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) antibody receptors, we demonstrate real-time detection of the SARS-CoV-2 spike S1 protein down to aM concentrations in under two minutes in physiological relevant conditions.
    • Inducing Half-Metallicity in Monolayer MoSi2N4

      Ray, Avijeet; Tyagi, Shubham; Singh, Nirpendra; Schwingenschlögl, Udo (ACS Omega, American Chemical Society (ACS), 2021-11-04) [Article]
      First-principles calculations are performed for the recently synthesized monolayer MoSi2N4 [Science 369, 670–674 (2020)]. We show that N vacancies are energetically favorable over Si vacancies, except for Fermi energies close to the conduction band edge in the N-rich environment, and induce half-metallicity. N and Si vacancies generate magnetic moments of 1.0 and 2.0 μB, respectively, with potential applications in spintronics. We also demonstrate that N and Si vacancies can be used to effectively engineer the work function.
    • Sputtered transparent electrodes for optoelectronic devices: Induced damage and mitigation strategies

      Aydin, Erkan; Altinkaya, Cesur; Smirnov, Yury; Yaqin, Muhammad A.; Zanoni, Kassio P.S.; Paliwal, Abhyuday; Firdaus, Yuliar; Allen, Thomas; Anthopoulos, Thomas D.; Bolink, Henk J.; Morales-Masis, Monica; De Wolf, Stefaan (Matter, Elsevier BV, 2021-11-03) [Article]
      Transparent electrodes and metal contacts deposited by magnetron sputtering find applications in numerous state-of-the-art optoelectronic devices, such as solar cells and light-emitting diodes. However, the deposition of such thin films may damage underlying sensitive device layers due to plasma emission and particle impact. Inserting a buffer layer to shield against such damage is a common mitigation approach. We start this review by describing how sputtered transparent top electrodes have become archetypal for a broad range of optoelectronic devices and then discuss the possible detrimental consequences of sputter damage on device performance. Next, we review common buffer-layer materials in view of their processingproperty-performance relationship. Finally, we discuss strategies to eliminate the buffer-layer requirement by implementing alternative, soft-landing deposition techniques for top electrodes. Our review highlights the critical issue of sputter damage for optoelectronic devices, formulates mitigation strategies, and provides cross-field learnings that can lead to more efficient and reliable optoelectronic devices aimed for commercialization.