Introduction: Two-Dimensional Layered Transition Metal Dichalcogenides

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Learn More CiteCitationCitation and abstractCitation and referencesMore citation options ShareShare onFacebookX (Twitter)WeChatLinkedInRedditEmailJump toExpandCollapse EditorialOctober 9, 2024Introduction: Two-Dimensional Layered Transition Metal DichalcogenidesClick to copy article linkArticle link copied!Xiangfeng Duan*Xiangfeng DuanDepartment of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United StatesCalifornia NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States*E-mail: [email protected]More by Xiangfeng DuanView Biographyhttps://orcid.org/0000-0002-4321-6288Hua Zhang*Hua ZhangDepartment of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, ChinaHong Kong Institute for Clean Energy, City University of Hong Kong, Hong Kong, ChinaHong Kong Branch of National Precious Metals Material Engineering Research Center (NPMM), City University of Hong Kong, Hong Kong, ChinaShenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China*E-mail: [email protected]More by Hua ZhangView Biographyhttps://orcid.org/0000-0001-9518-740XOpen PDFChemical ReviewsCite this: Chem. Rev. 2024, 124, 19, 10619–10622Click to copy citationCitation copied!https://pubs.acs.org/doi/10.1021/acs.chemrev.4c00586https://doi.org/10.1021/acs.chemrev.4c00586Published October 9, 2024 Publication History Received 6 August 2024Published online 9 October 2024Published in issue 9 October 2024editorialCopyright © Published 2024 by American Chemical Society. This publication is available under these Terms of Use. Request reuse permissionsThis publication is licensed for personal use by The American Chemical Society. ACS PublicationsCopyright © Published 2024 by American Chemical SocietySubjectswhat are subjectsArticle subjects are automatically applied from the ACS Subject Taxonomy and describe the scientific concepts and themes of the article.Chemical vapor depositionEnergy storageExfoliationHeterostructuresLayersSpecial IssuePublished as part of Chemical Reviews special issue "Two-Dimensional Layered Transition Metal Dichalcogenides".Two-dimensional (2D) materials have attracted tremendous attention in recent years, with transition metal dichalcogenides (TMDs) representing a particularly intriguing class. (1−3) TMDs consist of a transition metal atom (such as Mo, W, or Ti) sandwiched between two chalcogen atoms (S, Se, or Te), forming an MX2 stoichiometry. Characterized by their unique layered structures, the weak van der Waals forces between the covalently bonded atomic crystalline layers allow them to be exfoliated into single- or few-layer sheets, displaying properties that are markedly different from those of their bulk counterparts. For example, the reduced dimensionality leads to a direct bandgap in many TMDs, unlike the indirect bandgap in their bulk form, making them suitable for optoelectronic applications such as photodetectors, light-emitting diodes, and solar cells. (3−9) The unique properties and potential applications of TMDs are driving significant advancements in various fields, from electronics to energy storage and beyond. (10−16) This virtual thematic issue is dedicated to exploring the latest developments and future directions in the research and application of 2D-TMDs.The scalable preparation of the atomically thin 2D-TMDs in large quantity or large area is foundational for capturing their potential in diverse technologies. Considerable efforts have been devoted to the preparation of various forms of 2D-TMDs, including mechanical exfoliation, chemical vapor deposition (CVD), and liquid-phase exfoliation. (17−24) Mechanical exfoliation, though versatile for producing diverse flakes, is limited in scalability and reproducibility. CVD offers better control over thickness and size, making it suitable for large-area production of high quality monolayers or thin films. Liquid-phase exfoliation is advantageous for producing solution-processable TMD inks, essential for printable electronics or energy applications that require bulk quantity of monolayer or few-layer TMDs. Additionally, TMDs often exist in different phases, such as 1T, 1T′, 2H, and 3R, each with distinct chemical or electronic properties. For instance, the 2H phase MoS2 is semiconducting, while the 1T and 1T′ phases are metallic and semimetallic, respectively. Thus, phase engineering of nanomaterials (PEN) plays a critical role in tailoring the properties of TMDs. Control over these phases can be achieved through techniques like doping, strain engineering, and chemical treatments, enabling the customization of TMD properties for specific applications. (25) Furthermore, the nonbonding van der Waals interactions between the covalently bonded TMD atomic layers allow for the flexible intercalation of foreign atoms or molecules, forming self-assembled interlayers between the crystalline atomic layers without disrupting the in-plane covalent bonds. This capability opens up another direction for tailoring and tuning the physical properties of TMDs. (11,26−29)With versatile variability in chemical compositions, layer numbers and structural symmetries, the TMD materials exhibit highly tunable electronic, optical, and mechanical properties, making them highly versatile for diverse applications from electronics to energy storage and beyond. The direct bandgap and high carrier mobility of TMDs at the limit of subnanometer thickness make them ideal for next-generation electronic and optoelectronic devices. They are being intensively explored for use in transistors, flexible displays, and photodetectors. TMD-based transistors, for example could promise reduced power consumption and increased switching speeds compared to traditional silicon-based devices. (3,30,31) The atomically thin geometry and highly surface sensitive electronic properties make 2D-TMDs an attractive material platform for chemical and biological sensors. Their ability to detect low concentrations of gases or biomolecules with high selectivity and sensitivity opens up new possibilities for environmental monitoring and medical diagnostics. (32−35) The large surface area and tunable electronic properties of 2D-TMDs make them highly tunable catalysts for diverse reactions including green hydrogen production. Additionally, TMDs have shown potential in energy storage devices such as lithium-ion batteries and supercapacitors. Their high surface area and layered structure can facilitate efficient ion transport and storage. TMD-based anodes in lithium-ion batteries, for instance, can provide higher capacity and longer cycle life compared to the conventional materials. (36−38)While it is difficult to cover all the relevant topics of this rapidly expanding field, this virtual thematic issue brings together leaders in the field of diverse backgrounds to discuss the latest developments, trends, and future directions in 2D-TMDs. From the outset, Kaihui Liu et al. addressed the critical need for scalable production of large-area TMD thin films, providing a comprehensive overview of the epitaxial growth of TMDs, including wafer-scale production and epitaxial growth of single-crystals. (21) Xidong Duan et al. systematically summarized the latest techniques for fabricating TMD heterostructures, discussing the rationale, mechanisms and advantages of each strategy, highlighted the representative applications of 2D-TMD heterostructures in various technological areas, and discussed the challenges and future perspectives in the synthesis and device fabrication of TMD heterostructures. (39) Zhaoyang Lin and Xiangfeng Duan et al. reviewed the development of solution-processable 2D-TMD inks, discussing the chemical synthesis of these inks and the techniques for their deposition and highlighting their potential for scalable and cost-effective production of thin films for diverse applications in electronics and optoelectronics. (20) The review concludes with an analysis of the key challenges and future research directions for advancing the technology of 2D-TMD inks. Hua Zhang et al. explored the critical role of crystal phases in determining the properties of TMD materials, providing a comprehensive overview of the synthetic PEN strategies for TMDs, highlighting the importance of controlling both conventional and metastable phases for applications in various fields, including electronics and catalysis, and offer perspectives on future challenges and opportunities in the domain. (25)Yuan Liu et al. examined the challenges of forming high-quality metal contacts with 2D-TMDs due to their ultrathin structures and highlighted van der Waals (vdW) contacts as a low-energy alternative to conventional metallization methods. They discussed recent advancements in vdW contacted devices, their unique transport properties, and their promise for realizing unprecedented device performance, providing a comprehensive analysis of the current research landscape and future prospects in this rapidly evolving field. (40) Yongmin He and Zheng Liu presented an overview of microcell-based studies of TMD electrocatalysts, summarizing advances in understanding TMD catalysts at the single fake (device) level, discussing challenges and future directions in this innovative research area, and highlighting the advantages of spatial confinement for catalytic site exposure. (41) Finally, Pulickel Ajayan et al. reviewed the application of 2D-TMDs in energy conversion and storage, (42) highlighting significant advancements in phase, size, composition, and defect engineering of TMDs, aimed at optimizing their performances for applications like electrocatalytic water splitting and alkali ion batteries. They also provided critical insights into ongoing research and future directions in designing TMDs for energy solutions.Despite significant progress to date, the reliable and large-scale synthesis of high-quality, defect-free TMDs remains a significant hurdle. Achieving precise and reproducible control over the phase and composition of TMDs is another challenge that needs to be addressed. (43) Moreover, integrating TMDs into existing technologies and systems requires further research to understand their long-term stability and performance. Future research in 2D-TMDs is likely to focus on improving synthesis techniques, exploring new phases and heterostructures, and developing novel applications. The ongoing advancements in characterization tools and computational methods will also play a crucial role in understanding and optimizing TMD properties. Overall, 2D-TMDs represent a vibrant and rapidly evolving field of research. Their unique properties and versatile applications have the potential to drive significant advancements across various technological domains, paving the way for innovative solutions to contemporary scientific and engineering challenges. This virtual thematic issue underscores the transformative potential of 2D-TMDs and aims to inspire further research and innovation in this dynamic field.Author InformationClick to copy section linkSection link copied!Corresponding AuthorsXiangfeng Duan, Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States; California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States, https://orcid.org/0000-0002-4321-6288, Email: [email protected]Hua Zhang, Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China; Hong Kong Institute for Clean Energy, City University of Hong Kong, Hong Kong, China; Hong Kong Branch of National Precious Metals Material Engineering Research Center (NPMM), City University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China, https://orcid.org/0000-0001-9518-740X, Email: [email protected]NotesViews expressed in this editorial are those of the authors and not necessarily the views of the ACS.BiographiesClick to copy section linkSection link copied!Xiangfeng DuanHigh Resolution ImageDownload MS PowerPoint SlideXiangfeng Duan received his B.S. degree from the University of Science and Technology of China in 1997 and his Ph.D. degree from Harvard University in 2002. From 2002 to 2008, he was a Founding Scientist at Nanosys Inc., a nanotechnology startup partly based on his doctoral research. Dr. Duan joined UCLA in 2008 with a Howard Reiss Career Development Chair. He was promoted to Associate Professor in 2012 and advanced to Full Professor in 2013. His research focuses on nanoscale materials and devices, with applications in next-generation electronics, energy solutions, and health technologies.Hua ZhangHigh Resolution ImageDownload MS PowerPoint SlideHua Zhang is the Herman Hu Chair Professor of Nanomaterials at the City University of Hong Kong. He completed his Ph.D. at Peking University (1998). As a postdoctoral fellow, he joined Katholieke Universiteit Leuven (1999) and moved to Northwestern University (2001). After working at NanoInk Inc. (USA) and the Institute of Bioengineering and Nanotechnology (Singapore), he joined Nanyang Technological University in 2006 and moved to the City University of Hong Kong in 2019. His current research interests focus on the phase engineering of nanomaterials (PEN), especially the preparation of novel metallic and 2D nanomaterials with unconventional phases, and epitaxial growth of heterostructures for various applications.ReferencesClick to copy section linkSection link copied! This article references 43 other publications. 1Geim, A. K.; Novoselov, K. S. The Rise of Graphene. Nat. Mater. 2007, 6 (3), 183– 191, DOI: 10.1038/nmat1849 Google Scholar1The rise of grapheneGeim, A. K.; Novoselov, K. S.Nature Materials (2007), 6 (3), 183-191CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group) A review. Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when com. products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top expts. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXit1Khtrg%253D&md5=c2c02ce70a1725e6c559c173156568c52Liao, L.; Lin, Y.-C.; Bao, M.; Cheng, R.; Bai, J.; Liu, Y.; Qu, Y.; Wang, K. L.; Huang, Y.; Duan, X. High-Speed Graphene Transistors with a Self-Aligned Nanowire Gate. Nature 2010, 467 (7313), 305– 308, DOI: 10.1038/nature09405 Google Scholar2High-speed graphene transistors with a self-aligned nanowire gateLiao, Lei; Lin, Yung-Chen; Bao, Mingqiang; Cheng, Rui; Bai, Jingwei; Liu, Yuan; Qu, Yongquan; Wang, Kang L.; Huang, Yu; Duan, XiangfengNature (London, United Kingdom) (2010), 467 (7313), 305-308CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group) Graphene has attracted considerable interest as a potential new electronic material. With its high carrier mobility, graphene is of particular interest for ultrahigh-speed radio-frequency electronics. However, conventional device fabrication processes cannot readily be applied to produce high-speed graphene transistors because they often introduce significant defects into the monolayer of C lattices and severely degrade the device performance. Here we report an approach to the fabrication of high-speed graphene transistors with a self-aligned nanowire gate to prevent such degrdn. A Co2Si-Al2O3 core-shell nanowire is used as the gate, with the source and drain electrodes defined through a self-alignment process and the channel length defined by the nanowire diam. The phys. assembly of the nanowire gate preserves the high carrier mobility in graphene, and the self-alignment process ensures that the edges of the source, drain and gate electrodes are automatically and precisely positioned so that no overlapping or significant gaps exist between these electrodes, thus minimizing access resistance. It therefore allows for transistor performance not previously possible. Graphene transistors with a channel length as low as 140 nm were fabricated with the highest scaled on-current (3.32 mA μm-1) and transconductance (1.27 mSμm-1) reported so far. Significantly, on-chip microwave measurements demonstrate that the self-aligned devices have a high intrinsic cut-off (transit) frequency of fT = 100-300 GHz, with the extrinsic fT (in the range of a few gigahertz) largely limited by parasitic pad capacitance. The reported intrinsic fT of the graphene transistors is comparable to that of the very best high-electron-mobility transistors with similar gate lengths. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFSisLfI&md5=169a893480fcacdce1740c124ff55ed13Radisavljevic, B.; Radenovic, A.; Brivio, J.; Giacometti, V.; Kis, A. Single-Layer MoS2 Transistors. Nat. Nanotechnol. 2011, 6 (3), 147– 150, DOI: 10.1038/nnano.2010.279 Google Scholar3Single-layer MoS2 transistorsRadisavljevic, B.; Radenovic, A.; Brivio, J.; Giacometti, V.; Kis, A.Nature Nanotechnology (2011), 6 (3), 147-150CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group) Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to 1D materials, it is relatively easy to fabricate complex structures from them. The most widely studied 2D material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained Si films or requires high voltages. Although single layers of MoS2 have a large intrinsic bandgap of 1.8 eV, previously reported mobilities in the 0.5-3 cm2 V-1 s-1 range are too low for practical devices. Here, we use a HfO2 gate dielec. to demonstrate a room-temp. single-layer MoS2 mobility of at least 200 cm2 V-1 s-1, similar to that of graphene nanoribbons, and demonstrate transistors with room-temp. current on/off ratios of 1 × 108 and ultralow standby power dissipation. Because monolayer MoS2 has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS2 could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXislCjsro%253D&md5=555366539a8a87d074a69674aafaf3154Wang, Q. H.; Kalantar-Zadeh, K.; Kis, A.; Coleman, J. N.; Strano, M. S. Electronics and Optoelectronics of Two-Dimensional Transition Metal Dichalcogenides. Nat. Nanotechnol. 2012, 7 (11), 699– 712, DOI: 10.1038/nnano.2012.193 Google Scholar4Electronics and optoelectronics of two-dimensional transition metal dichalcogenidesWang, Qing Hua; Kalantar-Zadeh, Kourosh; Kis, Andras; Coleman, Jonathan N.; Strano, Michael S.Nature Nanotechnology (2012), 7 (11), 699-712CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group) A review. The remarkable properties of graphene have renewed interest in inorg., two-dimensional materials with unique electronic and optical attributes. Transition metal dichalcogenides (TMDCs) are layered materials with strong in-plane bonding and weak out-of-plane interactions enabling exfoliation into two-dimensional layers of single unit cell thickness. Although TMDCs were studied for decades, recent advances in nanoscale materials characterization and device fabrication have opened up new opportunities for two-dimensional layers of thin TMDCs in nanoelectronics and optoelectronics. TMDCs such as MoS2, MoSe2, WS2 and WSe2 have sizable bandgaps that change from indirect to direct in single layers, allowing applications such as transistors, photodetectors and electroluminescent devices. The authors review the historical development of TMDCs, methods for prepg. atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1ajtr7P&md5=4e45d586c6ac7b0676a461f61a53db685Palacios-Berraquero, C.; Barbone, M.; Kara, D. M.; Chen, X.; Goykhman, I.; Yoon, D.; Ott, A. K.; Beitner, J.; Watanabe, K.; Taniguchi, T.; Ferrari, A. C.; Atatüre, M. Atomically Thin Quantum Light-Emitting Diodes. Nat. Commun. 2016, 7 (1), 12978, DOI: 10.1038/ncomms12978 Google Scholar5Atomically thin quantum light-emitting diodesPalacios-Berraquero, Carmen; Barbone, Matteo; Kara, Dhiren M.; Chen, Xiaolong; Goykhman, Ilya; Yoon, Duhee; Ott, Anna K.; Beitner, Jan; Watanabe, Kenji; Taniguchi, Takashi; Ferrari, Andrea C.; Atature, MeteNature Communications (2016), 7 (), 12978CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group) Transition metal dichalcogenides are optically active, layered materials promising for fast optoelectronics and on-chip photonics. We demonstrate elec. driven single-photon emission from localized sites in tungsten diselenide and tungsten disulfide. To achieve this, we fabricate a light-emitting diode structure comprising single-layer graphene, thin hexagonal boron nitride and transition metal dichalcogenide mono- and bi-layers. Photon correlation measurements are used to confirm the single-photon nature of the spectrally sharp emission. These results present the transition metal dichalcogenide family as a platform for hybrid, broadband, atomically precise quantum photonics devices. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsF2qs73O&md5=a43d92751e13058d9e73b0f53a82f3ed6Li, C.; Cao, Q.; Wang, F.; Xiao, Y.; Li, Y.; Delaunay, J.-J.; Zhu, H. Engineering Graphene and TMDs Based van Der Waals Heterostructures for Photovoltaic and Photoelectrochemical Solar Energy Conversion. Chem. Soc. Rev. 2018, 47 (13), 4981– 5037, DOI: 10.1039/C8CS00067K Google Scholar6Engineering graphene and TMDs based van der Waals heterostructures for photovoltaic and photoelectrochemical solar energy conversionLi, Changli; Cao, Qi; Wang, Faze; Xiao, Yequan; Li, Yanbo; Delaunay, Jean-Jacques; Zhu, HongweiChemical Society Reviews (2018), 47 (13), 4981-5037CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry) Graphene and two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted significant interest due to their unique properties that cannot be obtained in their bulk counterparts. These atomically thin 2D materials have demonstrated strong light-matter interactions, tunable optical bandgap structures and unique structural and elec. properties, rendering possible the high conversion efficiency of solar energy with a minimal amt. of active absorber material. The isolated 2D monolayer can be stacked into arbitrary van der Waals (vdWs) heterostructures without the need to consider lattice matching. Several combinations of 2D/3D and 2D/2D materials have been assembled to create vdWs heterojunctions for photovoltaic (PV) and photoelectrochem. (PEC) energy conversion. However, the complex, less-constrained, and more environmentally vulnerable interface in a vdWs heterojunction is different from that of a conventional, epitaxially grown heterojunction, engendering new challenges for surface and interface engineering. In this review, the physics of band alignment, the chem. of surface modification and the behavior of photoexcited charge transfer at the interface during PV and PEC processes will be discussed. We will present a survey of the recent progress and challenges of 2D/3D and 2D/2D vdWs heterojunctions, with emphasis on their applicability to PV and PEC devices. Finally, we will discuss emerging issues yet to be explored for 2D materials to achieve high solar energy conversion efficiency and possible strategies to improve their performance. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXptValsLc%253D&md5=96490412c2c6cf9ff436aaaa83a871fc7Nassiri Nazif, K.; Daus, A.; Hong, J.; Lee, N.; Vaziri, S.; Kumar, A.; Nitta, F.; Chen, M. E.; Kananian, S.; Islam, R.; Kim, K.-H.; Park, J.-H.; Poon, A. S. Y.; Brongersma, M. L.; Pop, E.; Saraswat, K. C. High-Specific-Power Flexible Transition Metal Dichalcogenide Solar Cells. Nat. Commun. 2021, 12 (1), 7034, DOI: 10.1038/s41467-021-27195-7 Google Scholar7High-specific-power flexible transition metal dichalcogenide solar cellsNassiri Nazif, Koosha; Daus, Alwin; Hong, Jiho; Lee, Nayeun; Vaziri, Sam; Kumar, Aravindh; Nitta, Frederick; Chen, Michelle E.; Kananian, Siavash; Islam, Raisul; Kim, Kwan-Ho; Park, Jin-Hong; Poon, Ada S. Y.; Brongersma, Mark L.; Pop, Eric; Saraswat, Krishna C.Nature Communications (2021), 12 (1), 7034CODEN: NCAOBW; ISSN:2041-1723. (Nature Research) Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coeffs., desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact-TMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addn., fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightwt. flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4 W g-1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46 W g-1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXislWktLrP&md5=357c0f3fcb4c3b5c2ba41e8f1c06726a8Strauß, F.; Zeng, Z.; Braun, K.; Scheele, M. Toward Gigahertz Photodetection with Transition Metal Dichalcogenides. Acc. Chem. Res. 2024, 57 (10), 1488– 1499, DOI: 10.1021/acs.accounts.4c00088 Google ScholarThere is no corresponding record for this reference.9Zhang, K.; Zhang, T.; Cheng, G.; Li, T.; Wang, S.; Wei, W.; Zhou, X.; Yu, W.; Sun, Y.; Wang, P.; Zhang, D.; Zeng, C.; Wang, X.; Hu, W.; Fan, H. J.; Shen, G.; Chen, X.; Duan, X.; Chang, K.; Dai, N. Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe 2 /MoS 2 van Der Waals Heterostructures. ACS Nano 2016, 10 (3), 3852– 3858, DOI: 10.1021/acsnano.6b00980 Google Scholar9Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe2/MoS2 van der Waals HeterostructuresZhang, Kenan; Zhang, Tianning; Cheng, Guanghui; Li, Tianxin; Wang, Shuxia; Wei, Wei; Zhou, Xiaohao; Yu, Weiwei; Sun, Yan; Wang, Peng; Zhang, Dong; Zeng, Changgan; Wang, Xingjun; Hu, Weida; Fan, Hong Jin; Shen, Guozhen; Chen, Xin; Duan, Xiangfeng; Chang, Kai; Dai, NingACS Nano (2016), 10 (3), 3852-3858CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society) The type-II staggered band alignment in MoTe2/MoS2 van der Waals (vdW) heterostructures and an interla