Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.
Advertisement
npj 2D Materials and Applications , Article number: (2026)
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Transition metal dichalcogenide (TMD) solar cells are promising candidates for high-specific-power photovoltaics due to their strong light-matter interactions, such as their high absorption coefficients. The performance of many TMD solar devices is limited by recombination losses at the semiconductor and metal electrode interface. Recent studies with silicon and perovskite solar cells overcome this challenge by employing two carrier-selective contacts to improve carrier separation and collection. In this work, we design and demonstrate the first dual selective contact TMD solar cell with both electron and hole transport layers. Resembling inverted perovskite device architectures, this solar cell consists of a vertical-junction 10-nm-thick WS2 absorber layer, C60 electron-selective contact, and PTAA hole-selective contact. This photovoltaic device exhibits an AM1.5 G open-circuit voltage of 523 mV and a power conversion efficiency of 2.4%. We characterize the carrier dynamics in the dual selective contact solar cell, which include achieving balanced transport with symmetric carrier-selective contact conductance to achieve high fill factors. We demonstrate this by showing that S-shaped I–V curves can be eliminated through reducing the thickness of the low-conductance contact. From theoretical calculations, we find that the TMD carrier lifetime limits the open-circuit voltage of TMD solar cells. To move towards the voltage limit and achieve higher solar performance, we outline steps for improving the dual selective contact solar cell architecture.
The data that supports this study is available from the corresponding author upon reasonable request.
The simulation codes used in this study are in the Sentaurus TCAD and Lumerical FDTD software. The code that supports this study is available from the corresponding author upon reasonable request.
Bernardi, M., Palummo, M. & Grossman, J. C. Extraordinary sunlight absorption and one nanometer thick photovoltaics using two-dimensional monolayer materials. Nano Lett. 13, 3664–3670 (2013).
Google Scholar
Jariwala, D. et al. Near-unity absorption in van der Waals semiconductors for ultrathin optoelectronics. Nano Lett. 16, 5482–5487 (2016).
Google Scholar
Reese, M. O. et al. Increasing markets and decreasing package weight for high-specific-power photovoltaics. Nat. Energy 3, 1002–1012 (2018).
Google Scholar
Nassiri Nazif, K. et al. High-performance p–n junction transition metal dichalcogenide photovoltaic cells enabled by MoOx doping and passivation. Nano Lett. 21, 3443–3450 (2021).
Google Scholar
Svatek, S. A. et al. High open-circuit voltage in transition metal dichalcogenide solar cells. Nano Energy 79, 105427 (2021).
Google Scholar
Nassiri Nazif, K. et al. High-specific-power flexible transition metal dichalcogenide solar cells. Nat. Commun. 12, 7034 (2021).
Google Scholar
Nassiri Nazif, K., Nitta, F. U., Daus, A., Saraswat, K. C. & Pop, E. Efficiency limit of transition metal dichalcogenide solar cells. Commun. Phys. 6, 1–11 (2023).
Google Scholar
Li, H.-M. et al. Ultimate thin vertical p–n junction composed of two-dimensional layered molybdenum disulfide. Nat. Commun. 6, 6564 (2015).
Google Scholar
Wi, S. et al. Enhancement of photovoltaic response in multilayer MoS2 induced by plasma doping. ACS Nano 8, 5270–5281 (2014).
Google Scholar
Wong, J. et al. High photovoltaic quantum efficiency in ultrathin van der Waals heterostructures. ACS Nano 11, 7230–7240 (2017).
Google Scholar
Cho, A.-J., Song, M.-K., Kang, D.-W. & Kwon, J.-Y. Two-dimensional WSe2/MoS2 p–n heterojunction-based transparent photovoltaic cell and its performance enhancement by fluoropolymer passivation. ACS Appl. Mater. Interfaces 10, 35972–35977 (2018).
Google Scholar
Le Thi, H. Y. et al. Doping-free high-performance photovoltaic effect in a WSe2 lateral p-n homojunction formed by contact engineering. ACS Appl. Mater. Interfaces 15, 35342–35349 (2023).
Google Scholar
Tsai, M.-L. et al. Single Atomically Sharp Lateral Monolayer p-n Heterojunction Solar Cells with Extraordinarily High Power Conversion Efficiency. Adv. Mater. 29, 1701168 (2017).
Google Scholar
Islam, K. M., Ismael, T., Luthy, C., Kizilkaya, O. & Escarra, M. D. Large-area, high-specific-power schottky-junction photovoltaics from CVD-grown monolayer MoS2. ACS Appl. Mater. Interfaces 14, 24281–24289 (2022).
Google Scholar
Went, C. M. et al. A new metal transfer process for van der Waals contacts to vertical Schottky-junction transition metal dichalcogenide photovoltaics. Sci. Adv. 5, eaax6061 (2019).
Google Scholar
Akama, T. et al. Schottky solar cell using few-layered transition metal dichalcogenides toward large-scale fabrication of semitransparent and flexible power generator. Sci. Rep. 7, 11967 (2017).
Google Scholar
Shanmugam, M., Durcan, C. A. & Yu, B. Layered semiconductor molybdenum disulfide nanomembrane based Schottky-barrier solar cells. Nanoscale 4, 7399 (2012).
Google Scholar
McVay, E., Zubair, A., Lin, Y., Nourbakhsh, A. & Palacios, T. Impact of Al2O3 passivation on the photovoltaic performance of vertical WSe2 Schottky junction solar cells. ACS Appl. Mater. Interfaces 12, 57987–57995 (2020).
Google Scholar
Liu, Y. et al. Approaching the Schottky–Mott limit in van der Waals metal–semiconductor junctions. Nature 557, 696–700 (2018).
Google Scholar
Kim, K.-H. et al. High-efficiency WSe 2 photovoltaic devices with electron-selective contacts. ACS Nano 16, 8827–8836 (2022).
Google Scholar
Fu, Q. et al. Recent progress on the long-term stability of perovskite solar cells. Adv. Sci. 5, 1700387 (2018).
Google Scholar
Li, Z. et al. Organometallic-functionalized interfaces for highly efficient inverted perovskite solar cells. Science 376, 416–420 (2022).
Google Scholar
Green, M. A. et al. Solar cell efficiency tables (Version 63). Prog. Photovolt. Res. Appl. 32, 3–13 (2024).
Google Scholar
Lin, H. et al. Silicon heterojunction solar cells with up to 26.81% efficiency achieved by electrically optimized nanocrystalline-silicon hole contact layers. Nat. Energy 8, 789–799 (2023).
Google Scholar
Zheng, X. et al. Managing grains and interfaces via ligand anchoring enables 22.3%-efficiency inverted perovskite solar cells. Nat. Energy 5, 131–140 (2020).
Google Scholar
Gutierrez-Partida, E. et al. Large-grain double cation perovskites with 18 μs lifetime and high luminescence yield for efficient inverted perovskite solar cells. ACS Energy Lett. 6, 1045–1054 (2021).
Google Scholar
Li, F. et al. Regulating surface termination for efficient inverted perovskite solar cells with greater than 23% efficiency. J. Am. Chem. Soc. 142, 20134–20142 (2020).
Google Scholar
Onno, A., Chen, C., Koswatta, P., Boccard, M. & Holman, Z. C. Passivation, conductivity, and selectivity in solar cell contacts: concepts and simulations based on a unified partial-resistances framework. J. Appl. Phys. 126, 183103 (2019).
Google Scholar
Jariwala, D., Davoyan, A. R., Wong, J. & Atwater, H. A. Van der Waals materials for atomically-thin photovoltaics: promise and outlook. ACS Photonics 4, 2962–2970 (2017).
Google Scholar
Wang, S. et al. Improved Efficiency in WSe2 Solar Cells Using Amorphous InOx Heterocontacts. ACS Nano https://doi.org/10.1021/acsnano.4c06525 (2024).
Liu, S., Biju, V. P., Qi, Y., Chen, W. & Liu, Z. Recent progress in the development of high-efficiency inverted perovskite solar cells. NPG Asia Mater. 15, 1–28 (2023).
Google Scholar
Zhao, W. et al. Origin of indirect optical transitions in few-layer MoS2, WS2, and WSe2. Nano Lett. 13, 5627–5634 (2013).
Google Scholar
Kim, H. & Choi, H. J. Thickness dependence of work function, ionization energy, and electron affinity of Mo and W dichalcogenides from DFT and GW calculations. Phys. Rev. B 103, 085404 (2021).
Google Scholar
Niu, Y. et al. Thickness-dependent differential reflectance spectra of monolayer and few-layer MoS2, MoSe2, WS2 and WSe2. Nanomaterials 8, 725 (2018).
Google Scholar
Chiu, M.-H. et al. Band alignment of 2D transition metal dichalcogenide heterojunctions. Adv. Funct. Mater. 27, 1603756 (2017).
Google Scholar
Jahelka, P. R., Glaudell, R. D. & Atwater, H. A. Systems and methods for non-epitaxial high Schottky-barrier heterojunction solar cells. US Patent 20210391486 (2021).
Kam, K. K. & Parkinson, B. A. Detailed photocurrent spectroscopy of the semiconducting group VIB transition metal dichalcogenides. J. Phys. Chem. 86, 463–467 (1982).
Google Scholar
Keyshar, K. et al. Experimental determination of the ionization energies of MoSe2, WS2, and MoS2 on SiO2 using photoemission electron microscopy. ACS Nano. 11, 8223–8230 (2017).
Google Scholar
Stolterfoht, M. et al. The impact of energy alignment and interfacial recombination on the internal and external open-circuit voltage of perovskite solar cells. Energy Environ. Sci. 12, 2778–2788 (2019).
Google Scholar
Tress, W., Leo, K. & Riede, M. Influence of hole-transport layers and donor materials on open-circuit voltage and shape of I-V curves of organic solar cells. Adv. Funct. Mater. 21, 2140–2149 (2011).
Google Scholar
Tress, W. et al. Imbalanced mobilities causing S-shaped IV curves in planar heterojunction organic solar cells. Appl. Phys. Lett. 98, 063301 (2011).
Google Scholar
Massicotte, M. et al. Picosecond photoresponse in van der Waals heterostructures. Nat. Nanotechnol. 11, 42–46 (2016).
Google Scholar
Bullock, J. et al. Efficient silicon solar cells with dopant-free asymmetric heterocontacts. Nat. Energy 1, 1–7 (2016).
Google Scholar
Cui, Q., Ceballos, F., Kumar, N. & Zhao, H. Transient absorption microscopy of monolayer and bulk WSe2. ACS Nano 8, 2970–2976 (2014).
Google Scholar
Lien, D.-H. et al. Electrical suppression of all nonradiative recombination pathways in monolayer semiconductors. Science 364, 468–471 (2019).
Google Scholar
Wang, H., Zhang, C. & Rana, F. Surface recombination limited lifetimes of photoexcited carriers in few-layer transition metal dichalcogenide MoS2. Nano Lett. 15, 8204–8210 (2015).
Google Scholar
Liu, Y., Hu, X., Wang, T. & Liu, D. Reduced binding energy and layer-dependent exciton dynamics in monolayer and multilayer WS2. ACS Nano. 13, 14416–14425 (2019).
Google Scholar
Yuan, L. & Huang, L. Exciton dynamics and annihilation in WS2 2D semiconductors. Nanoscale 7, 7402–7408 (2015).
Google Scholar
Park, J.-K. et al. Diffusion length in nanoporous photoelectrodes of dye-sensitized solar cells under operating conditions measured by photocurrent microscopy. J. Phys. Chem. Lett. 3, 3632–3638 (2012).
Google Scholar
Wang, H. et al. Radiative lifetimes of excitons and trions in monolayers of the metal dichalcogenide MoS2. Phys. Rev. B. 93, 045407 (2016).
Google Scholar
Jariwala, D., Sangwan, V. K., Lauhon, L. J., Marks, T. J. & Hersam, M. C. Emerging device applications for semiconducting two-dimensional transition metal dichalcogenides. ACS Nano. 8, 1102–1120 (2014).
Google Scholar
High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals. Nat. Commun. 3, 1011 (2012).
Fivaz, R. & Mooser, E. Mobility of charge carriers in semiconducting layer structures. Phys. Rev. 163, 743–755 (1967).
Google Scholar
Ruoff, R. S., Tse, D. S., Malhotra, R. & Lorents, D. C. Solubility of fullerene (C60) in a variety of solvents. J. Phys. Chem. 97, 3379–3383 (1993).
Google Scholar
Byrnes, S. J. Multilayer optical calculations. Preprint at http://arxiv.org/abs/1603.02720 (2020).
Li, Y. et al. Measurement of the optical dielectric function of monolayer transition-metal dichalcogenides: MoS2, MoSe2, WS2, and WSe2. Phys. Rev. B 90, 205422 (2014).
Google Scholar
van Roosbroeck, W. & Shockley, W. Photon-radiative recombination of electrons and holes in germanium. Phys. Rev. 94, 1558–1560 (1954).
Google Scholar
McPeak, K. M. et al. Plasmonic films can easily be better: rules and recipes. ACS Photonics 2, 326–333 (2015).
Google Scholar
Santbergen, R. et al. Minimizing optical losses in monolithic perovskite/c-Si tandem solar cells with a flat top cell. Opt. Express 24, A1288 (2016).
Google Scholar
Scientific, H. An Ellipsometric Study of the Optical Constants of C60 & C70 Thin Films. https://static.horiba.com/fileadmin/Horiba/Application/Materials/Material_Research/Graphene/C60_and_C70_Optical_Constants_Study_by_Ellipsometry.pdf.
Liu, Z. T. et al. The characterization of the optical functions of BCP and CBP thin films by spectroscopic ellipsometry. Synth. Met. 150, 159–163 (2005).
Google Scholar
Lee, Y. et al. Boosting quantum yields in two-dimensional semiconductors via proximal metal plates. Nat. Commun. 12, 7095 (2021).
Google Scholar
Grundmann, M. The Physics of Semiconductors: An Introduction Including Nanophysics and Applications (Springer International Publishing, 2016).
Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS 2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).
Google Scholar
Cho, K., Pak, J., Chung, S. & Lee, T. Recent advances in interface engineering of transition-metal dichalcogenides with organic molecules and polymers. ACS Nano 13, 9713–9734 (2019).
Google Scholar
Rueda-Delgado, D. et al. Solution-processed and evaporated C60 interlayers for improved charge transport in perovskite photovoltaics. Organic Electronics 77, 105526 (2020).
Google Scholar
Lee, K.-M. et al. Thickness effects of thermally evaporated C60 thin films on regular-type CH3NH3PbI3 based solar cells. Sol. Energy Mater. Sol. Cells 164, 13–18 (2017).
Google Scholar
Lee, K. et al. Meter-scale van der Waals films manufactured via one-step roll printing. Sci. Adv. 10, eadq0655 (2024).
Google Scholar
Amani, M. et al. High luminescence efficiency in MoS2 grown by chemical vapor deposition. ACS Nano 10, 6535–6541 (2016).
Google Scholar
Backes, C. et al. Guidelines for exfoliation, characterization and processing of layered materials produced by liquid exfoliation. Chem. Mater. 29, 243–255 (2017).
Google Scholar
Hu, C.-X., Shin, Y., Read, O. & Casiraghi, C. Dispersant-assisted liquid-phase exfoliation of 2D materials beyond graphene. Nanoscale 13, 460–484 (2021).
Google Scholar
Liu, F. Mechanical exfoliation of large area 2D materials from vdW crystals. Prog. Surf. Sci. 96, 100626 (2021).
Google Scholar
Allen, T. G., Bullock, J., Yang, X., Javey, A. & De Wolf, S. Passivating contacts for crystalline silicon solar cells. Nat. Energy 4, 914–928 (2019).
Google Scholar
Dänekamp, B. et al. Influence of hole transport material ionization energy on the performance of perovskite solar cells. J. Mater. Chem. C 7, 523–527 (2019).
Google Scholar
Hirose, Y. Structural and electronic properties of an organic/inorganic semiconductor interface: PTCDA/GaAs(100). J. Vac. Sci. Technol. B Microelectron. Nanom. Struct. 12, 2616 (1994).
Google Scholar
Weerasinghe, H. C. et al. The first demonstration of entirely roll-to-roll fabricated perovskite solar cell modules under ambient room conditions. Nat. Commun. 15, 1656 (2024).
Google Scholar
Novotny, L. & Hecht, B. Principles of Nano-Optics (Cambridge University Press, Cambridge, 2012).
Yoshida, H. et al. Low-energy inverse photoemission study on the electron affinities of fullerene derivatives for organic photovoltaic cells. J. Phys. Chem. C. 118, 24377–24382 (2014).
Google Scholar
Guan, Z.-L. et al. Direct determination of the electronic structure of the poly(3-hexylthiophene):phenyl-[6,6]-C61 butyric acid methyl ester blend. Org. Electron. 11, 1779–1785 (2010).
Google Scholar
Magomedov, A. et al. Self-assembled hole transporting monolayer for highly efficient perovskite solar cells. Adv. Energy Mater. 8, 1801892 (2018).
Google Scholar
Download references
We gratefully acknowledge the critical support and infrastructure provided for this work by The Kavli Nanoscience Institute at Caltech. We acknowledge support from Professor George Rossman’s lab at Caltech. We acknowledge Dr. Ruzan Sokhoyan, Kristina Malinowski, Nimisha Ramprasad, Susana Torres-Londono, and Miles Johnson for discussions and technical support. This work was supported by the Caltech Space Solar Power Project (SSPP) and DOE “Photonics at Thermodynamic Limits” Energy Frontier Research Center under grant DE-SC0019140, which supported the sample fabrication, experimental measurements, data analysis, and simulations. C.M.W., R.W.T., and J.W. acknowledge support from the NSF Graduate Research Fellowship under Grant No. 1745301, 2139433, and 1144469. C.M.W. acknowledges fellowship support from the Resnick Sustainability Institute.
These authors contributed equally: Cora M. Went, Rachel W. Tham.
Department of Physics, California Institute of Technology, Pasadena, CA, USA
Cora M. Went
Resnick Sustainability Institute, California Institute of Technology, Pasadena, CA, USA
Cora M. Went
Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA, USA
Rachel W. Tham, Phillip R. Jahelka, Joeson Wong, Morgaine Mandigo-Stoba & Harry A. Atwater
Department of Chemistry, University of Chicago, Chicago, IL, USA
Joeson Wong
Department of Physics, University of California Los Angeles, Los Angeles, CA, USA
Morgaine Mandigo-Stoba
PubMed Google Scholar
PubMed Google Scholar
PubMed Google Scholar
PubMed Google Scholar
PubMed Google Scholar
PubMed Google Scholar
C.M.W. and R.W.T. contributed equally. C.M.W. fabricated the solar cell devices and conducted experimental measurements, in addition to performing Sentaurus device simulations, data calculations, and figure development. R.W.T. performed equation derivations, Lumerical and Sentaurus device simulations, data calculations and interpretation, figure development, and experimental measurements. C.M.W. and R.W.T. wrote the manuscript with input from J.W., P.R.J., and H.A.A. P.R.J. assisted with selective contact fabrication and photoconductivity measurements. J.W. performed data interpretation and equation derivations. M.M. assisted with experiments on selective contact selection and fabrication. H.A.A. supervised the project. All authors contributed to the results discussion and interpretation, in addition to manuscript preparation.
Correspondence to Harry A. Atwater.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Reprints and permissions
Went, C.M., Tham, R.W., Jahelka, P.R. et al. Dual carrier-selective contact transition metal dichalcogenide solar cells. npj 2D Mater Appl (2026). https://doi.org/10.1038/s41699-026-00684-3
Download citation
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41699-026-00684-3
Anyone you share the following link with will be able to read this content:
Sorry, a shareable link is not currently available for this article.
Provided by the Springer Nature SharedIt content-sharing initiative
Advertisement
npj 2D Materials and Applications (npj 2D Mater Appl)
ISSN 2397-7132 (online)
© 2026 Springer Nature Limited
Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.
