Rice researchers lay groundwork for designer hybrid 2D materials

HOUSTON – (May 28, 2025) – Some of the most promising materials for future technologies come in layers just one atom thick ⎯ graphene, e.g., a sheet of carbon atoms arranged in a hexagonal lattice, prized for its exceptional strength and conductivity. While hundreds of such materials exist, truly merging them into something new has remained a challenge. Most efforts simply stack these atom-thin sheets like a deck of cards, but the layers typically lack significant interaction between them.

An international team of researchers led by Rice University materials scientists has succeeded in creating a genuine 2D hybrid by chemically integrating two fundamentally different 2D materials ⎯ graphene and silica glass ⎯ into a single, stable compound called glaphene, according to a study published in Advanced Materials.

“The layers do not just rest on each other ⎯ electrons move and form new interactions and vibration states, giving rise to properties neither material has on its own,” said Sathvik Iyengar, a doctoral student at Rice and a first author on the study.

More importantly, Iyengar explained, the method could apply to a wide range of 2D materials, enabling the development of designer 2D hybrids for next-generation electronics, photonics and quantum devices.

“It opens the door to combining entirely new classes of 2D materials — such as metals with insulators or magnets with semiconductors — to create custom-built materials from the ground up,” Iyengar said.

The team developed a two-step, single-reaction method to grow glaphene using a liquid chemical precursor that contains both silicon and carbon. By tuning oxygen levels during heating, they first grew graphene then shifted conditions to favor the formation of a silica layer. This required a custom high-temperature, low-pressure apparatus designed over several months in collaboration with Anchal Srivastava, a visiting professor from Banaras Hindu University in India.

“That setup was what made the synthesis possible,” Iyengar said. “The resulting material is a true hybrid with new electronic and structural properties.”

Once the material was synthesized, the Rice team worked on confirming its structure with Manoj Tripathi and Alan Dalton at the University of Sussex. One of the first clues that glaphene was something new came from an anomaly. When the team analyzed the material using Raman spectroscopy ⎯ a technique that detects how atoms vibrate by measuring subtle shifts in scattered laser light ⎯ they found signals that did not match either graphene or silica. These unexpected vibrational features hinted at a deeper interaction between the layers.

In most 2D material stacks, the layers simply sit in place, held together weakly like magnets on a fridge door. But in glaphene, the layers lock together through much more than what are called weak van der Waals bonds, allowing electrons to flow between them and giving rise to entirely new behaviors.

To investigate further, Iyengar consulted Marcos Pimenta, an expert in spectroscopy based in Brazil. Ultimately, the anomaly turned out to be an artifact ⎯ an important reminder, Iyengar said, that even reproducible results must be treated with caution.

To better understand how the bonded layers behave at the atomic level, the team collaborated with Vincent Meunier at Pennsylvania State University to verify the experimental results against quantum simulations. These confirmed that the graphene and silica layers interact and bond in a unique way, partially sharing electrons across the interface. This hybrid bonding changes the material’s structure and behavior, turning a metal and an insulator into a new type of semiconductor.

“This was not something only one lab could do,” said Iyengar, who recently spent a year in Japan as a fellow of the Japan Society for the Promotion of Science (JSPS), and also an inaugural recipient of the Quad Fellowship, a program launched by the governments of the U.S., India, Australia and Japan to support early career scientists in exploring how science, policy and diplomacy intersect on the global stage. “This research was a cross-continental effort to create and understand a material nature does not make on its own.”

Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Engineering and professor of materials science and nanoengineering, said that while the discovery of glaphene is significant on its own, what makes the research truly exciting is the broader method it introduces ⎯ a new platform for chemically combining fundamentally different 2D materials.

The research reflects a guiding principle Iyengar says he inherited from his adviser.

“Since I started my Ph.D., my adviser has encouraged me to explore mixing ideas that others hesitate to mix,” he said, quoting Ajayan, who is a corresponding author on the study alongside Meunier. “Professor Ajayan has also said that true innovation happens at the junctions of hesitation ⎯ and this project is proof of that.”

The research was supported by the Quad Fellowship program; the Rice-Penn State collaborative project funded by the Air Force Office of Scientific Research (FA9550-23-1-0447); the National Science Foundation Graduate Research Fellowship Program (2236422); the Sussex Strategy Development Fund; Instituto de Ciência e Tecnologia de Nanomateriais de Carbono; Fundação de Amparo à Pesquisa do Estado de Minas Gerais; and the Brazilian National Council for Scientific and Technological Development. The content herein is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations and institutions.

Iyengar, Srivastava, Meunier and Ajayan express interest in pursuing intellectual property, and a US provisional application on this technology has been filed.

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Peer-reviewed paper:

Glaphene: A hybridization of 2D silica glass and graphene | Advanced Materials | DOI: 10.1002/adma.202419136

Authors: Sathvik Iyengar, Manoj Tripathi, Anchal Srivastava, Abhijit Biswas, Tia Gray, Mauricio Terrones, Alan Dalton, Marcos Pimenta, Robert Vajtai, Vincent Meunier and Pulickel Ajayan

https://doi.org/10.1002/adma.202419136

Video is available at:

https://www.youtube.com/watch?v=3wYwYCnhiAM
Description: Collective vibrational excitation of glaphene ⎯ interactions in glaphene go beyond conventionally observed 2D layer stacks. (Courtesy of Sathvik Iyengar/Rice University)

About Rice:

Located on a 300-acre forested campus in Houston, Texas, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of architecture, business, continuing studies, engineering and computing, humanities, music, natural sciences and social sciences and is home to the Baker Institute for Public Policy. Internationally, the university maintains the Rice Global Paris Center, a hub for innovative collaboration, research and inspired teaching located in the heart of Paris. With 4,776 undergraduates and 4,104 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 7 for best-run colleges by the Princeton Review. Rice is also rated as a best value among private universities by the Wall Street Journal and is included on Forbes’ exclusive list of “New Ivies.”