Electronic Properties of Two-Dimensional Penta-Structures

Two-dimensional penta-structures are crystalline sheets or ribbons built from pentagon motifs, often realised in carbon, group III–V and transition-metal compounds. Unlike hexagonal graphene, these pentagonal lattices exhibit intrinsic band gaps, offering semiconducting or metallic behaviour depending on composition and topology. Their mixed sp²/sp³ bonding networks underpin unusual electronic dispersion, including quasi-direct gaps, high carrier mobility and, in some cases, half-metallicity and ferromagnetism. First-principles studies reveal that strain, chemical functionalisation or defect engineering can tune the band gap and even drive semiconductor–metal transitions. Beyond fundamental interest, such tunability underpins potential applications in nano-optoelectronics, piezoelectric generators, spintronics and chemical sensors, highlighting the global significance of pentagonal monolayers for next-generation devices.

Research from Nature Portfolio

Investigations of penta-BP5 monolayers have shown that this boron-phosphide variant forms a stable tetragonal lattice with a quasi-direct band gap of about 2.7 eV. Small uniaxial strain can convert the gap to fully direct, while moderate biaxial strain induces a semiconductor-to-metal transition, demonstrating strain-engineered band-gap control. A tight-binding parametrisation for penta-graphene and its nanoribbons accurately reproduces the ab initio electronic bands and predicts strong, isotropic optical absorption up to 24 % at characteristic energies, thereby enabling rapid modelling of optoelectronic properties in finite geometries. Line-defect engineering in penta-graphene via substitutional nitrogen or silicon atoms has been shown to modulate its electronic character across semiconducting, semimetallic and metallic regimes, illustrating defect design as a versatile route to tailor conductivity.

Electronic Properties of Two-Dimensional Penta-Structures publication trend

The graph below shows the total number of articles in electronic properties of two-dimensional penta-structures across all publications each year (not limited to Nature Index journals).

Technical terms

Band gap: Energy difference between the valence band maximum and the conduction band minimum that determines a material’s electrical conductivity.

Density functional theory: Quantum mechanical framework for computing electronic structure by treating electron density as the central variable.

Tight-binding model: Simplified electronic-structure method in which electrons are assumed to hop between discrete atomic orbitals.

Hybridisation: Mixing of atomic orbitals (for example sp² and sp³) to form new bonding geometries within a crystal lattice.

Piezoelectricity: Property of certain materials to generate electrical polarisation when subjected to mechanical strain.

Shift current: Photovoltaic current arising in noncentrosymmetric materials due to asymmetric carrier excitation under illumination.

References

1. Structures, fundamental properties, and potential applications of low-dimensional C60 polymers and other nanocarbons: a review. Science and Technology of Advanced Materials (2024).
2. Two-dimensional Penta-BP5 Sheets: High-stability, Strain-tunable Electronic Structure and Excellent Mechanical Properties. Scientific Reports (2017).
3. Half-metallicity and ferromagnetism in penta-AlN2 nanostructure. Scientific Reports (2016).
4. Tight-binding model for opto-electronic properties of penta-graphene nanostructures. Scientific Reports (2018).
5. Density Functional Theory Study of B, N, and Si Doped Penta-Graphene as the Potential Gas Sensors for NH3 Detection. Membranes (2022).
6. Screening transition metal-based polar pentagonal monolayers with large piezoelectricity and shift current. npj Computational Materials (2022).
7. Tuning Penta-Graphene Electronic Properties Through Engineered Line Defects. Scientific Reports (2020).