Janus Functionalized Boron‐Nitride Nanosystems as a Potential Application for Absorber Layer in Solar Cells

Abstract

Abstract Janus nanosystems enable one to achieve complementary properties in a single entity. In the current study, the fundamental properties like structural, electronic, and dynamical of Janus hexagonal boron nitride (h‐BN) by selectively hydrogenating and fluorinating a h‐BN surface are systematically examined, using density functional theory. Functionalization of h‐BN introduces partial sp3 (buckled) character in the predicted materials as compared to planar sp2 h‐BNs. Fully fluorinated and hydrogenated h‐BN have a direct bandgap of 3.42 and 3.37 eV, respectively. All the investigated configurations are predicted to be dynamically stable. Furthermore, optical properties including dielectric function, absorption spectra, refractive index, and reflectivity are evaluated to realize the optical and photocatalytic behavior of considered systems. The dielectric function ɛ2(ω) shows fundamental absorption edge arising at 3.2, 3.9, 2.8, and 3.4 eV for hydrogen on boron and nitrogen, hydrogen on boron and fluorine on nitrogen, fluorine on boron and hydrogen on nitrogen (FBNH) and fluorine on boron and nitrogen which is comparable to the bandgap of respective monolayers. Solar cell parameters of all considered BN structures are calculated using the Shockley–Queisser (SQ) limit. The highest short‐circuit current density (Jsc ) for FBNH is found to be 2.1 mA cm−2 providing the efficiency of 8.27% making FBNH a potential candidate for absorber layer in solar cells.

Keywords

• density functional theory
• direct bandgap semiconductors
• Janus functionalization
• phonons
• solar cells