High-κ Mn-MOF Exhibiting Solvent-Responsive Dielectric Behavior for Gate Dielectric Applications

High-κ dielectrics that offer high permittivity with minimal leakage are essential for advanced electronic devices; however, achieving such performance within porous hybrid materials remains challenging. In this study, we report the Mn-based metal–organic framework, [Mn2(SBA)2(DMSO)2].DMSO (Mn-MOF-D), synthesized via a solvothermal method using Mn(OAc)2 4H2O salt, 4,4ˈ-sulfonyldibenzoic acid (H2SBA), and 5-methyl-2-pyrazinecarboxylic acid (mpyzc) in a mixture of DMSO-H2O. Single-crystal analysis reveals a unique dinuclear {Mn2O10} secondary building unit (SBU) comprising corner-shared distorted octahedral and square pyramidal Mn centers. Dielectric measurements show that Mn-MOF-D is a high-κ material (κ = 40.5 at 1 kHz, 303 K) with a low 6.7 × 10–9 S·cm–1 AC conductivity (5 kHz, 303 K). The metal–insulator–metal (MIM) device fabricated from the material showed minimal leakage with a current density of 2.08 × 10–12 A·cm–2. The high dielectric response arises from dipolar contributions of coordinated and lattice-confined DMSO molecules along with the intrinsic polarizability of the framework. After removal of polar solvents from Mn-MOF-D, the dielectric constant εrˈ(ω) dropped to κ = 16.8 (at 1 kHz, 303 K), underscoring their crucial role in overall dielectric polarization. Impedance and AC conductivity analyses confirm Maxwell–Wagner–type relaxation and thermally activated hopping conduction. The combination of a large dielectric constant, low loss, and excellent framework stability makes this material promising for solvent-tunable high-κ dielectrics in gate dielectric applications.