Unveiling Thermoelectric Properties of SURMOF Nanofilms: A New Frontier in Molecular Thermoelectrics

Layer‐by‐layer engineered surface‐mounted metal‐organic framework (SURMOF) nanofilms exhibit enhanced thermoelectric performance through precise control of thickness, molecular alignment, and guest doping. Abstract Molecular thermoelectric materials, which harness molecular‐level design principles to optimize energy conversion, have emerged as a promising strategy for addressing the limitations of bulk inorganic thermoelectrics, such as brittleness and high production costs. In this study, a layer‐by‐layer (LbL) engineered HKUST‐1 surface‐mounted metal‐organic framework (SURMOF) nanofilm is proposed as a promising thermoelectric nanostructure, systematically characterized across its thickness. By employing LbL growth of HKUST‐1 on self‐assembled monolayers (SCnCOOH, n = 2, 10), nanofilms ranging from 5 to 30 nm in thickness are successfully fabricated. Thermoelectric characterization of these nanofilms revealed a significant enhancement in Seebeck coefficient (S) and power factor (PF), with PF values surpassing those of conventional organic SAMs by a factor of 103. Ultraviolet photoelectron spectroscopy (UPS) measurements further confirmed a correlation between molecular orbital alignment and thermoelectric performance, particularly in junctions doped with guest molecules such as ferrocene (Fc) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ). These findings establish SURMOF nanofilms as a viable molecular thermoelectric architecture, offering enhanced carrier transport, guest‐responsive electronic properties, and precise structural control at the nanoscale. Layer-by-layer engineered surface-mounted metal-organic framework (SURMOF) nanofilms exhibit enhanced thermoelectric performance through precise control of thickness, molecular alignment, and guest doping. Abstract Molecular thermoelectric materials, which harness molecular-level design principles to optimize energy conversion, have emerged as a promising strategy for addressing the limitations of bulk inorganic thermoelectrics, such as brittleness and high production costs. In this study, a layer-by-layer (LbL) engineered HKUST-1 surface-mounted metal-organic framework (SURMOF) nanofilm is proposed as a promising thermoelectric nanostructure, systematically characterized across its thickness. By employing LbL growth of HKUST-1 on self-assembled monolayers (SC n COOH, n = 2, 10), nanofilms ranging from 5 to 30 nm in thickness are successfully fabricated. Thermoelectric characterization of these nanofilms revealed a significant enhancement in Seebeck coefficient ( S ) and power factor (PF), with PF values surpassing those of conventional organic SAMs by a factor of 10 3. Ultraviolet photoelectron spectroscopy (UPS) measurements further confirmed a correlation between molecular orbital alignment and thermoelectric performance, particularly in junctions doped with guest molecules such as ferrocene (Fc) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). These findings establish SURMOF nanofilms as a viable molecular thermoelectric architecture, offering enhanced carrier transport, guest-responsive electronic properties, and precise structural control at the nanoscale. Advanced Science, Volume 12, Issue 44, November 27, 2025.