A novel strategy for enhancing thermoelectric performance in organic small-molecule systems is demonstrated through the precise engineering of nanoscale interfacial architecture. By leveraging a vapor-solid reaction between copper phthalocyanine (CuPc) and iodine, a series of CuPc/CuPcI composites were fabricated with tunable phase compositions. The key innovation lies in the controlled formation of a high density of nanoscale interfaces between the CuPc and CuPcI phases, which are not merely physical boundaries but active sites for modulating charge and heat transport. High-resolution transmission electron microscopy (HR-TEM) reveals that these interfaces exhibit structural disorder, including vacancies and lattice distortions, indicating intrinsic interfacial defects that serve as effective phonon scattering centers.
The electrical conductivity increases sharply above a percolation threshold (~23 vol% CuPcI), consistent with a three-dimensional conductive network forming within the composite. However, the Seebeck coefficient remains significantly elevated—reaching 65.3 V K⁻¹—well beyond theoretical predictions based on simple percolation models. This enhancement is attributed to surface polarization at the heterogeneous interfaces: the high dielectric constant of CuPc relative to CuPcI generates built-in electric fields under temperature gradients, promoting additional charge carrier diffusion and boosting the thermopower without sacrificing conductivity.PNMA3 Antibody Autophagy This phenomenon effectively decouples the trade-off between Seebeck coefficient and electrical conductivity, a longstanding challenge in thermoelectrics.
Thermal conductivity measurements reveal a dramatic reduction in lattice thermal conductivity due to enhanced phonon scattering at the abundant nanointerfaces. The contribution from interfacial phonon scattering dominates over point defect scattering, increasing systematically with CuPcI content. Quantitative analysis based on grain boundary area estimation confirms that the total interface area grows with higher CuPcI content, leading to maximum suppression of heat transfer in samples with 95 wt% CuPcI. Furthermore, the presence of interfacial defects softens the crystal lattice, reducing both longitudinal and transverse sound velocities—further suppressing thermal conduction.M-CSF Antibody Cancer
The combined effect results in a peak ZT value of 3.PMID:35231560 0 × 10⁻² at room temperature, among the highest reported for small-molecule charge-transfer complexes. This performance surpasses conventional composite rules and highlights the power of interfacial engineering in organic thermoelectrics. The work establishes a design principle where nanoscale phase separation is not just a structural feature but a functional tool to simultaneously optimize electrical and thermal transport. This approach opens new avenues for developing next-generation organic thermoelectrics with tailored interfacial architectures for energy harvesting applications.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com