OLED Host Compound Composition for Low-Voltage Stable Emission

The patent modifies the chemical structure of the host material by introducing specific substituents (such as triphen胺 groups, carbazole groups, or dibenzofuran groups) to adjust the energy levels and HOMO-LUMO gaps. This changes the luminescence characteristics and prevents excessive redshift while maintaining high luminous efficiency through optimized energy transfer to the dopant.

The patent employs a carefully designed host/dopant composite system where the host material contains specific functional groups that create optimal intermolecular interactions. The composite structure enables efficient energy transfer from host to dopant while controlling the luminescence wavelength through the specific chemical composition and molecular weight of the host polymer.

The patent increases the molecular weight of the host polymer and introduces rigid aromatic groups (such as triphen胺, carbazole, dibenzofuran) that raise the glass transition temperature and thermal decomposition temperature. This allows the material to withstand Joule heating during operation without crystallizing, even at high luminous efficiencies that generate significant heat.

The patent converts the harmful effect of Joule heating into a beneficial outcome by designing host materials with such high thermal stability that the heat generated during operation actually improves charge transport and exciton formation without causing degradation. The thermal energy facilitates optimal energy transfer to the dopant while the material's high Tg prevents crystallization.

The patent designs a single host polymer material that simultaneously performs multiple functions: it provides the structural matrix, enables charge transport, facilitates energy transfer to the dopant, and controls the luminescence wavelength. This multi-functional host material achieves high luminous efficiency and color purity without requiring complex multi-layer structures.

The host polymer acts as an intermediary that mediates between the injected charges and the dopant molecules. It facilitates charge transport to the dopant sites, enables efficient energy transfer through optimized HOMO-LUMO gap matching, and controls the emission characteristics. This intermediary role allows a simple single-layer structure to achieve high efficiency.