OLED Element Light-Induced Charge Transfer

The patent divides the charge transport function into separate components: a light-induced electron transfer material layer and a hole transmission material layer (or electron transmission material layer). This segmentation allows each layer to specialize in specific functions, improving overall carrier concentration and recombination efficiency while maintaining manufacturing simplicity through modular material selection and deposition processes.

The patent employs composite material structures by combining light-induced electron transfer materials (such as benzoylimino, porphyrin, or perylene derivatives) with hole transmission materials or electron transmission materials. This composite approach enables simultaneous optimization of light absorption, charge generation, and charge transport properties, thereby enhancing light-emission brightness and efficiency without complicating the fabrication process.

The light-induced electron transfer material acts as an intermediary between the injected carriers and the light-emitting layer. It absorbs light to generate additional charge carriers (electrons or holes) that are then transmitted to the light-emitting layer. This intermediary mechanism increases carrier concentration and recombination efficiency without requiring a proportional increase in driving voltage, as the light energy itself drives the additional charge generation.

The patent changes the optical and electronic parameters of the charge transport layers by selecting materials with specific light absorption characteristics and charge transfer properties. The light-induced electron transfer materials are chosen for their ability to absorb visible light and generate charges, while the transmission materials are selected for their optimal HOMO/LUMO levels to facilitate charge injection. This parameter optimization allows efficient carrier generation and transport at lower driving voltages.

The light-induced electron transfer material layer serves multiple functions simultaneously: it absorbs light to generate charges, transports generated charges, and interfaces with the light-emitting layer. This multi-functionality reduces the need for separate dedicated layers for each function, thereby improving light-emission efficiency without proportionally increasing structural complexity. The same layer that generates charges also facilitates their transport to the emission zone.

The patent merges the charge generation and charge transport functions into integrated layer structures. The light-induced electron transfer material is combined with hole transmission materials or electron transmission materials to form unified functional layers that perform both charge generation (through light absorption) and charge transport. This merging simplifies the overall device architecture compared to having separate independent layers for each function.