* Question
| What is the adjustment method for the emission wavelength of polymer OLED devices? |
* Answer
| (1) Group adjustment. A certain substituent is introduced on the conjugated chain of the polymer. When the substituent affects the degree of conjugation of the main chain due to its space effect or electron effect, the forbidden bandwidth of the polymer will change. (2) Adjusting the length of the conjugated chain. Changing the conjugation length of the polymer backbone can effectively adjust the emission wavelength of the polymer. The short conjugate produces blue radiation and the long conjugate produces red radiation. (3) Doping adjustment. Doping adjustment is to mix small organic molecules with different emission colors into the polymer, so that the polymer emission layer contains multiple emission centers, and the emission wavelength of the device can be easily adjusted by voltage. This is a very simple and effective method to adjust the emission wavelength. (4) Blending adjustment. Blending adjustment is to mix several polymers with different emission wavelengths as the light-emitting layer of the OLED, and the emission wavelength of the device changes with the applied voltage. |
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