Theoretical approach of the electroluminescence quenching in (polymer-CdSe quantum dot) nanocomposite

• The electroluminescence quenching in (polymers-quantum dots) nanocomposite has been investigated theoretically.
• The maximum of exciton density and diffusion length in the device have been estimated.
• The advantage of incorporating optimal concentration and optimal Qds shell thickness of CdSe Qds in the emissive layer has been discussed.

A theoretical approach based on the rate equation of exciton density for the electroluminescence quenching in (polymers-quantum dots) nanocomposite is developed. It is shown that the light intensity observed in the nanocomposite depends respectively on the quantum dots concentration, the injected charge carriers, the exciton density, and the Förster energy transfer between polymer and quantum dots. We have found that the significant reduction of the light intensity is related to the exciton density profiles which exhibit a monotonic decrease with the increase of Förster transfer mechanism. Our theoretical approach for the electroluminescence agrees with experimental results observed in hybrid structure (MEH-PPV) with CdSe quantum dots. The maximum of exciton density is also estimated and we have obtained a value for the exciton diffusion length of 10 nm which is consistent with the available experimental results.

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