Modulation in charge distribution via polyethylenimine-incorporation into ZnO electron transport layer and its impact on quantum-dots light emitting device stability

Dong Seob Chung; Hany Aziz

doi:10.1117/12.2631581

3 October 2022 Modulation in charge distribution via polyethylenimine-incorporation into ZnO electron transport layer and its impact on quantum-dots light emitting device stability

Dong Seob Chung, Hany Aziz

Author Affiliations +

Proceedings Volume 12208, Organic and Hybrid Light Emitting Materials and Devices XXVI; 1220807 (2022) https://doi.org/10.1117/12.2631581
Event: SPIE Organic Photonics + Electronics, 2022, San Diego, California, United States

Abstract

Polyethylenimine (PEI) is sometimes used as a passivation layer at the interface between ZnO electron transport layer and quantum-dots emission layer in quantum-dots light emitting devices (QDLEDs). We recently find that blending ZnO with PEI (ZnO:PEI) is advantageous over using it in a separate layer in terms of device stability. In this work, a comparative study between the ZnO:PEI with a neat ZnO ETL is conducted. The ZnO:PEI ETL results in improvement in both EQE and lifetime of QDLEDs compared to the ZnO ETL. By replacing the ZnO ETL with the ZnO:PEI ETL, delayed EL measurements reveal changes in charge distribution across the QDLED. Applying a reverse bias pulse shows that the reversible delayed EL components in the QDLED with the ZnO:PEI ETL stemmed from the electrons placed in a hole transport layer (HTL). The electrons in the HTL induce an annihilation of accumulated holes at the QD EML/HTL that can be a cause of device degradation. The result provides a new insight into the importance of managing charge distribution across the QDLED via ZnO ETL modification for realizing highly stable QDLEDs.

Conference Presentation

Citation Download Citation

Dong Seob Chung and Hany Aziz "Modulation in charge distribution via polyethylenimine-incorporation into ZnO electron transport layer and its impact on quantum-dots light emitting device stability", Proc. SPIE 12208, Organic and Hybrid Light Emitting Materials and Devices XXVI, 1220807 (3 October 2022); https://doi.org/10.1117/12.2631581

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