Survey of Synergistically Doped CsPbI3 Quantum Dots for LED Applications

• Published in: ACS applied nano materials 2024-07, Vol.7 (14), p.16735-16748
• Main Authors: Naziri, Pouriya, Simon, Paul, Onal, Asim, Nizamoglu, Sedat, Aydemir, Umut, Peighambardoust, Naeimeh Sadat
• Format: Article
• Language: English
• ISSN: 2574-0970; 2574-0970
• DOI: 10.1021/acsanm.4c02790

In recent years, colloidal quantum dots (QDs) derived from inorganic halide perovskites have shown great promise in optoelectronic applications. Despite their promising optical properties, the full potential of CsPbI3 QDs is significantly undermined by high surface trap densities and poor environmental stability. To address these challenges, this research focuses on an innovative approach involving synergetic Co2+ doping of CsPbI3 QDs and I–/Cl– ion passivation. Co2+ doping is achieved by utilizing various dopant sources such as CoI2, CoCl2, and mixed CoI2/CoCl2. The anions from CoCl2 and CoI2 occupy iodide vacancies, thereby reducing nonradiative recombination. The optimized composition, CsPb0.95Co0.05I3 QDs with mixed CoI2/CoCl2 doping, exhibits exceptionally low trap density and superior stability. The superior efficacy of mixed doping compared to sole CoCl2 doping suggests the complementary action of I– ions (from CoI2) along with Cl– ions (from CoCl2) in passivating surface defects. Optimized CsPb0.95Co0.05I3 QDs demonstrate a significant boost in photoluminescence (PL) performance and stability, achieving an exceptional 98.86% PL quantum efficiency while maintaining stability for over two months under UV light exposure. Integration of the optimized QDs into LED devices yields an outstanding external quantum efficiency (EQE) of 34.6%, showcasing their promising potential for efficient lighting applications.