Enhancing Efficiency and Stability of CsPbI3 Perovskite Quantum Dots Through Co2+-Doping

Inorganic CsPbI₃ quantum dots (QDs) have emerged as a promising material for optoelectronic applications, especially in photovoltaics and light-emitting diodes (LEDs), due to their superior photoluminescence quantum yield (PLQY) and high defect tolerance. However, their inherent instability under environmental factors such as light, heat, and moisture remains a critical challenge. To address this, we explored the doping of CsPbI₃ QDs with Co²⁺ ions via CoI₂ and CoCl₂ sources. The dual role of iodide (I⁻) and chloride (Cl⁻) ions from the dopants in a mixed doped sample effectively filled iodide vacancies and reduced nonradiative recombination, significantly enhancing the PLQY from 85 % to near 99%. Additionally, the stability of these QDs was improved, maintaining their structural integrity under UV light exposure for over two months. Our research, supported by findings from the doped CsPbI₃ QDs, underscores the potential of Co²⁺ doping to improve both the efficiency and longevity of CsPbI₃-based devices, positioning them as strong candidates for advanced optoelectronic applications.