Trimethylsilyl Iodine-Mediated Synthesis of Highly Bright Red-Emitting CsPbI3 Perovskite Quantum Dots with Significantly Improved Stability

Abstract

Herein, we report highly bright and stable CsPbI3 (CPI) perovskite quantum dots (PQDs) synthesized with trimethylsilyl iodine (TMSI) under a reaction circumstance with the I/Pb molar ratio of ∼4.2. The obtained CPI (TMSI-CPI) PQDs show near-unity photoluminescence quantum yields (PLQYs) in solution and high stability (only 9% loss in PLQY after 105 day storage) under ambient and dark conditions. The thermal stability of TMSI-CPI PQDs is also improved: the degradation temperature is higher than that of traditional hot-injection-synthesized CPI (Tra-CPI) PQDs. X-ray photoelectron spectroscopy results show that the TMSI-CPI PQDs have a highly iodine-rich surface (the I/Pb atomic ratio is up to 4.4), which is believed to be responsible for such high stability and PLQYs. Further, the size and surface properties of CPI PQDs can be easily adjusted by changing the amount of TMSI. Finally, we fabricated QDs-based light-emitting diodes (QLEDs) utilizing TMSI-CPI PQDs as an emissive layer showing a maximum luminance...