Ultrafast Electron Injection from Photoexcited Perovskite CsPbI 3 QDs into TiO 2 Nanoparticles with Injection Efficiency near 99.

Photoexcited electron injection dynamics from CsPbI ₃ quantum dots (QDs) to wide gap metal oxides are studied by transient absorption spectroscopy. Experimental results show under a low excitation intensity that ∼99% of the photoexcited electrons in CsPbI ₃ QDs can be injected into TiO ₂ with a size-dependent rate ranging from 1.30 × 10 ¹⁰ to 2.10 × 10 ¹⁰ s ^-1 , which is also ∼2.5 times faster than that in the case of ZnO. A demonstration QD-sensitized solar cell based on a CsPbI ₃ /TiO ₂ electrode is fabricated that delivers a power conversion efficiency of 5%.