Ultrafast Electron Injection from Photoexcited Perovskite CsPbI₃ QDs into TiO₂ 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%.