Are solution processed CsPbI3 perovskite nanocrystalline films similar to traditional crystalline semiconductors?

Abstract

We use ultrafast photocurrent spectroscopy with a sub-25 picosecond resolution to address a long-standing question in emergent perovskite materials: are solution-processed CsPbI3 perovskites nanocrystal films similar to their counterparts semiconductors including GaAs and Si? Prior to carrier trapping, all semiconductors show similar transition of transport mechanism from the band-like transport due to the longitudinal optical (LO) phonon scattering in the higher temperature region to a combination of band-like and hopping transport mechanisms in the lower temperature region. The critical difference is that CsPbI3 demonstrate the strongest carrier-LO phonon interaction among all semiconductors, most likely due to the unique cation-halogen bond arrangements within the highly symmetric lattice structure. This ultrafast dynamics work establish a foundation of fundamental carrier transport understating for perovskite optoelectronics.

In-depth understanding the temperature-dependent reversible phase transition in CsPbI3−xBrx perovskites and its associated photophysical properties

“…The tted coef-cient b value indicates the strength of the carrier-phonon coupling. 61 The b values in the range of −1.12 ∼ −1.56 indicate that the phonon scattering dominates the carrier mobility in the entire temperature range (Fig. 5f), which is consistent with the physical mechanism in which the inuence of impurity scattering is only shown at very low temperatures.…”

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“…[174] Interestingly, very recent work by Gao and colleagues shows that CsPbI 3 PQDs exhibit the strongest carrier-longitudinal optical phonon interaction among all traditional semiconductors. [175] Lastly, it is known that the efficiency of the emerging perovskite solar cells is typically limited by the nonradiative recombination that occurs at the interface between absorber and charge transport layer. [176] However, Wieliczka et al recently reported that the interfaces between the PQD absorber and the charge transport layers have no signi ficant impact on recombination losses, and the free charge carrier concentration of PQDs is orders of magnitude higher than that of perovskite thin films.…”

“…[ 174 ] Interestingly, very recent work by Gao and colleagues shows that CsPbI 3 PQDs exhibit the strongest carrier‐longitudinal optical phonon interaction among all traditional semiconductors. [ 175 ] Lastly, it is known that the efficiency of the emerging perovskite solar cells is typically limited by the nonradiative recombination that occurs at the interface between absorber and charge transport layer. [ 176 ] However, Wieliczka et al.…”