Two regimes of carrier diffusion in vapor-deposited lead-halide perovskites

Patrik Ščajev, Ramunas Aleksiejunas, Saulius Miasojedovas, Saulius Nargelas, Munetomo Inoue, Chuanjiang Qin, Toshinori Matsushima, Chihaya Adachi, Saulius Juršenas

研究成果: ジャーナルへの寄稿学術誌査読

31 被引用数 (Scopus)


Metal halide perovskites are attractive materials for the realization of cheap and effective solar cells, thin film transistors, and light emitters. Carrier diffusion at high excitations, however, is poorly addressed in perovskites, even though it governs the diffusion length and determines the efficiency of photonic devices. To fully understand the dependence of diffusion length on carrier density, we performed direct and independent measurements of the carrier diffusion coefficient and recombination rate in several methylammonium leadhalide perovskite layers by applying the light-induced transient grating technique. We demonstrate the existence of two distinct carrier diffusion regimes within the density range of 1018-1020 cm-3. In the perovskite films of high compositional quality, diffusion is governed by a bandlike transport of free carriers. The diffusivity is high (0.28-0.7 cm2/s) in these samples, even at low carrier density, and further increases with excitation due to carrier degeneracy. The opposite scenario was observed in disordered perovskite layers, where diffusion is governed by hopping-like transport of localized carriers. The diffusion coefficient in latter layers is small (0.01-0.04 cm2/s at low densities) and increases with excitation due to local state filling and carrier delocalization. We show that carrier recombination can be well-described using the nonlinear radiative and nonradiative recombination coefficients that saturate with excitation due to phase space filling at high carrier densities. On the basis of these findings, we provide recommendations for the maximization of carrier diffusion length in different perovskites.

ジャーナルJournal of Physical Chemistry C
出版ステータス出版済み - 10月 5 2017

!!!All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • エネルギー(全般)
  • 物理化学および理論化学
  • 表面、皮膜および薄膜


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