Modulating the Electron鈥揌ole Interaction in a Hybrid Lead Halide Perovskite with an Electric Field

详细信息    查看全文

• 作者：Tomas Leijtens ; Ajay Ram Srimath Kandada ; Giles E. Eperon ; Giulia Grancini ; Valerio D鈥橧nnocenzo ; James M. Ball ; Samuel D. Stranks ; Henry J. Snaith ; Annamaria Petrozza
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 16, 2015
• 年：2015
• 卷：137
• 期：49
• 页码：15451-15459
• 全文大小：463K
• ISSN：1520-5126

文摘

Despite rapid developments in both photovoltaic and light-emitting device performance, the understanding of the optoelectronic properties of hybrid lead halide perovskites is still incomplete. In particular, the polarizability of the material, the presence of molecular dipoles, and their influence on the dynamics of the photoexcitations remain an open issue to be clarified. Here, we investigate the effect of an applied external electric field on the photoexcited species of CH₃NH₃PbI₃ thin films, both at room temperature and at low temperature, by monitoring the photoluminescence (PL) yield and PL decays. At room temperature we find evidence for electric-field-induced reduction of radiative bimolecular carrier recombination together with motion of charged defects that affects the nonradiative decay rate of the photoexcited species. At low temperature (190 K), we observe a field-induced enhancement of radiative free carrier recombination rates that lasts even after the removal of the field. We assign this to field-induced alignment of the molecular dipoles, which reduces the vibrational freedom of the lattice and the associated local screening and hence results in a stronger electron鈥揾ole interaction.