First-principles calculation of bulk photovoltaic effect in CH$_3$NH$_3$PbI$_3$ and CH$_3$NH$_3$PbI$_{3-x}$Cl$_{x}$

Fan Zheng; Hiroyuki Takenaka; Fenggong Wang; Nathan Z. Koocher; Andrew M. Rappe

paper

First-principles calculation of bulk photovoltaic effect in CH $_{3}$ NH $_{3}$ PbI $_{3}$ and CH $_{3}$ NH $_{3}$ PbI $_{3 - x}$ Cl $_{x}$

arXiv:1410.3389

Abstract

Hybrid halide perovskites exhibit nearly 20% power conversion efficiency, but the origin of their high efficiency is still unknown. Here, we compute the shift current, a dominant mechanism of bulk photovoltaic (PV) effect for ferroelectric photovoltaics, in CH $_{3}$ NH $_{3}$ PbI $_{3}$ and CH $_{3}$ NH $_{3}$ PbI $_{3 - x}$ Cl $_{x}$ from first principles. We find that these materials give approximately three times larger shift current PV response to near-IR and visible light than the prototypical ferroelectric photovoltaic BiFeO $_{3}$ . The molecular orientations of CH $_{3}$ NH $_{3}^{+}$ can strongly affect the corresponding PbI $_{3}$ inorganic frame so as to alter the magnitude of the shift current response. Specifically, configurations with dipole moments aligned in parallel distort the inorganic PbI $_{3}$ frame more significantly than configurations with near net zero dipole, yielding a larger shift current response. Furthermore, we explore the effect of Cl substitution on shift current, and find that Cl substitution at the equatorial site induces a larger response than does substitution at the apical site.

First-principles calculation of bulk photovoltaic effect in CH3​NH3​PbI3​ and CH3​NH3​PbI3−x​Clx​

Abstract

First-principles calculation of bulk photovoltaic effect in CH $_{3}$ NH $_{3}$ PbI $_{3}$ and CH $_{3}$ NH $_{3}$ PbI $_{3 - x}$ Cl $_{x}$