Biaxial strain improving carrier mobility for inorganic perovskite: ab initio Boltzmann transport equation

Abstract

Inorganic halide perovskites have attracted interest due to their high efficiency and low cost. Considering the uncertainty of ex perimental measurements, it was important to predict the upper limit of carrier mobility. In this study, the ab initio Boltzmann transport equation (BTE), including all electron-phonon interactions, was used to accurately predict the mobilities of CsPbI3, CsSnI3, CsPbBr3, and CsSnBr3. Using the iterative Boltzmann transport equation (IBTE), the calculated mobility for CsPbI3 is µe=512/µh=379 cm2V −1 s −1 , and Sn-based perovskite exhibited high hole mobility. The longitudinal optical phonons associated with the stretching between halogen anions and divalent metal cations were revealed to be the dominant scattering source for the carriers. Furthermore, the effect of biaxial strain on mobility was investigated. We observed that biaxial compressive strain could improve the mobility of CsPbI3 and CsPbBr3. Surprisingly, under a compressive strain of -2%, the mobilities of CsPbI3 using IBTE approach were improved to µe=1176/µh=936 cm2V −1 s −1 . It was revealed that the compressive strain could decrease the effective mass of CsPbI3 and CsPbBr3.

Search for simple β-AIMIIIO2-type intrinsic ferroelectric semiconductors with simultaneous robust built-in electric field and full-spectrum absorption for superior photocatalysts

“…The calculations showed that the electron mobility of these four β-AMO 2 candidate IFSs was in the range of 9 × 10 3 to 3.7 × 10 5 cm s −1 V −1 and the hole mobility was up to 1.7 × 10 3 cm s −1 V −1 compared with other types of photocatalysts, such as inorganic chalcogenides (9 × 10 2 –10 3 cm s −1 V −1 ), 82 inorganic–organic chalcogenides (7–30 × 10 3 cm s −1 V −1 ), 83 and heterojunction structures (104 cm s −1 V −1 ), 84 indicating the excellent catalytic performance of these ferroelectric photocatalysts.…”

High-throughput screening of the transport behavior of tetragonal perovskites

“…The mechanical behavior of these perovskites was mainly determined by the interaction between B-site cations and halogen anions. 49,64 Due to electronegativity and ionic radius, the bond characteristics between group II and halogen were different from those between group IV and halogen. In the xy plane, the bond angle was 160.7° for Cl–Sn–Cl, 153.9° for Cl–Sr–Cl, 173.9° for Cl–Ca–Cl, 179.9° for Cl–Mg–Cl and Br–Mg–Br, and 168.2° for I–Mg−I, respectively.…”

“…It satisfied J e, α = neμ e, αβ E β , where n denotes the number of electrons per unit volume and μ e denotes the carrier mobility. If the current density satisfied a linear response under the action of an electric field, the mobility could be expressed as follows: 36,63,64 Here, the carrier group velocity could be obtained by taking the first derivative of the energy band, expressed as v n k , α = ħ −1 ∂ E n k /∂ k α , where E n k is the carrier energy at n band with a wave vector of k . f n k is the Fermi–Dirac distribution.…”

“…It satisfied J e,a = nem e,ab E b , where n denotes the number of electrons per unit volume and m e denotes the carrier mobility. If the current density satisfied a linear response under the action of an electric field, the mobility could be expressed as follows:36,63,64…”