Polarization‐Modulated Photovoltaic Effect at the Morphotropic Phase Boundary in Ferroelectric Ceramics

Abstract

Ferroelectric materials, which exhibit switchable polarization, are potential candidates for photovoltaic applications owing to their intriguing charge carrier separation mechanism associated with polarization and breaking of inversion symmetry. To overcome the low photocurrent of ferroelectrics, extensive efforts have focused on reducing their bandgaps to increase the optical absorption of the solar spectrum and thus the power conversion efficiency. Here, a new avenue of enhancing photovoltaic performance via engineering the polarization across a morphotropic phase boundary (MPB) is reported. Tetragonal compositions in the vicinity of the MPB in a PbTiO3‐Bi(Ni1/2Ti1/2)O3 solid solution are shown to generate up to 3.6 kV cm−1 photoinduced electric field and 6.2 µA cm−2 short‐circuit photocurrent, multiple times higher than its pseudocubic counterpart under the same illumination conditions with excellent polarization retention. This enhancement allows the investigation of the correlation between the polarization switching and photovoltaic switching, which enables a controllable multistate photocurrent. Combined with a bandgap of 2.2 eV, this material exhibits a sizable photoresponse over a broad spectral range. These findings provide a new approach to improve the photovoltaic performance of ferroelectric materials and can expand their potential applications in optoelectronic devices.

Quantitative investigation of polarization-dependent photocurrent in ferroelectric thin films

“…Figure3shows steady-state short-circuit photocurrent measured at various intermediate poling states in dark and under illumination. A multistate switchable photocurrent can be achieved, like it was reported in PbTiO3-based solid solutions ceramics[20]. These measurements agree well with the I(V) measurements in Figure1giving negative Jsc for Pdown state, positive Jsc for Pup state and a highest Jsc in absolute value for Pdown state.…”

Engineering the Defects and Microstructures in Ferroelectrics for Enhanced/Novel Properties: An Emerging Way to Cope with Energy Crisis and Environmental Pollution

“…Similar highly piezoelectric photoferroelectrics with UV–Vis–NIR light absorption were also reported in other relaxors at MPB compositions, such as (1‐ x )(K 0.48 Na 0.52 )NbO 3‐ x (Bi 0.5 Na 0.5 )(Zr 0.55 Ni 0.45 )O 3‐ δ (KNN‐BNZN), [ 132 ] PbTiO 3 ‐Bi(Ni 2/3 Nb 1/3 )O 3 (PT‐BNN), [ 133 ] PbTiO 3 ‐Bi(Ni 1/2 Ti 1/2 )O 3 . [ 134 ] The photocurrent of the novel photoferroelectrics is an order of magnitude higher compared with PLZT and KNN ceramic or polycrystalline thin films. However, most of the researches are based on ceramics, the large thickness and grain boundary limit the photocurrent.…”

“…[ 119 ] Actually, different photoferroelectrics show different level of photocurrent J sc , from nA cm ‐2 level in KNBNNO [ 35 , 92 ] to µA cm ‐2 level in PbTiO 3 –Bi(Ni 1/2 Ti 1/2 )O 3 . [ 134 ] Therefore, it is necessary to explore new photoferroelectrics with high photoelectric conversion efficiency.…”

A Van Der Waals Photo‐Ferroelectric Synapse

“…[ 43–47 ] In this scenario, one can develop demanded photo‐ferroelectric materials to pursue the design of photo‐ferroelectric synapses. [ 32,48–52 ]…”

“…[43][44][45][46][47] In this scenario, one can develop demanded photo-ferroelectric materials to pursue the design of photo-ferroelectric synapses. [32,[48][49][50][51][52] Here, we present a two-terminal optoelectronic photoferroelectric synapse based on vdW hybrid halide perovskite ((R)-(−)-1-cyclohexylethylammonium)PbI 3 (R-CYHEAPbI 3 ). The photo-ferroelectric synaptic plasticity including long-term memory, endurance, and retention is investigated systematically.…”