Study on Influence of AC Poling on Bulk Photovoltaic Effect in Pb(Mg_1/3Nb_2/3)O₃‐PbTiO₃ Single Crystals

Abstract The bulk photovoltaic effect (BPVE) provides a theory of surpassing the Schockley–Queisser limit. However, improving the BPVE efficiency to a level comparable to that of the semiconductor‐based efficiencies is challenging in practice due to conflicting material design requirements. Previous works have shown that a stacked domain structure in a rhombohedral BiFeO 3 ferroelectric epitaxial thin film is able to satisfy the criteria of both a small mean free path for an optimized photocurrent and a large distance between electrodes for an optimized photovoltage. Nevertheless, this hypothesis has remained difficult to verify with other materials due to the complication of domain wall manipulation. This work takes advantage of the recent advances in controlling the domain structure in rhombohedral Pb(Mg 1/3 Nb 2/3 )O 3 ‐PbTiO 3 (PMN‐PT) single crystals via AC poling. By comparing the photovoltage and photocurrent values after domain manipulations in four types of commercial PMN‐PT samples, this work validates the hypothesis of the stacked domain structure enhancing the BPVE by witnessing a simultaneous increase of over 35% for both the open‐circuit voltage and short‐circuit current from DC to the AC‐poled states under a 405 nm laser illumination. This result paves the way for further improving the BPVE efficiency in ferroelectrics.