Peculiarities of the bulk photovoltaic effect in LiH3(SeO3)2 ferroelectric crystals

• Published in: Optical materials 2024-05, Vol.151, p.115347, Article 115347
• Main Authors: Kapustianyk, Volodymyr, Eliyashevskyy, Yuriy, Vira, Olena, Turko, Borys, Czapla, Zbigniew
• Format: Article
• Language: English
• Subjects: Domain walls; Ferroelectrics; Photovoltaic effect; Protonic conductivity
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2024.115347

LiH3(SeO3)2 ferroelectric crystal exposed to UV light radiation has been found to demonstrate specific photoelectric properties with the significant protonic conductivity outweighed the bulk photovoltaic effect (BPVE). It was shown that the protonic conductivity can be mostly compensated by several cycles of reversal of the applied electric field. As a result, a noticeable photovoltaic response was detected along all main crystallographic directions. The largest power conversion efficiency was observed at the measurements performed along the ferroelectric direction. Its value was found to be increased with excitation light energy approaching the crystal bandgap width. While remaining well below the bandgap of 5.12 eV, the 285 nm and 365 nm excitations can be still considered favorable to study the photoelectric response due to the spread of the photocarrier generation process over the entire volume of the sample. In this case, the broadening of the absorption edge due to the pronounced exciton-phonon interaction, characteristic of the ferroics with hydrogen bonds, is proposed as the dominant mechanism. The higher values of the PV effect parameters observed under the influence of UV light illumination with the wavelength of 285 nm in comparison with 365 nm were explained by a higher value of the corresponding absorption coefficient. The obtained results open the way for investigations of the bulk photovoltaic effect in the ferroics with hydrogen bonds including those with an absorption edge located in the UV region of spectrum. •LiH3(SeO3)2 ferroelectric crystal reveals the bulk photovoltaic effect under UV light radiation.•The bulk photovoltaic effect is observed under the exciting light with a subthreshold value of energy in respect to the bandgap width.•The protonic conductivity overlaps with the bulk photovoltaic effect in LiH3(SeO3)2 ferroelectric crystal.•The largest value of the power conversion efficiency was detected along the ferroelectric direction.