Ferroelectric barium titanate microspheres with superior light-scattering ability for the performance enhancements of flexible polymer dye sensitized solar cells and photodetectors

Abstract

In this study, barium titanate microspheres (BTMS) comprising 10 to 20 nm thick one-dimensional (1D) nanorods have been synthesized via a dual-stage hydrothermal process and used as photoelectrode material for the fabrications of high-performance flexible dye sensitized solar cells (FDSSCs) and photodetectors. Crystal structure and morphological analyses have indicated a rutile phase TiO2 microspheres (RTMS) intermediate is transformed as tetragonal BTMS during the hydrothermal process. Because of the superior light-scattering ability and reduced charge recombination at the BTMS/TiO2 nanoparticles film/electrolyte interface by the ferroelectric dipoles of BaTiO3, BTMS/TiO2 nanocomposite based FDSSC photoanode has demonstrated ~1.7-fold higher power conversion efficiency (PCE = 4.53%) than the pure anatase TiO2 nanoparticles based FDSSC photoanode (PCE = 2.66%). A high dielectric permittivity (ɛr = 3114 at 25 °C) and tangent loss (ɛ˝) obtained for the BTMS at low AC frequencies have confirmed their superior dielectric and ferroelectric characteristics over RTMS (ɛr = 888 at 25 °C), created by the strain induced ferroelectric polarization of 1D BaTiO3 nanorods. Similarly, the BTMS coated PET based flexible photodetector has produced quantum efficiency (QE) of 1.1% with an excellent photoresponse, which further indicated the ferroelectric polarization aided photocurrent generation in the BTMS based photoactive materials.