Polarization-Enhanced Photovoltaic Effects in a High-Temperature Molecular Ferroelectric [C<sub>6</sub>N<sub>2</sub>H<sub>18</sub>][SbI<sub>5</sub>]-Based Solar Device
Ganghua Zhang, Mingjun Zhu, Jiayi Guan, Xinyue Liu, Tao Zeng, Wenge Yang
Abstract
Molecular ferroelectrics with narrow bandgaps has great potential in the photoelectric field, but the outstanding species are still scarce. Herein, [C6N2H18][SbI5] has been demonstrated as a room-temperature (RT) molecular ferroelectric and applied to the organic–inorganic hybrid solar cells as the light-absorbing layer. The polar orthorhombic structure was solved by single-crystal XRD. The inherent RT ferroelectricity was revealed by hysteresis measurements with superior saturation polarization (Ps), remanent polarization (Pr), and coercive field (Ec) as 12.55 μC/cm2, 10.78 μC/cm2, and 0.33 kV/cm, respectively. The [C6N2H18][SbI5]-based solar device exhibits a significant photovoltaic (PV) effect under AM 1.5 G illumination with Voc ∼ 0.43 V, Jsc ∼ 35.17 μA/cm2, and a fast response time of ∼0.33 ms. A dramatical enhancement in PV performance has been achieved by turning the ferroelectric polarization, leading to the maximum Voc ∼ 0.75 V, Jsc ∼ 1.09 mA/cm2, and a power conversion efficiency (PCE) of 0.29%. This work offers a bright avenue for molecular ferroelectrics in optoelectronic devices.