Rational Design of Ferroelectric 2D Perovskite for Improving the Efficiency of Flexible Perovskite Solar Cells Over 23 %

Abstract

Despite the great progress of flexible perovskite solar cells (f-PSCs), it still faces several challenges during the homogeneous fabrication of high-quality perovskite thin films, and overcoming the insufficient exciton dissociation. To the ends, we rationally design the ferroelectric two-dimensional (2D) perovskite based on pyridine heterocyclic ring as the organic interlayer. We uncover that incorporation of the ferroelectric 2D material into 3D perovskite induces an increased builtin electric field (BEF), which enhances the exciton dissociation efficiency in the device. Moreover, the 2D seeds could assist the 3D crystallization by forming more homogeneous and highly-oriented perovskite crystals. As a result, an impressive power conversion efficiency (PCE) over 23 % has been achieved by the f-PSCs with outstanding ambient stability. Moreover, the piezo/ ferroelectric 2D perovskite intrigues a decreased hole transport barriers at the ITO/perovskite interface under tensile stress, which opens new possibilities for developing highly-efficient f-PSCs.

Crystal orientation engineering in two-dimensional perovskites for improved photoelectric properties and applications

“…The addition of 2D perovskites promotes 3D perovskites to undergo the same preferential (110) orientation with better crystallinity. They report elimination of lattice strain in 2D/3D flexible perovskite solar cells (f-PSC) with the highest PCE to date, over 23% [25].…”

Ferroelectricity in Hybrid Perovskites

“…After 1000 cycles of bending, the normalized PCE of the 2D/3D devices stabilized at 93% after about 200 bendings while the control dropped to 50% of the initial PCE. 127 Ji et al reported a broad white-light emitting ferroelectric 2D perovskite, (C 4 H 9 NH 3 ) 2 PbCl 4 , in which the origin of the emission and the ferroelectricity was attributed to the large structural distortion of the PbCl 6 octahedra. The light emission was strongly dependent on the temperature, showing no photoluminescence at 325 K, when the perovskite transitions from the ferroelectric to paraelectric phase.…”