Unveiling the Contribution of Piezoelectric and Ferroelectric Effect to Inorganic Halide Perovskites Photodetectors

Compression and tensile strain based on piezo-phototronic effect represent a valid method for modulating the photocurrent of photodetectors. However, the underlying mechanism responsible for the asymmetric increase/decrease of photocurrent under identical compressive/tensile stresses remains unclear. Herein, a PVDF/CsPbBr3 composite fiber incorporating orthorhombic CsPbBr3 (a piezoelectric phase) is fabricated through room-temperature electrospinning. Subsequently, flexible photodetectors (PDs) based on PVDF/CsPbBr3 are constructed to explore the impact of strain on photocurrent. The results reveal a 103% increase in photocurrent under a strain of −0.09% (compressive strain), significantly exceeding the 38% decrease observed under a strain of 0.09% (tensile strain). Furthermore, the piezoelectric and ferroelectric properties of the orthorhombic CsPbBr3 are computed using density functional theory (DFT), confirming that the asymmetric modulation of photocurrent stems from the nature of the piezoelectric effect and ferroelectric effect. Additionally, the ferroelectric effect exerts a more pronounced influence on the photocurrent, which is 2.2 times greater than the piezoelectric effect. This work provides compelling evidence for the piezoelectric and ferroelectric effects of inorganic halide perovskites, underscoring the substantial potential of these effects in optoelectronic devices.