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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/CsPbBr 3 composite fiber incorporating orthorhombic CsPbBr 3 (a piezoelectric phase) is fabricated through room-temperature electrospinning. Subsequently, flexible photodetectors (PDs) based on PVDF/CsPbBr 3 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 CsPbBr 3 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 .
Xue et al. (Wed,) studied this question.