Fig. 3: Multiple cycles straining-relaxing and load-unload bending test.
From: Efficient strain modulation of 2D materials via polymer encapsulation
a, b The multiple cycles straining and relaxing at fixed tension strain of 1.28%, for devices fabricated by our PVA encapsulation method (a) and the conventional exfoliating approach (b). Within spin-coated PVA approach (a), the PL spectrums demonstrate repeatable peak position under multiple cycles test, suggesting the negligible slippage and efficient strain transfer. In contrast, within conventional exfoliating approach (b), the PL spectrums demonstrate a much smaller ΔEg and a gradual blue shift with increasing bending cycles, indicating the poor strain transfer and a significant slippage behavior. c, d The load-unload bending test under variable tension strain level, for our PVA encapsulation method (c) and the conventional exfoliating approach (d). Within spin-coated PVA approach (c), the PL spectrums demonstrate repeatable peak position change, further confirming the negligible slippage and efficient strain transfer. In contrast, within conventional exfoliating approach (d), the PL spectrums demonstrate much smaller modulation efficiency and blue shift of peak position during unloading process, indicating that the poor strain transfer and a significant slippage behavior.
