Figure 3: Photon energy dependence of the photostriction.
From: Giant photostriction in organic–inorganic lead halide perovskites
(a) When the photon energy is close to or above the band gap (that is, 460, 650 and 808 nm lasers), large current on illumination (under 1 V voltage) is observed, whereas negligible photocurrent is obtained when photon energy is below the band gap (that is, 980 nm laser). (b) The photostriction shows similar behaviour to that of photocurrent. (c) Photocurrents and height changes of the single crystal as functions of the incident photon energy, showing clear correlation between these two properties. The light intensity was kept at ∼100 mW cm−2 for all lasers. The black solid line serves as a guide to the eye.
