Fig. 3: Multibit memory behaviors under the broadband lighting.
a, Schematic illustrations of the changes in separation efficiency of electron-hole pairs under different light conditions, where ES,R, ES,U, ES,B, ES,G are separation efficiency of electron-hole pairs excited by light of red, UV, blue, and green, respectively. The purpose is to show visually the effect of light wavelength on the optoelectronic properties. b, Theoretical calculated t-index of the nHOED excited by varying light conditions, which represents the extent of charge separation. c, Representative five memory states of the device stimulated by broadband light within the wavelength range of UV-vis region (0.1 mW cm–2 for 1.5 s, intervals 3.5 s, VD and VG of –0.1 V). d, Multibit memory states programmed by sequential 520 nm light pulses (0.1 mW cm–2 for 1.5 s, intervals 3.5 s, VD and VG of –0.1 V). e, Retention performance of the nHOED after the light program (520 nm, 0.83 mW cm–2 for 30 s, VD = –0.1 V and VG = 0 V) and voltage erase (VG of 1 V for 5 s, VD = –0.1 V) operations, reading at VD = –0.1 V and VG = 0 V. f, Endurance test under 200-program/erase (P/E) cycles: programmed by 520 nm light pulse (0.83 mW cm–2 for 30 s, VD = –0.1 V and VG = 0 V), on-current reading for 20 s at VD = –0.1 V and VG = 0 V, erased by a VG pulse (1 V for 5 s), off-current reading at VD = –0.1 V and VG = 0 V for 10 s.
