RESUMO
Semiconductors with broadband photoelectric response have important practical needs in many aspects such as solar energy conversion, photocatalysis, and photodetection. We synthesized the first photochromic semiconductive hydrogen-bonded organic framework (HOF), [H2(bpyb)](H2PO4)2·2H2O (1), using the polycyclic viologen cation [H2(bpyb)] (bpyb = 1,4-bis(tetrapyridyl)benzene). After 1 s of xenon lamp irradiation, compound 1 showed a visible color change from the initial yellowish to dark purple after continuous irradiation. The photoinduced radical product has an absorption band covering 200-1700 nm, which is wider than the absorption ranges of silicon and perovskites. It produced photocurrent when irradiated with a xenon lamp or a laser (355, 532, or 808 nm). The on/off ratio of the current (Iirr/Idark) can be as high as 300 times under the irradiation of the 808 nm laser with a power of 1.9 W cm-2. In addition, under the 808 nm light source, the on/off ratio of 1B is 35 times that of 1A.