title: Organic nanowire/crystalline silicon p-n heterojunctions for high-sensitivity, broadband photodetectors.
abstract: Organic/inorganic hybrid devices are promising candidates for high-performance, low-cost optoelectronic devices, by virtue of their unique properties. Polycrystalline/amorphous organic films are widely used in hybrid devices, because defects in the films hamper the improvement of device performance. Here, we report the construction of 2,4-bis[4-(N,N-dimethylamino)phenyl]squaraine (SQ) nanowire (NW)/crystalline Si (c-Si) p-n heterojunctions. Thanks to the high crystal quality of the SQ NWs, the heterojunctions exhibit excellent diode characteristics in darkness. It is significant that the heterojunctions have been found to be capable of detecting broadband light with wavelengths spanning from ultraviolet (UV) light, to visible (Vis) light, to near-infrared (NIR) light, because of the complementary spectrum absorption of SQ NWs with Si. The junction is demonstrated to play a core role in enhancing the device performance, in terms of ultrahigh sensitivity, excellent stability, and fast response. The photovoltaic characteristics of the heterojunctions are further investigated, revealing a power conversion efficiency (PCE) of up to 1.17%. This result also proves the potential of the device as self-powered photodetectors operating at zero external bias voltage. This work presents an important advance in constructing single-crystal organic nanostructure/inorganic heterojunctions and will enable future exploration of their applications in broadband photodetectors and solar cells.
authors.affiliation: Institute of Functional Nano & Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Jiangsu, Suzhou 215123, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Jie
authors.forename: Qixun
authors.initials: Q
authors.lastname: Shang
authors.forename: Jincheng
authors.initials: J
authors.lastname: Wang
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Zhang
authors.forename: Shenwen
authors.initials: S
authors.lastname: Yao
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhang
keywords: broadband photodetectors; crystalline silicon; organic nanowires; p−n heterojunctions; solar cells