2d Allotrope Of Carbon For Self-Powered, Flexible, And Transparent Optoelectronics

Flexible and transparent optoelectronics based on 2D materials are promising candidates for next-generation technologies. Among all 2D materials, it is of numerous practical implications to explore nonmetal, earth-abundant candidates. Herein, an exciting addition is unearthed-2D hydrogenized amorphous carbon (alpha-C:H). The 2D alpha-C:H nanosheets, with layered structural feature, are composed of crystalline sp(2) nanoclusters embedded in sp(3) amorphous matrix. The typical "vapor-solid" mechanism governs the growth of these nanosheets under the temperature-pressure combination above the Berman-Simon line. Their high transmittance over 97.7% covers the 425-1300 nm wavelength region. Optical characterizations also reveal a spectral overlap between the pi-pi* absorption edge and sigma-sigma* photoluminescence peak. Self-powered and flexible photodetectors based on the 2D alpha-C:H/ZnO heterostructure exhibit a remarkable photoresponse, with a broadened photosensitivity responsivity of 195.16 mA W-1 and a 267-fold decrease of the rise time. This performance enhancement originates from the type II band alignment, the pyroelectric and piezo-phototronic effects. As a new member in the 2D family, alpha-C:H nanosheets promise to be appealing in transparent flexible optoelectronics with ultralow power consumption and real-time, on-site response.