2D Allotrope of Carbon for Self‐Powered, Flexible, and Transparent Optoelectronics

Abstract

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 (α‐C:H). The 2D α‐C:H nanosheets, with layered structural feature, are composed of crystalline sp2 nanoclusters embedded in sp3 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 π–π* absorption edge and σ–σ* photoluminescence peak. Self‐powered and flexible photodetectors based on the 2D α‐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, α‐C:H nanosheets promise to be appealing in transparent flexible optoelectronics with ultralow power consumption and real‐time, on‐site response.

Spin-Current Modulation in Hexagonal Buckled ZnTe and CdTe Monolayers for Self-Powered Flexible-Piezo-Spintronic Devices

“…Recent experiments have demonstrated the effect of piezoelectricity in enhancing performances in nano-electronic devices and led to the concept of self-powered electronics . − Piezoelectric materials convert the mechanical energy into electrical energy, which can be utilized in powering small-scale electronic devices, such as piezoelectric printers, piezoelectric speakers in cell phones, earbuds, sound-producing toys, musical greeting cards, piezoelectric buzzers in various alarms, piezoelectric ignitors, and micro-robotics in defense applications. Hence, the quest for new 2D piezoelectric materials with enhanced transfer efficiency for ultra-thin flexible nano-piezotronics devices is in progress.…”

Zero power infrared sensing in 2D/3D-assembled heterogeneous graphene/In/InSe/Au

“…6 shows the R values of our InSe photodetectors, in comparison with those of other 2D-material-based self-powered photodetectors, at various wavelengths. 14,16,29,32,33,45–57 A p–n junction, doping, and asymmetric contacts were introduced to create built-in potentials in previously reported self-powered photodetectors. Accompanied by such an approach to induce a built-in potential, our vertical heterostructure with transparent FLG/In top contact and bottom Au contact underneath the InSe develops a distinctively large built-in field with a short transit time.…”

Recent Advances in Ferroelectric‐Enhanced Low‐Dimensional Optoelectronic Devices

“…In recent years, studies of self-powered PDs have been increasing rapidly. [129][130][131] FE polarization induced by the spontaneous polarizationinduced electric field (E ferro ) can improve the separation ability of photoexcited electron-hole pairs to realize self-powered photodetection. [132] When an FE material and a semiconductor material are in contact, the concentration of charge carriers at the band edge causes band bending.…”