Printed graphene/WS 2 battery-free wireless photosensor on papers

Park

et al. 2021

Sci Rep

Dual-functional quantum-dots light emitting diodes (QLEDs) have been fabricated using solution processable vanadium oxide (V2O5) hole injection layer to control the carrier transport behavior. The device shows selectable functionalities of photo-detecting and light-emitting behaviors according to the different operating voltage conditions. The device emitted a bright green light at the wavelength of 536 nm, and with the maximum luminance of 31,668 cd/m2 in a forward bias of 8.6 V. Meanwhile, the device could operate as a photodetector in a reverse bias condition. The device was perfectly turned off in a reverse bias, while an increase of photocurrent was observed during the illumination of 520 nm wavelength light on the device. The interfacial electronic structure of the device prepared with different concentration V2O5 solution was measured in detail using x-ray and ultraviolet photoelectron spectroscopy. Both the highest occupied molecular orbital and the gap state levels were moved closer to the Fermi level, according to increase the concentration of V2O5 solution. The change of gap state position enables to fabricate a dual-functional QLEDs. Therefore, the device could operate both as a photodetector and as a light-emitting diode with different applied bias. The result suggests that QLEDs can be used as a photosensor and as a light-emitting diode for the future display industry.

mentioning

confidence: 99%

Dual-functional quantum-dots light emitting diodes based on solution processable vanadium oxide hole injection layer

Park

et al. 2021

Sci Rep

“…Figure 2a shows the temporal response of the photocurrent for the three different TMDC layers with a white light power density of 55 mWcm −2 and a bias voltage of V b = 2 V, with the optical excitation aimed through the transparent backside of the PET substrate (enhancing the light incident on the graphite-TMDC interface). The first devices were found to yield responsivities up to 24 mA W −1 for WS 2 , constituting more than a 10 2 -10 3 improvement compared with other printed LPE photodetectors [36][37][38]44 . A table comparing our devices and those produced from LPE materials can be found in Supplementary Table 1.…”

Section: Resultsmentioning

confidence: 99%

Heterostructures formed through abraded van der Waals materials

et al. 2020

To fully exploit van der Waals materials and their vertically stacked heterostructures, new mass-scalable production routes which are low cost but preserve the high electronic and optical quality of the single crystals are required. Here, we demonstrate an approach to realise a variety of functional heterostructures based on van der Waals nanocrystal films produced through the mechanical abrasion of bulk powders. We find significant performance enhancements in abraded heterostructures compared to those fabricated through inkjet printing of nanocrystal dispersions. To highlight the simplicity, applicability and scalability of the device fabrication, we demonstrate a multitude of different functional heterostructures such as resistors, capacitors and photovoltaics. We also demonstrate the creation of energy harvesting devices, such as large area catalytically active coatings for the hydrogen evolution reaction and enhanced triboelectric nanogenerator performance in multilayer films. The ease of device production makes this a promising technological route for up-scalable films and heterostructures.

“…For future commands, integrated flexible optoelectronics are likely to move toward wireless multifunctionality with sensors, memory, communication, and information charging, which requires many functional components on flexible substrates. [ 129 ] But when exposed to frequent bending or stretching, the strain is inconsistent distribution in whole integrated devices. Cracks may develop in certain functional 2D materials and may slip from substrates due to the mismatching mechanical properties.…”

Section: Discussionmentioning

confidence: 99%

Strain Engineering in 2D Material‐Based Flexible Optoelectronics

Liu

et al. 2020

Small Methods

110

Flexible optoelectronics, as promising components hold shape‐adaptive features and dynamic strain response under strain engineering for various intelligent applications. 2D materials with atomically thin layers are ideal for flexible optoelectronics because of their high flexibility and strain sensitivity. However, how the strain affects the performance of 2D materials‐based flexible optoelectronics is confused due to their hypersensitive features to external strain changes. It is necessary to establish an evaluation system to comprehend the influence of the external strain on the intrinsic properties of 2D materials and the photoresponse performance of their flexible optoelectronics. Here, a focused review of strain engineering in 2D materials‐based flexible optoelectronics is provided. The first attention is on the mechanical properties and the strain‐engineered electronic properties of 2D semiconductors. An evaluation system with relatively comprehensive parameters in functionality and service capability is summarized to develop 2D materials‐based flexible optoelectronics in practical application. Based on the parameters, some strategies to improve the functionality and service capability are proposed. Finally, combining with strain engineering in future intelligence devices, the challenges and future perspective developing 2D materials‐based flexible optoelectronics are expounded.