The central aim of the proposal is to assemble and characterize 2D materials with photochromic bending molecules for the realization of multifunctional atomically thin optoelectronic devices.Bulk semiconductors currently used in electronic devices have intrinsic drawbacks: are rigid, heavy in weight, limited size shrink and require the use of high cost technology to be processed. Thus, research efforts have recently shifted to two-dimensional (2D) atomically thin crystals such as Graphene, transition-metal dichalcogenides (TMDs) and other 2D systems. These materials have the advantage to be low cost, reproducible in large area, and still preserving their high crystalline quality. The high material quality and flexibility make these 2D atomically thin crystals especially attractive for optoelectronic devices and hold the promise for the realization of new generation of storage devices, solar cells, photodiodes, and light-emitting diodes. The strategy in this proposal is to use the strong properties dependency of 2D nanosheets on the holding substrates to engineer new 2D Molecularly Photo-Gated Thin Film Transistors (2D MPG-TFTs) for large area optoelectronic technology. This is achievable through building blocks of 2D exfoliated crystal on top of photochromic self-assembled azobenzene molecules, which modify carrier injection into the 2D nanosheet thus allowing for the observation of gating effect. The molecular photo-gating is achievable through trans to cis isomerization of the molecules and reverse, in close contact with the 2D nanosheet going across a tunable doping mechanism. During the realization of the project, different solutions will be addressed, tailoring the optical doping mechanism, allowing for both the infinite sequential reproducibility and fast answer of the device switching. This will be achieved modifying the different components of the 2D nanosheet-molecular architecture, which are: i) changing the type of photochromic azobenzene molecules as well as the 2D nanosheet material, according to their n- or p-type characters such as to allow the realization of p-n junction; ii) changing the functionalization of the substrate, by controlling the distance between molecules and, therefore, the molecular density and packaging, allowing controlling the charge density injected into the 2D semiconductor and finally, iii) finding molecular solutions for device architectures, made possible on insulating substrates.
News published in Agência FAPESP Newsletter about the scholarship: