2 research outputs found
High-Performance Phototransistors Based on PDIF-CN2 Solution-Processed Single Fiber and Multifiber Assembly
Here we describe the fabrication of organic phototransistors based on either single or multifibers integrated in three-terminal devices. These self-assembled fibers have been produced by solvent-induced precipitation of an air stable and solution-processable perylene di-imide derivative, i.e., PDIF-CN2. The optoelectronic properties of these devices were compared to devices incorporating more disordered spin-coated PDIF-CN2 thin-films. The single-fiber devices revealed significantly higher field-effect mobilities, compared to multifiber and thin-films, exceeding 2 cm2 Vâ1 sâ1. Such an efficient charge transport is the result of strong intermolecular coupling between closely packed PDIF-CN2 molecules and of a low density of structural defects. The improved crystallinity allows efficient collection of photogenerated Frenkel excitons, which results in the highest reported responsivity (R) for single-fiber PDI-based phototransistors, and photosensitivity (P) exceeding 2 Ă 103 AWâ1, and 5 Ă 103, respectively. These findings provide unambiguous evidence for the key role played by the high degree of order at the supramolecular level to leverage the materialâs properties toward the fabrication of light-sensitive organic field-effect transistors combining a good operational stability, high responsivity and photosensitivity. Our results show also that the air-stability performances are superior in devices where highly crystalline supramolecularly engineered architectures serve as the active layer
Phototuning Selectively Hole and Electron Transport in Optically Switchable Ambipolar Transistors
One of the grand challenges in organic electronics is to develop multicomponent materials wherein each component imparts a different and independently addressable property to the hybrid system. In this way, the combination of the pristine properties of each component is not only preserved but also combined with unprecedented properties emerging from the mutual interaction between the components. Here for the first time, that triâcomponent materials comprised of an ambipolar diketopyrrolopyrroleâbased semiconducting polymer combined with two different photochromic diarylethene molecules possessing ad hoc energy levels can be used to develop organic fieldâeffect transistors, in which the transport of both, holes and electrons, can be photoâmodulated. A fully reversible lightâswitching process is demonstrated, with a lightâcontrolled 100âfold modulation of pâtype charge transport and a tenfold modulation of nâtype charge transport. These findings pave the way for photoâtunable inverters and ultimately for completely reâaddressable highâperformance circuits comprising optical storage units and ambipolar fieldâeffect transistors