Split-second nanostructure control of a polymer:fullerene photoactive layer using intensely pulsed white light for highly efficient production of polymer solar cells

Instantaneous Pulsed-Light Cross-Linking of a Polymer Gate Dielectric for Flexible Organic Thin-Film Transistors

We report the instantaneous pulsed-light cross-linking of polymer gate dielectrics on a flexible substrate by using intensely pulsed white light (IPWL) irradiation. Irradiation with IPWL for only 1.8 s of a poly(4-vinylphenol) (PVP) thin film with the cross-linking agent poly(melamine-co-formaldehyde) (PMF) deposited on a plastic substrate was found to yield fully cross-linked PVP films. It was confirmed that the IPWL-cross-linked PVP films have smooth pinhole-free surfaces and exhibit a low leakage current density, organic solvent resistance, and good compatibility with organic semiconductor, and that they can be used as replacements for typical PVP dielectrics that are cross-linked with time and energy intensive thermal heating processes. The synchronization of the IPWL irradiation with substrate transfer was found to enable the preparation of cross-linked PVP films on large area substrates with a highly uniform capacitance. Flexible OTFT based on IPWL-cross-linked PVP dielectrics were found to exhibit good electrical performance that is comparable to that of devices with thermally cross-linked PVP dielectric, as well as excellent deformation stability even at a bending radius of 3 mm.

Photonic welding of ultra-long copper nanowire network for flexible transparent electrodes using white flash light sintering

A schematic representation of the white flash light welding process of a percolated Cu NW network electrode.

Intense pulsed light induced crystallization of a liquid-crystalline polymer semiconductor for efficient production of flexible thin-film transistors

The split-second crystallization of a conjugated polymer by irradiation of intense pulsed white light improved the performance of flexible thin-film transistors.

Improved optical sintering efficiency at the contacts of silver nanowires encapsulated by a graphene layer

Graphene/silver nanowire (AgNWs) stacked electrodes, i.e., graphene/AgNWs, are fabricated on a glass substrate by air-spray coating of AgNWs followed by subsequent encapsulation via a wet transfer of single-layer graphene (SLG) and multilayer graphene (MLG, reference specimen) sheets. Here, graphene is introduced to improve the optical sintering efficiency of a xenon flash lamp by controlling optical transparency and light absorbing yield in stacked graphene/AgNW electrodes, facilitating the fusion at contacts of AgNWs. Intense pulsed light (IPL) sintering induced ultrafast (<20 ms) welding of AgNW junctions encapsulated by graphene, resulting in approximately a four-fold reduction in the sheet resistance of IPL-treated graphene/AgNWs compared to that of IPL-treated AgNWs. The role of graphene in IPL-treated graphene/AgNWs is further investigated as a passivation layer against thermal oxidation and sulfurization. This work demonstrates that optical sintering is an efficient way to provide fast welding of Ag wire-to-wire junctions in stacked electrodes of graphene/AgNWs, leading to enhanced conductivity as well as superior long-term stability under oxygen and sulfur atmospheres.