288
S. Papazoglou and I. Zergioti
9.4 Applications of LIFT
The rapid evolution of the LIFT technique and the development of various alternative approaches for the realization of the transfer has lead to the incorporation
of LIFT into the fabrication of different devices for Organic Thin-Film Transistors (OTFTs), Organic Light-Emitting Diodes (OLEDs), electrical interconnects in
integrated circuits (IC), chemical, and biological sensors applications. Since resolution and reproducibility are among the current market trends, LIFT has shown great
promise in achieving both targets through the minimization of the printed features and
the repeatability of the process. This is further highlighted by the number of publications that have been reported as well as from the establishment of the technique in
industrial processes as it will be described in the next paragraphs.
9.4.1 Laser Printing for Organic Electronics
and Micropower Devices
The market needs in the organic electronics community require a decrease in the
device footprint while at the same time integration complexity and increase in the
number of the active components are also required. Laser printing enables the high
speed, contactless, and high resolution transfer of a wide range of organic materials
of varying viscosities providing certain advantages compared to conventional deposition techniques such as inkjet printing that suffers from inherent limitations namely
nozzle clogging when it comes to high viscosity solutions and the need for masks
and clean room facilities in the case of lithographic processes, where highly toxic
etchants and developer solutions are also used [53]. LIFT has been successfully used
for OTFTs applications [19, 54–60], OLEDs [28, 61–63], solar cells/photovoltaics
[64–66], microbatteries [67–70] and ultra and microcapacitors [51, 71, 72]. More
specifically, OTFTs devices via LIFT have been demonstrated for the simultaneous
multilayer transfer of diPhAc-3T (p-type semiconductor), parylene-C as the dielectric layer and a thin silver layer that served as the gate electrode that resulted in a
functional top gate OTFT [30] (Fig. 9.7).
In another work, OTFTs using pentacene with bottom-contact and top-contact
configurations have been reported using LIFT. The source-drain electrodes were
formed using silver NPs inks—printed with a Nd:YVO 4 laser source (λ = 355 nm,
30 ns)—with reporting field-effect mobilities at the order of 0.11 cm
2 /V s [60]. Airstable high performing OTFTs have been also reported by Rapp et al. [19], with hole
mobilities up to 0.04 cm
2 /V s, threshold voltage V t near 0 V and Ion/Ioff ratio up
to 2.8 × 10
5 . Additionally, tricolor OLEDs have been transferred using LIFT in a
multilayer stack approach that consisted of the aluminum cathode and the blue, red
or green light-emitting polymer (LEP) layer. The device showed good efficiencies
comparable to that of conventional spin-coated devices [73]. BA-LIFT has been
also employed for the fabrication of OLEDs with electroluminescence emission and
S. Papazoglou and I. Zergioti
9.4 Applications of LIFT
The rapid evolution of the LIFT technique and the development of various alternative approaches for the realization of the transfer has lead to the incorporation
of LIFT into the fabrication of different devices for Organic Thin-Film Transistors (OTFTs), Organic Light-Emitting Diodes (OLEDs), electrical interconnects in
integrated circuits (IC), chemical, and biological sensors applications. Since resolution and reproducibility are among the current market trends, LIFT has shown great
promise in achieving both targets through the minimization of the printed features and
the repeatability of the process. This is further highlighted by the number of publications that have been reported as well as from the establishment of the technique in
industrial processes as it will be described in the next paragraphs.
9.4.1 Laser Printing for Organic Electronics
and Micropower Devices
The market needs in the organic electronics community require a decrease in the
device footprint while at the same time integration complexity and increase in the
number of the active components are also required. Laser printing enables the high
speed, contactless, and high resolution transfer of a wide range of organic materials
of varying viscosities providing certain advantages compared to conventional deposition techniques such as inkjet printing that suffers from inherent limitations namely
nozzle clogging when it comes to high viscosity solutions and the need for masks
and clean room facilities in the case of lithographic processes, where highly toxic
etchants and developer solutions are also used [53]. LIFT has been successfully used
for OTFTs applications [19, 54–60], OLEDs [28, 61–63], solar cells/photovoltaics
[64–66], microbatteries [67–70] and ultra and microcapacitors [51, 71, 72]. More
specifically, OTFTs devices via LIFT have been demonstrated for the simultaneous
multilayer transfer of diPhAc-3T (p-type semiconductor), parylene-C as the dielectric layer and a thin silver layer that served as the gate electrode that resulted in a
functional top gate OTFT [30] (Fig. 9.7).
In another work, OTFTs using pentacene with bottom-contact and top-contact
configurations have been reported using LIFT. The source-drain electrodes were
formed using silver NPs inks—printed with a Nd:YVO 4 laser source (λ = 355 nm,
30 ns)—with reporting field-effect mobilities at the order of 0.11 cm
2 /V s [60]. Airstable high performing OTFTs have been also reported by Rapp et al. [19], with hole
mobilities up to 0.04 cm
2 /V s, threshold voltage V t near 0 V and Ion/Ioff ratio up
to 2.8 × 10
5 . Additionally, tricolor OLEDs have been transferred using LIFT in a
multilayer stack approach that consisted of the aluminum cathode and the blue, red
or green light-emitting polymer (LEP) layer. The device showed good efficiencies
comparable to that of conventional spin-coated devices [73]. BA-LIFT has been
also employed for the fabrication of OLEDs with electroluminescence emission and