Display process compatible accurate graphene patterning for OLED applications

Abstract

Graphene film can be used as transparent electrodes in display and optoelectronic applications. However, achieving residue free graphene film pixel arrays with geometrical precision on large area has been a difficult challenge. By utilizing the liquid bridging concept, we realized photolithographic patterning of graphene film with dimensional correctness and absence of surface contaminant. On a glass substrate of 100 × 100 mm2 size, we demonstrate our patterning method to fabricate an addressable two-color OLED module of which graphene film pixel size is 170 × 300 µm2. Our results strongly suggest graphene film as a serviceable component in commercial display products. The flexible and foldable display applications are expected to be main beneficiaries of our method.

33‐2: Flexible OLED Panels with Pixilated Graphene Anode

“…Because of the poor adhesion of graphene to its support, graphene film is very prone to damage or loss [13][14][15][16][17]. To resolve this obstacle and stabilize the patterning process, we treated the passivation layer/graphene interface using a liquid substance [18]. Our approach is based on the theory of liquid bridging, which effectively contributes to improving the adhesion and making graphene film globally flat.…”

Laser Patterning a Graphene Layer on a Ceramic Substrate for Sensor Applications

“…Various graphene patterning techniques have been developed. Because of the fine 2D structure of graphene, the photolithography process has been applied successfully to the graphene Hall device [18], a graphene anode for an organic light-emitting diode (OLED) [19], interdigitated electrodes for planar micro-supercapacitors [20], and graphene field-effect transistors [21]. However, producing structures using photolithography requires masking and risks chemical contamination, which can cause unintentional doping of the graphene.…”

“…Summarizing the literature and issues discussed above, two conclusions can be made. First, a variety of methods and substrates can be used for graphene synthesis and to support the graphene layer: the chemical vapor deposition of graphene on various materials, such as metallic foil (Cu, Ni) [16,17], SiC [23], SiO 2 /Si [18,20,22], or on glass [19]; transferring CVD graphene onto SiO 2 /Si [21,24,25,52,54], PMMA [26], or on Si/SiN [27]; laser-induced chemical vapor deposition [34,35]; graphene ink coating on glass [57,58]; direct laser synthesis [37,38]; spin-coating a GO solution onto glass [41][42][43]45], polymer [48,49], or on sapphire [30]; and reactive inkjet printing of GO on textile surfaces [31]. Second, different types of lasers can be used for graphene patterning, including nano-, pico-, and femtosecond pulsed lasers generating beams with wavelengths from UV to IR.…”

A prototype active-matrix OLED using graphene anode for flexible display application

“…In addition, due to the nature of the physical transfer process, it is practically impossible to achieve a defect-free status at the graphene/substrate interface. The patterning issue was overcome by the use of liquid bridging [11]. Liquid bridging brought forth three beneficial effects: increased adhesion of graphene to its substrate, elimination of the air pore defects at the graphene/substrate interface, and surface planarization of the graphene film.…”