**1. Introduction**

Organic optoelectronic device such as organic photovoltaics (OPVs) and organic light-emitting devices (OLEDs) focused over the past few decades the attention of both academia and industries due to the possibility to fabricate flexible, transparent devices on large area using low-cost solution processes, leading to cost-effective production [1, 2]. At this stage, in the OPV field, a major concern regards the fabrication of flexible structures with high efficiencies for various applications [3]. Although, OPV with efficiency over 18% has been reported in 2021 [4], further improvements are still needed for making them a real alternative to other photovoltaic cell (PV) technologies (PV based on silicon, PV based on perovskites, etc.). The improvements can be linked to: (i) the type of the organic materials used in the fabrications of the

PV structures; (ii) the deposition techniques used to obtain the organic component as films; and (iii) the different approaches used for enhancing the absorption in the PV structure such as antireflection coatings, back-reflectors, or the surfaces patterning (texturing) [5, 6]. In the PV structures, the thickness of the organic active film is limited by the low carrier mobility and the short exciton diffusion length [7]. An increase in the film thickness leads to a lowering in the device efficiency, while a decrease in the film thickness results in a poor absorption. Lately, some studies reported that the nanopatterning of the transparent electrodes increases the optical path length of light inside the active material improving the performances of the devices [6, 8].

Different optical approaches and structures such as microlens, nanostructured electrodes, scattering layers were used in the field of OLEDs to improve the light extraction efficiency of the devices [9, 10]. The light extraction efficiency is one of the most important parameters of OLED, defined as the ratio of the total number of photons emitted by the OLED and the total number of photons generated within the organic emitter [10, 11]. Thus, the majority of the generated photons in the organic layers are confined inside the device due to the total internal reflection, which takes place at the glass/air and organic/layer substrate interfaces owing to the mismatch of the refractive index [12]. In this way, almost 30% of the emitted photons are trapped in the glass substrate (glass mode), while a 50% are trapped at the organic/anode interface (waveguide mode). Therefore, various methods were used to extract more efficiently the light from the OLEDs [9, 13].

Transparent conductive electrodes (TCE) play a key role in the development of optoelectronic devices such as OPVs, OLEDs, touch screens, electrochromic devices, heat mirrors, smart windows, and so on [14–16]. Over time, various materials such as metal oxides, ultrathin metals, metal nanowires, graphene, carbon nanotubes, conductive polymers, etc., were deposited and investigated as TCE [1, 14]. However, indium tin oxide (ITO) remains the most commonly used TCE due to its remarkable properties such as high transparency (90% at 550 nm wavelength), adequate sheet resistance (10–30 Ω/□), work function (4.7 eV), and reduced roughness (<1 nm) [17, 18]. Besides that, aluminum-doped zinc oxide (AZO) is a suitable metal oxide for replacing ITO since this material met the necessary criteria regarding the high transparency and the electrical resistivity [19, 20].

Transparent conductive oxide (TCO) films can be deposited by numerous chemical and physical methods such as sol-gel [21], spray pyrolysis [22], magnetron sputtering [23], chemical vapor deposition (CVD) [24], atomic layer deposition [25], pulsed laser deposition (PLD) [20], etc., each of them having both advantages and limitations. PLD is a versatile technique used in the deposition of high-quality films based on ITO, AZO, indium-doped zinc oxide (IZO), Ga-doped ZnO (GZO), indium gallium zinc oxide (GIZO), ZnO-Y2O3 (YZO), the obtained TCO layers having adequate properties for optoelectronic device area [26–30].

Patterning techniques such as X-ray lithography, electron projection lithography, ion beam projection lithography, multiple e-beam lithography, extreme ultraviolet lithography, or nanoimprint lithography (NIL) are essential in the niche technology that manufactures high-volume and low-cost nanoscale devices [31**–**34]. The development and improvement of NIL technique have extended the nanoscale fabrication from standard semiconductor devices for electronics and optoelectronics to complex ones for optics, plasmonics, microfluidics, or biomimetic area [35–39]. Among NIL technologies, ultraviolet nanoimprint lithography (UV-NIL) is an efficient technique because it allows the manufacture of a wide range of pattern sizes and shapes on different rigid or flexible substrates [34, 40].

*Pulsed Laser Deposition of Transparent Conductive Oxides on UV-NIL Patterned Substrates… DOI: http://dx.doi.org/10.5772/intechopen.105798*

In this chapter, we present some of our contributions regarding the TCO layers deposited by PLD on flat and UV-NIL nanopatterned glass substrates. Therefore, metal oxides films (ITO and AZO) deposited by PLD were studied for emphasizing their potential applications in the field of optoelectronic devices such as OPVs and OLEDs.
