Paths, solvent-induced conformational defects inside the deposited layers that cannot be controlled influence their morphological properties that, in turn, have an effect on their electrical characteristics [36]. Other disadvantages of this approach consist of (i) the difficulty to deposit organic layers on versatile substrates and on nano-patterned structured substrates, (ii) the preparation of multilayer 4-Aminosalicylic acid MedChemExpress structures and (iii) the usage of materials with diverse solubilities and substrates with different wettabilities [37]. Matrix-Assisted pulsed Laser Evaporation (MAPLE) can overcome the drawbacks of spin coating (in the lab-scale level) being a laser method that makes it possible for the deposition of organic (multi)layers [38] or hybrid composite layers [39] with tuned properties even on plastic substrates [40]. MAPLE was developed within the late 1990s inside a US Naval Investigation Laboratory to supply a gentler pulsed laser evaporation process for organic compounds (specially polymers) layers so that you can preserve their chemical structure during the deposition [41]. MAPLE is definitely an adaptation of pulsed laser deposition (PLD),Coatings 2021, 11,4 ofa method that makes it possible for a stoichiometric transfer, in particular of your inorganic compounds from a source consisting of a pressed strong target, which can contain single or composite materials [42]. However, some papers have been reported around the deposition by PLD of little organic compounds often used inside the OPV location, for instance zinc Tasisulam Purity phthalocyanine (ZnPc) or pentacene [43,44]. The research highlighted (i) the influence with the laser fluence (from 10 to one hundred mJ/cm2) and repetition price (50 and 200 Hz) on the properties on the obtained ZnPc film [43] and (ii) the key effect on the laser fluence along with the utilised wavelength on the electrical traits from the pentacene films [44]. The ability of this laser strategy to deposit thin films depending on polymers has been also evaluated [457]. Therefore, additiontype polymers for instance poly-tetrafluorethylene (PTFE) [45] and poly-methylmethacrylate (PMMA) [46,47] happen to be deposited by PLD. In these situations, the polymeric films are obtained via a “depolymerization onomer ablation epolymerization” mechanism [47], which limits the application of PLD as a laser deposition approach for polymeric layers. Moreover, some attempts happen to be produced to deposit small molecule compounds or polymers by an additional variant of PLD, Resonant Infrared-PLD (RIR-PLD) [48,49]. In this case, the laser wavelength is tuned to an absorption band characteristic for the material intended to be deposit (pressed target) [48]. Tris(8-hydroxyquinoline) aluminum (Alq3) films have been deposited making use of a six.67-micrometer wavelength laser functioning at a 1.five J/cm2 fluence [48], when poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) layers had been obtained by ablation of your pressed target with an eight.3-micrometer wavelength laser working at a 0.5 J/cm2 fluence [49]. Nevertheless, the infrared investigations revealed that the Alq3 films preserved the vibrational characteristic bands from the raw compound, whilst the chemical structure of MEH-PPV was altered throughout the laser deposition. It must be described that the PLD deposition is usually carried in a vacuum chamber, below higher vacuum. Nonetheless, an experimental set-up with a new configuration that will operate in the open air was recently patented [50]. As much as now, some papers currently reported on the application of the pulsed laser deposition in open air (at lab-scale level) inside the depositi.
