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Resonant-infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a promising deposition technology for the fabrication of conjugated polymer-based optoelectronic devices for two primary reasons: (i) the ability to control film morphology, and (ii) the ability to deposit multi-layered heterostructures. This article reviews a variation of RIR-MAPLE that uses emulsified targets of organic solvents and water such that the incident laser wavelength (Er:YAG at 2.9 μm) is resonant with hydroxyl (O–H) bonds in the host matrix, which are absent from the guest material. The novelty of the approach lies in the fact that while most polymers of interest and many compatible solvents do not resonantly absorb the laser energy at 2.9 μm, the emulsion with water enables high-quality, thin-film deposition with minimal photochemical and structural degradation for almost any polymer of interest. In addition, the advantages of emulsion-based RIR-MAPLE for conjugated polymer-based optoelectronic devices are demonstrated by two important studies. First, conjugated polymer films deposited by RIR-MAPLE are shown to have higher hole drift mobilities than films deposited using traditional drop-casting and spin-casting techniques. Second, the unique capability of RIR-MAPLE to enable conjugated polymer-based optical heterostructures is demonstrated by the fabrication and characterization of a multi-layer, polymer distributed Bragg reflector.

CdSe colloidal quantum dot / poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-(1-cyano vinylene)phenylene] hybrid nanocomposite thin films were deposited using resonant infrared matrix-assisted pulsed laser evaporation. The distributions of CdSe colloidal quantum dots within the polymer matrices of as-grown films were evaluated using transmission electron microscopy, and the optical properties of these films were determined by photoluminescence spectroscopy. These measurements demonstrate that: i) depending upon the deposition parameters used, the CdSe colloidal quantum dot distribution can be tuned between two morphology extremes, i.e. clustering or homogenous dispersion; and ii) the constituent materials of the nanocomposite are not damaged in any way that affects structural or optical properties by the deposition process. The demonstrated ability to control nanoparticle distribution within organic films has not been achieved by other deposition techniques and could enhance the performance of optoelectronic devices based on these materials.

Poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-(1-cyanovinylene)-phenylene] (MEH-CN-PPV) thin films were deposited using resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) from targets comprising differing ratios of phenol to ice to assess the impact of laser-target absorption depth on film morphology. The surface and internal morphologies of as-deposited and annealed films indicate that the RIR-MAPLE process can be tuned to favor ablation with more or less vaporous ejecta by tuning the laser-target absorption depth. The demonstrated ability to tune between more or less vaporous ejecta strongly impacts the subsequent morphologies of the deposited films, and has important implications to realizing optoelectronic devices using the RIR-MAPLE process.

Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a variation of pulsed laser deposition that is useful for organic-based thin films because it reduces material degradation by selective absorption of infrared radiation in the host matrix. A unique emulsion-based RIR-MAPLE approach has been developed that reduces substrate exposure to solvents and provides controlled and repeatable organic thin film deposition. In order to establish emulsion-based RIR-MAPLE as a preferred deposition technique for conjugated polymer or hybrid nanocomposite optoelectronic devices, studies have been conducted to demonstrate the value added by the approach in comparison to traditional solution-based deposition techniques, and this work will be reviewed. The control of hybrid nanocomposite thin film deposition, and the photoconductivity in such materials deposited using emulsion-based RIR-MAPLE, will also be reviewed. The overall result of these studies is the demonstration of emulsion-based RIR-MAPLE as a viable option for the fabrication of conjugated polymer and hybrid nanocomposite optoelectronic devices that could yield improved device performance.

We report direct measurement of spectrally selective absorption properties of PbSe and PbS colloidal quantum dots (CQDs) in Si nanomembrane photonic crystal cavities on flexible polyethylene terephthalate (PET) substrates. Enhanced optical absorption was obtained when CQD absorption overlaps with photonic crystal Fano resonances. On the other hand, no absorption was observed when the Fano resonance has no spectral overlap with the CQD absorption bands. The measurement results agree well with the simulation results obtained based on 3D FDTD and RCWA simulation techniques. Measured angular and polarization properties also agree well with Fano resonance transmission properties, which were obtained experimentally and, theoretically based on simulated dispersion properties and transmission properties. Bending induced spectral shifts were characterized for potentially flexible photonic device applications.

We report here modified absorption property of colloidal quantum dots (CQDs) inside flexible Fano filters—made of patterned single crystalline silicon nanomembrane transferred onto flexible plastic substrates. Enhanced optical absorption was obtained both experimentally and theoretically, when the CQD absorption peak spectrally overlaps with Fano resonance peak. On the other hand, suppressed absorption was observed when the Fano resonance has no spectral overlap with the CQD absorption bands.

A unique and distinct approach to unipolar, intraband transitions appropriate for room-temperature, mid- and long-wave-infrared (IR) photodetection is to use active regions comprising colloidal quantum dots (CQDs) synthesized by inorganic chemistry embedded in conjugated polymers. The polymer not only enhances quantum confinement of and electron localization in CQDs, but it also assists in the conduction of electrons photogenerated by the absorption of IR light. Preliminary demonstrations of intraband, mid-wave IR absorption and Fourier transform IR (FTIR) spectral response at room temperature in CdSe/MEH-CN-PPV hybrid nanocomposite thin films are promising, yet the inherent lack of control over hybrid nanocomposite morphology due to solution-based deposition is an inherent challenge. Matrix-assisted pulsed laser evaporation is a vacuum-based deposition technique that could address this challenge by providing more homogeneous distributions of CQDs in hybrid nanocomposite thin films.