Emulsion-Based RIR-MAPLE Deposition of Conjugated Polymers: Primary Solvent Effect and Its Implications on Organic Solar Cell Performance

Abstract

Emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been demonstrated as an alternative technique to deposit conjugated polymer films for photovoltaic applications; yet, a fundamental understanding of how the emulsion target characteristics translate into film properties and solar cell performance is unclear. Such understanding is crucial to enable the rational improvement of organic solar cell (OSC) efficiency and to realize the expected advantages of emulsionbased RIR-MAPLE for OSC fabrication. In this paper, the effect of the primary solvent used in the emulsion target is studied, both experimentally and theoretically, and it is found to determine the conjugated polymer cluster size in the emulsion as well as surface roughness and internal morphology of resulting polymer films. By using a primary solvent with low solubility-in-water and low vapor pressure, the surface roughness of deposited P3HT and PCPDTBT polymer films was reduced to 10 nm, and the efficiency of P3HT:PC 61 BM OSCs was increased to 3.2% (∼100 times higher compared to the first MAPLE OSC demonstration [Caricato, A. P.; et al. Appl. Phys. Lett. 2012, 100, 073306]). This work unveils the mechanism of polymer film formation using emulsion-based RIR-MAPLE and provides insight and direction to determine the best ways to take advantage of the emulsion target approach to control film properties for different applications.

Molecular weight dependent structure and charge transport in MAPLE‐deposited poly(3‐hexylthiophene) thin films

“…Specifically, the sacrificial host solvent is chosen such that it absorbs the majority of the laser energy, thereby altogether avoiding the photochemical degradation of the guest polymer. Prior studies have demonstrated that the chemical structure, molecular weight, and molecular weight distribution are maintained through judicious choice of the MAPLE deposition parameters …”

Molecular organization in MAPLE-deposited conjugated polymer thin films and the implications for carrier transport characteristics

“…With its unprecedented capabilities, MAPLE has readily been exploited for growing thin polymer films for a wide range of applications including sensors, drug delivery and medical implants . Recently, promising findings have also been reported on the properties of MAPLE deposited conjugated polymer films for solar cells, organic light emitting diodes, and other organic electronic applications . Although operational devices have been made, the detailed molecular structure and the fundamental connection between processing, morphology, and transport in those devices are still poorly understood.…”

Janus or homogeneous nanoparticle mediated self-assembly of polymer electrolyte fuel cell membranes

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