Unravelling donor–acceptor film morphology formation for environmentally-friendly OPV ink formulations

Abstract

Realising bicontinuous interpenetrating network morphologies – with nanoscale phase separation – for donor–acceptor material systems processed from environmentally-friendlier ink formulations.

Using Solubility Parameters to Model More Environmentally Friendly Solvent Blends for Organic Solar Cell Active Layers

“…The HSP values for N2200 were determined from the solubility measurements. Together with earlier reported HSP values for TQ1 [4], possible solvent blends of non-halogenated solvents were calculated by modelling in the HSPiP program. These solvent blends were used for solubility experiments of TQ1:N2200 blends and from successful solvent blends; thin blend films were prepared by spin-coating.…”

“…Using the HSP values for TQ1 determined by Holmes et al [4], i.e., δD = 17.5, δP = 4.0, δH = 3.8, and R 0 = 4.8, makes it possible to make a similar solubility sphere for this polymer. Putting these two spheres into the same three-dimensional graphical representation in Hansen space, as seen in Figure 5, shows an overlap region of the two spheres, the so-called junction.…”

“…An advance in the field of organic solar cells (OSCs) is of increasing interest, both from a fundamental and an applied point of view, as OSCs offer broad opportunities to produce electricity in a sustainable way as well as showing multiple technical benefits, e.g., solution processability, flexibility, and light-weight [1,2,3,4,5,6]. The commercialization of OSC technology will depend on three key factors: Device efficiency, lifetime, and cost [7].…”

“…HSP is theoretically based on thermodynamics and regular solution theories and relies on how the dispersion forces, polar forces, and hydrogen bonding forces (denoted as δD, δP, and δH, respectively) influence the interactions between solvent and solutes and hence the solubility. This model has successfully been applied to several OSC systems [4,16,17,18,19,20,21].…”

An Ink‐Composition Engineering Approach for Upscaling of Organic Solar Cells with High‐Efficiency Retention Factor

“…Organic solar cells (OSCs) have emerged as a promising candidate for production of clean renewable energy due to their potential attributes of low‐cost manufacture, light weight, and flexibility. [ 1–6 ] Recent advances in active layer material synthesis, [ 6–9 ] interface engineering, [ 10–12 ] active layer and device engineering, [ 13–15 ] and morphology [ 16–18 ] have now pushed the device efficiency in excess of 18% for small‐scale spin‐coated single bulk‐heterojunction OSCs. [ 19 ] Such a high power conversion efficiency (PCE) has primarily become achievable through the development of nonfullerene acceptors (NFAs), [ 20–23 ] thereby not only including a grander portion of the light emission spectrum but also reducing/eliminating the energy losses associated with the energy level differences between donor and acceptor molecules in the active layer [ 6,24 ] and optimization of the active layer morphology/phase separation.…”