Solution-Processed Organic Photovoltaic Cells Fabricated Via the Precursor Approach Using α-Diketone Derivatives of Acenes

Acenes and their derivatives are commonly employed in organic electronics studies. However, they often lack the required solubility for solution deposition, which considerably limits their applicability to cost-effective devices. One of the proposed methodologies to evade this obstacle is the precursor approach, in which a soluble precursor is first deposited by a solution process then converted to a target acene compound within resulting thin films.

The focus of this study is to develop solution-processed thin-film organic photovoltaic (OPV) cells by employing α-diketone derivatives of acenes in active-layer deposition by the precursor approach.¹ α-Diketone-type precursors are characterized by clean, quantitative conversion to corresponding acene compounds by visible-light irradiation even in the solid state. For example, anthradithiophene (ADT) can be obtained from its α-diketone-type precursor (ADTDK) in thin films, allowing solution-process fabrication of planar-junction OPV cells based on ADT as a p-type semiconductor. The maximum photo-conversion efficiency (PCE) of 1.54% was obtained when PC₇₁BM was used as an n-type semiconductor.² In another case, dithienylanthracene (DTAnt) was generated in thin films from its precursor DTAntDK, and the combination with PC₇₁BM led to 1.66% PCE in a p–i–n type OPV cell. Results with more p-extended systems will also be presented.

1. Suzuki, M.; Aotake, T; Yamaguchi Y.; Noguchi, N.; Nakano, H.; Nakayama, K.; Yamada, H. J. Photochem. Photobiol. C. 2014, 18, 50–70.
2. Yamada, H.; Yamaguchi, Y.; Katoh, R.; Motoyama, Y.; Aotake, T.; Kuzuhara, D.; Suzuki, M.; Okujima, T.; Uno, H.; Aratani, N.; Nakayama, K. Chem. Commun. 2013, DOI: 10.1039/C3CC46178E.