A double-acceptor as a superior organic dye design for p-type DSSCs: high photocurrents and the observed light soaking effect†
Herein, we report three novel single donor double acceptor dyes, BH2, 4, and 6, for use in p-type dye sensitized solar cells (DSSCs). BH4 yields one of the highest photocurrents, 7.4 mA cm−2, to date. The high performance is achieved via a shorter synthetic route and no exotic materials or cell-building techniques. We suggest a structural principle when building dyes whereby one adopts a double acceptor/single anchor when a triphenylamine moiety is incorporated into a dye for p-type DSSCs. This strategy increases the molar extinction coefficient while simultaneously reducing the number of synthetic steps. The molar extinction coefficients (99 980 M−1 cm−1) reported herein are among the highest reported. Finally, we report the first-ever-observed light soaking effect in p-type DSSCs.