Eco-friendly solvent-processed layer-by-layer ternary all-polymer solar cells exhibiting over 18.5% efficiency

초록

In this work, a series of eco-friendly solvent-processed all-polymer solar cells (APSCs) were fabricated by employing the sequentially spin-coating method. Two polymer donor materials PBQx-TCl and PM6 were deliberately selected due to their similar chemical structure, preferring to form the alloyed state for better exciton dissociation and hole transport in the layer-by-layer (LbL) APSCs. The better exciton dissociation between PBQx-TCl and PM6 can be confirmed from PL spectra of neat and blend films, as well as the short-circuit current densities (J(SC)) of special cells without acceptor layer. The optimized ternary LbL APSCs with 30 wt% PM6 in donor layer exhibit the power conversion efficiency (PCE) of 18.55 %, originating from the simultaneously improved J(SC) of 25.16 mA cm(-2), open-circuit voltage (V-OC) of 0.966 V, and fill factor of 76.33 %. The increased V-OC of ternary LbL APSCs is mainly attributed to the decreased energy loss due to the good compatibility of the two polymer donors. The PCE of 18.55 % should be among the highest value for LbL APSCs processed by eco-friendly solvent.

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