Achieving light utilization efficiency of 3.88% and efficiency of 14.04% for semitransparent layer-by-layer organic solar cells by diluting donor layer

초록

Series of opaque and semitransparent layer-by-layer organic solar cells (LbL-OSCs) were fabricated by sequential spin-coating PM6:BO-4Cl/L8-BO layers. Narrow bandgap acceptor material BO-4Cl was deliberately selected to incorporate with PM6 for improving exciton dissociation efficiency in donor layer, especially for the photogenerated exciton near ITO electrode. Over 5 % power conversion efficiency (PCE) improvement of opaque LbLOSCs can be obtained by incorporating 10 wt% BO-4Cl in donor layer. It should be highlighted that the average visible transmittance (AVT) of semitransparent LbL-OSCs with 1 nm Au/10 nm Ag as top electrode can be enhanced due to the relatively decreased PM6 content in donor layer along with the increase of BO-4Cl incorporation. The PCE and AVT of semitransparent LbL-OSCs can be simultaneously increased from 12.43 % to 14.04 % and from 21.98 % to 27.69 % by incorporating 30 wt% BO-4Cl in donor layer. The well optimized semitransparent LbL-OSCs with 1 nm Au/10 nm Ag top electrode achieve the light utilization efficiency (LUE) of 3.88 %, which should be among the highest values for semitransparent LbL-OSCs.

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