A thermally activated delayed fluorescence material for efficient ternary organic solar cells

In this study, we report the ternary organic solar cells by doping a thermally activated delayed fluorescence (TADF) material (4 s ,6 s )-2,4,5,6-tetra( 9H -carbazol-9-yl) isophthalonitrile (4CzIPN) in the binary poly(3-hexylthiophene) (P3HT) :[6,6]-phenyl-C71-butyric acid methyl ester (PC₇₁BM) blends. Given the complementary absorption with P3HT, 4CzIPN was doped into (P3HT:PC₇₁BM)-based binary blends, and ternary OSCs were developed, The ternary OSCs with 1.0 wt% of 4CzIPN displayed better phase separation of active layer, thus leading to an impressive efficiency of 3.94 % with open-circuit voltage of 0.54 V, short-circuit density of 11.58 mA/cm^-2 and fill factor of 63.32%.