As a thermally activated delayed fluorescence (TADF) emitter [4,5-di (9H-carbazol-9-yl) phthalonitrile (2CzPN)], it can enhanced performance of small molecule organic solar cells. The absorption spectrum of 2CzPN is complementary with the donor SubPc, and its photoluminescence spectrum overlaps with the absorption spectrum of the active layer. The estimated hole injection barrier slightly increases from 0.809eV (without 2CzPN) to 0.874eV (with 5nm 2CzPN) and the hole mobility simultaneously decreases. [1,2]
[1] SUN J W, KIM K H, MOON C, et al. Highly Efficient Sky-Blue Fluorescent Organic Light Emitting Diode Based on Mixed Cohost System for Thermally Activated Delayed Fluorescence Emitter (2CzPN).[J]. ACS applied materials & interfaces, 2016, 8 15: 9806-9810. DOI:10.1021/acsami.6b00286.
[2] ZHENG Y, YU J, LI W, et al. Performance enhancement of small molecular solar cells via luminescent sensitizer 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN)[J]. Journal of Physics D: Applied Physics, 2020, 53. DOI:10.1088/1361-6463/ab4c07.
