Y7

Synonym: 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2",3":4′,5′]-thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile

BTP-4Cl is a high performance, low bandgap, non-fullerene accpetor (NFA). It is the chlorinated derivative of the fused benzothiadiazole-based NFA, Y6. It offer high power conversion efficiency (PCE) when pairing with p-type polymer PM6. A 9 mm² single junction device of this blend provided a PCE of 16.5% at thickness of ~ 100nm, and provided a PCE of >13% at a thickness of ~300 nm (for the active layer). An impressive PCE of >15% was reached for this blend with a 1 cm² active layer. In general, Y7 showed improved performances over Y6, mainly due to its highest photoluminescence, lower non-radiative energy loss, and a higher Voc of 0.867 V vs 0.834 V for Y6.

Y7 is a highly conjugated organic semiconductor, electron deficient due to its structure and hence suitable for use as a n-type non-fullerene electron acceptor(NFA) in OPV devices. It has an absorption range that extends to the near infrared (NIR) and has demonstrated a power conversion efficiency (PCE) up to15.7% with PBDB-T-2F (PM6) as the polymer donor.