Efficient free triplet generation follows singlet fission in diketopyrrolopyrrole polymorphs with goldilocks coupling

Andrew M. Levine, Guiying He, Guanhong Bu, Pablo Ramos, Fanglue Wu, Aisha Soliman, Jacqueline Serrano, Dorian Pietraru, Christopher Chan, James D. Batteas, Marta Kowalczyk, Seogjoo J. Jang, Brent L. Nannenga, Matthew Y. Sfeir, Esther H.R. Tsai, Adam B. Braunschweig