Wannier-Koopmans method calculations of organic molecule crystal band gaps Shucheng Li, Mouyi Weng, Jianshu Jie, Jiaxin Zheng, Feng Pan and Lin-Wang Wang EPL, 123 3 (2018) 37002 Published online: 04 September 2018 DOI: 10.1209/0295-5075/123/37002