Low energy emission bands in a small molecular fluorene derivative for organic light-emitting diodesS. L. Lou, H.S. Yu, W. M. Ma, Y. Jiang and Q. ZhangEur. Phys. J. D, 50 1 (2008) 21-26DOI: https://doi.org/10.1140/epjd/e2008-00190-3