Spontaneous emission mediated by graphene/hexagonal boron nitride/graphene sandwich structure Hong-Qian Mu, Ying Zhou, Tong-Biao Wang, De-Jian Zhang, Wen-Xing Liu, Tian-Bao Yu and Qing-Hua Liao EPL, 136 3 (2021) 37001 Published online: 01 February 2022 DOI: 10.1209/0295-5075/ac3b98