Analysis of the role of hole transport layer materials to the performance of perovskite solar cellIstighfari Dzikri, Michael Hariadi, Retno Wigajatri Purnamaningsih and Nji Raden PoespawatiE3S Web Conf., 67 (2018) 01021DOI: https://doi.org/10.1051/e3sconf/20186701021