Tripodal triazatruxene derivative as a face-on oriented hole-collecting monolayer for efficient and stable inverted perovskite solar cells by Truong, MA, Funasaki, T, Ueberricke, L, Nojo, W, Murdey, R, Yamada, T, Hu, S, Akatsuka, A, Sekiguchi, N, Hira, S, Xie, L, Nakamura, T, Shioya, N, Kan, D, Tsuji, Y, Iikubo, S, Yoshida, H, Shimakawa, Y, Hasegawa, T, Kanemitsu, Y, Suzuki, T, Wakamiya, A