Double ETL in ITO-free poly-3-hexylthiophene-based organic solar cells. - J. F. Solís-Vivanco; Rasu Chettiar Aruna Devi; M. C. Arenas-Arrocena; A. Sosa-Domínzuez; Francisco Javier De Moure-Flores; Jose Santos-Cruz (CCE, 2021)