Exploring the properties of carbazole-based derivatives as hole transport materials from first principle and MD simulation

Abstract

Abstract Although the perovskite solar cell (PSC) without hole transport materials (HTM) has been developed, the power conversion efficiency (PCE) is still less than 15%. Exploring efficient and low cost HTMs is still the urgent requirement for the further development of efficient PSCs. Three new HTMs, H5, H6, and H7, are designed on the basis of X25, in which N-p-methoxyphenyl-1-naphthylamine, 9,9-dimethyl-acridine, and 9,9-dimethyl-10-phenyl-9,10-dihydroacridine are utilized as side groups, respectively, along with the 9-(4-methoxyphenyl)-9H-carbazole core. The performance of new designed molecules is evaluated from various aspects including frontier molecular orbital, absorption spectrum, and hole mobility. More importantly, the interfacial properties between HTM and CH3NH3PbI3 (110) surface are explored. After adsorption, the band gap of CH3NH3PbI3 (110) surface is almost kept but the energy levels of HTMs are varied indicating that it is necessary to study the adsorption properties rather than only the isolated HTM molecule. Actually, the side groups in H5, H6, and H7 have been employed as side groups to constitute molecules applied in some relevant regions, which would provide an alternative pathway to develop new HTM rather than synthesis of new groups.