First-principles exploration of the interface characteristic between CNT and inorganic lead-free perovskites CsSnX3 (X = Cl, Br, I)

The structural, electronic, and optical characteristics of the CNT/CsSnX3 (X = Cl, Br, I) interfaces are investigated via first-principles calculations. All selected CNT/CsSnX3 interfaces remain stable in energy and their interfacial properties can be varied with the halogen anions changing from Cl to I. The calculated cohesive energy, inter -layer distance as well as electron localization function indicate the CNT/CsSnX3 systems belong to vdW heter-ojunctions with weak interactions. Due to the large potential difference between CNT and CsSnX3, the internal electrostatic field formed at the interface, which reduces the probability of the electron & ndash;hole recombination effectively. The interfacial charges transfer from CsSnX3 to CNT when they contact. The absorption spectra of CNT/CsSnX3 contacts are higher than the corresponding CNT and CsSnX3, which could be attributed to the formation of interfacial contact. What & rsquo;s more, among all selected composites, CNT/CsSnI3 contacts with large charge transfers and minor structural changes should be the most appropriate configurations to get excellent photoelectric properties. These results exhibit interfacial properties of CNT/CsSnX3 from the atomic scale and provide theoretical guidance for developing novel perovskite devices.