Enhanced efficiency of the Sb2Se3 thin-film solar cell by the anode passivation using an organic small molecular of TCTA

Abstract

Antimony selenide (Sb2Se3) is an emerging solar cell material. Here, we demonstrate that an organic small molecule of 4, 4', 4''-tris(carbazol-9-yl)-triphenylamine (TCTA) can efficiently passivate the anode interface of the Sb2Se3 solar cell. We fabricated the device by the vacuum thermal evaporation, and took ITO/TCTA (3.0 nm)/Sb2Se3 (50 nm)/C60 (5.0 nm)/Alq3 (3.0 nm)/Al as the device architecture, where Alq3 is the tris(8-hydroxyquinolinato) aluminum. By introducing a TCTA layer, the open-circuit voltage is raised from 0.36 to 0.42 V, and the power conversion efficiency is significantly improved from 3.2% to 4.3%. The TCTA layer not only inhibits the chemical reaction between the ITO and Sb2Se3 during the annealing process but it also blocks the electron diffusion from Sb2Se3 to ITO anode. The enhanced performance is mainly attributed to the suppression of the charge recombination at the anode interface.