| 초록 |
When lead-based colloidal quantum dots (CQD)s are exposed to ambient air, the oxidized surface leads to unfavorable band alignments between the active and hole transfer layers. To prevent degradation of PV performance, we need a reasonable surface reconstruction strategy. Thus, we performed DFT calculations to unveil the role of GuSCN on the PbS surface reconstruction and formation of an epitaxial perovskite bridge. We compared adsorption energies of O, OH- and SCN-. The order of Eads has O* ＜ OH* ＜ SCN* which implies that the surface reconstruction by SCN passivation is thermodynamically favorable. Furthermore, we designed the PbS/GuPbX3-X(SCN)X interface models along the (111) and (100) facets. From the results of formation energies, we confirmed that the interface structures along the (111) facet are suitable. In particular, the two-sided interface is more stable than the one-sided interface, which means that CQDs can be epitaxially connected by the perovskite layer. |
