Enhancing performance of two‐step fabricated perovskite solar cells with sulfonium triflate‐based additive
Yeeun Kim, Hyunjun Lee, Cheong Beom Lee, Beomjin Kim, Nayoon Kwon, Taewoong Son, Jaehee Lee, Jaegwan Sin, Tae Joo Shin, JungYup Yang, Kyeounghak Kim, Jangwon Seo
Abstract
Abstract We incorporated triphenylsulfonium triflate (TPST), a sulfonium‐based additive consisting of polar triflate and bulky hydrophobic phenyl rings, to the PbI 2 precursor solution for preparation of less‐defect perovskite film via two‐step fabrication. TPST induced localized alterations in the array of the PbI 2 structure due to its large size, thereby forming a more discontinuous and coarser surface with a greater number of pinholes and subsequently facilitating more efficient organic–inorganic reactions. As a result, we achieved the production of thick perovskite films with enlarged granules and decreased PbI 2 residuals in the two‐step fabrication process. Furthermore, TPST facilitated the passivation of bulk film defects by increasing the binding energy with the defects. Consequently, the ITO/SnO 2 np‐based device and the FTO/CBD SnO 2 ‐based device obtained the best PCEs of 23.88% and 24.30%, respectively. Furthermore, the moisture stability of the perovskite was improved by the hydrophobic character of the TPST additive. image