Transparent and Conductive Inorganic/Polymer‐Composite Encapsulants for Long‐Term Perovskite Solar Cells Operation

An innovative inorganic/polymer-composite encapsulation scheme comprising a polymer-based transparent conductive composite (TCC) coupled with a transparent conductive oxide is introduced to extend the lifetime of moisture-sensitive devices such as perovskite solar cells (PSC). The TCC comprises conductive silver-coated polymethyl methacrylate (Ag-PMMA) microsphere fillers protruding from a transparent non-conductive polymer matrix. TCC samples (5% Ag-PMMA by area) demonstrate high optical transparencies (%T approx. 85% in the 370–1200 nm region), low out-of-plane electrical resistivities (R < 0.2 Ω cm²), and equilibrium permeabilities of less than 1 g mm/m²/day, all of which are well-maintained after 1,000 hours of environmental exposure. In practice, the TCC is employed between two indium zinc oxide (IZO) thin films, with the in-plane conductivity of IZO and the out-of-plane conductivity of TCC working collectively to function as a single encapsulating electrode. This encapsulation scheme is exemplified by benchmarking performances of PSCs subjected to accelerated aging conditions of quasi-maximum power point tracking under light soaking in air at 50 °C, 40% R.H. to 60% R.H. Notable improvements in operational lifetimes are observed, with a champion encapsulated PSC maintaining over 90% of its initial efficiency of 21.65% for up to 1,430 hours, compare to less than 300 hours for an unencapsulated control.. Authors: Outlaw‐Spruell, Kai [University of Hawaii, Honolulu, HI (United States)] (ORCID:0009000274113318); Xu, Jackson [University of Hawaii, Honolulu, HI (United States)]; You, Shuai [National Renewable Energy Laboratory (NREL), Golden, CO (United States)]; Kempe, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States)]; Zhu, Kai [National Renewable Energy Laboratory (NREL), Golden, CO (United States)]. DOE Contract: AC36-08GO28308; EE0010241. Subjects: durability; encapsulant; perovskite solar cell; transparent conductive barrier; water vapor transmission rate