Excellent Intrinsic Long‐Term Thermal Stability of Co‐Evaporated MAPbI₃ Solar Cells at 85 °C

Abstract

Thermal stability is a critical criterion for assessing the long-term stability of perovskite solar cells (PSCs). Here, it is shown that un-encapsulated co-evaporated MAPbI 3 (TE_MAPbI 3 ) PSCs demonstrate remarkable thermal stability even in an n-i-p structure that employs Spiro-OMeTAD as hole transport material (HTM). TE_MAPbI 3 PSCs maintain over ≈95% and ≈80% of their initial power conversion efficiency (PCE) after 1000 and 3600 h respectively under continuous thermal aging at 85 °C. TE_MAPbI 3 PSCs demonstrate remarkable structural robustness, absence of pinholes, or significant variation in grain sizes, and intact interfaces with the HTM, upon prolonged thermal aging. Here, the main factors driving TE_MAPbI 3 stability are assessed. It is demonstrated that the excellent TE_MAPbI 3 thermal stability is related to the perovskite growth process leading to a compact and almost strain-stress-free film. On the other hand, un-encapsulated PSCs with the same architecture, but incorporating solutionprocessed MAPbI 3 or Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 as active layers, show a complete PCE degradation after 500 h under the same thermal aging condition. These results highlight that the control of the perovskite growth process can substantially enhance the PSCs thermal stability, besides the chemical composition. The TE_MAPbI 3 impressive long-term thermal stability features the potential for field-operating conditions.

Co‐Evaporated MAPbI3 with Graded Fermi Levels Enables Highly Performing, Scalable, and Flexible p‐i‐n Perovskite Solar Cells

“…[30] Co-evaporated PSCs have also recently demonstrated a remarkable intrinsic long-term stability thanks to the un-straitened perovskite films grown by coevaporation. [31] The excellent scalability of this technique results in co-evaporated perovskite mini-modules achieving PCEs well above 18% paving the way for PSC commercialization. [10,20] Although most of the highly efficient PSCs are based on the n-i-p structure, [32][33][34] the advantages provided by the p-i-n configuration such as a reduction in hysteresis and processing complexity as well as an increase in cost-effectiveness, are rapidly gaining the attention of the scientific community.…”

Vacuum‐Processed Metal Halide Perovskite Light‐Emitting Diodes: Prospects and Challenges

“…Recently it has been demonstrated that thermally co-evaporated perovskites can achieve extraordinary thermal stability in solar cells, thanks to the minimization of the tensile stress within the films. [85] These results are also promising for PeLEDs.…”

Multifunctional Crosslinking‐Enabled Strain‐Regulating Crystallization for Stable, Efficient α‐FAPbI3‐Based Perovskite Solar Cells

“…During the submission of this work, Bruno and co‐workers also found the existence of tensile stress in antisolvent‐treated perovskite film, which is consistent with our results. [ 44 ] The already crosslinked PTMTA case has the same negative slope as the control, indicating little effect on the residual strain. The TMTA post‐treated film on the surface can release the residual tensile strain to a certain extent, according to the slightly lower slope of linear fitted 2θ–sin 2 ψ.…”