Inner Encapsulating Approach for Moisture‐Stable Perovskite Solar Cells

Abstract

The degradation of the perovskite layer in atmospheric air is a critical bottleneck for the commercialization of perovskite solar cells (PSCs). As the moisture and oxygen in air penetrate the charge transport layer/top metal electrode interface, both adjacent layers and perovskite layers decompose in the PSCs. Herein, moisture‐stable inverted PSCs (I‐PSCs) based on methylammonium lead triiodide (MAPbI3) by introducing amine‐functionalized small molecules as metal adhesive layers (MALs) between the electron transport layer (ETL) and metal electrode (here, Cu) are demonstrated. A strong coordination bond of CuN forms at the Cu/MAL interface, leading to the layer–layer growth mode for the dense formation of Cu electrodes with a strong adhesion to the ETL. Thus, this modified electrode prevents the ingress of moisture into the I‐PSCs, resulting in outstanding moisture stability; the efficiency of I‐PSCs retains 90% of the initial efficiency after 200 days of exposure to atmospheric air (25 °C, relative humidity [RH] ≈20–40%). Under harsher conditions (e.g., 25 °C/RH65%, 25 °C/RH85% and immersion in water) for a considerable time period, the modified I‐PSCs manifest relatively no degradation compared with the pristine I‐PSCs. It is believed that this breakthrough provides a significant impact on improving the stability of I‐PSCs.

Photostable organic solar cells based on non-fullerene acceptors with an aminated bathocuproine electron transport layer

“…S3,† the Ag 3d binding energy shifts toward a lower energy from 368.23 eV to 367.80 eV (for BCP) and 367.61 eV (for BCPN), which can be attributed to the strong binding interaction between Ag and the amine functional group. 55–57 The above two experiments indicate that the enhanced dipole moment at the ETL/Ag interface due to attachment of the amine functional group of the BCP (BCPN) leads to lower binding energy. Therefore, the slightly higher J sc and FF of the OSC built using BCPN can be attributed to better charge-carrier extraction or transport from the BHJ layer to the Ag electrode by lowering the energetic barrier at the interfaces.…”

Counter electrodes for perovskite solar cells: materials, interfaces and device stability

“…Kim and coworkers changed the number of amine groups at the end of the BTA alkyl functional group, and its effect on the device stability was explored. 157 The device with three alkyls (BTA-3) exhibited the best moisture stability, retaining 80% of the initial PCE after an exposure time of 500 h. In the XPS measurement, the iodide ion signal of the device without BTA could be observed at the copper electrode, indicating the iodine migration towards the counter electrode. However, this process has been effectively suppressed in the device with BTA-3.…”

Graphene‐Like Monoelemental 2D Materials for Perovskite Solar Cells

“…Reproduced with permission. [ 89 ] Copyright 2021, Wiley‐VCH. h) Flake size distribution of BP nanosheets and i) the corresponding HRTEM image.…”

“…Recently, Park et al. [ 89 ] developed alkylated rGO (AF‐rGO) nanosheets (Figure 7f), which can be dispersed in chlorobenzene at a high concentration, for PSCs with an n‐i‐p architecture. Due to the high dispersibility of AF‐rGO in nonpolar solvents (Figure 7g), a fully covered AF‐rGO film was successfully deposited on top of the PL using a dynamic spin‐coating method.…”