Spin-Coating Process for 10 cm × 10 cm Perovskite Solar Modules Enabled by Self-Assembly of SnO₂ Nanocolloids

Abstract

Recently, scalable perovskite fabrication techniques for large, uniform, and highly crystalline perovskite layers have been developed by controlling the crystal chemistry of perovskite precursors. However, scalable techniques for the electron and hole transport layers (ETL and HTL) have rarely been investigated. A major challenge in a scalable technique is obtaining a uniform, highly crystalline, and ultrathin ETL at a low temperature. Here, large-area SnO 2 ETLs are fabricated by an electrostatic self-assembly method. The ETLs coated onto haze FTO show high uniformity without pin holes, as confirmed by an electroluminescence image of the perovskite solar module (PSM). In addition, the uniform and pinhole-free SnO 2 coating are indirectly verified by observing the unchanged shunt resistance of the PSC with increasing active area, compared to the conventional SnO 2 ETL-based PSC. On the basis of this self-assembly method, PSMs of areas 25 and 100 cm 2 are fabricated with power conversion efficiencies (PCEs) of 15.3 and 14.0% without shunt resistance loss, respectively.

Hysteresis-less and stable perovskite solar cells with a self-assembled monolayer

“…We speculate that the -OH groups attract the positive ions existing near the SnO 2 surface in our PSCs, although most of the positive ions move to the opposite spiro-OMeTAD side along the internal built-in field. The -OH groups were previously identified from the SnO 2 surface 32,33 . To observe the -OH groups, we characterized the SnO 2 surface with X-ray photoelectron spectroscopy (XPS).…”

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

“…Reproduced with permission. [ 159 ] Copyright, 2019, American Chemical Society. c) Compiled J – V curves of some state‐of‐the‐art mini‐modules using SnO 2 ESLs.…”

“…c) Compiled J – V curves of some state‐of‐the‐art mini‐modules using SnO 2 ESLs. [ 157,159,183,189 ] (Note: Detailed explanations for given areas can be found in Table 4.) d) Summary of the state‐of‐the‐art PCE values of monolithic PSCs with SnO 2 ESLs fabricated on rigid and flexible substrates.…”

“…[ 50 ] Subsequently, Han et al. scaled this technique to mini‐modules, [ 159 ] by using cationic poly(allylamine hydrochloride) (PAH) polyelectrolyte on negatively charged FTO substrates to deposit SnO 2 uniformly over a large area (Figure 4b). In the next step, the pH of the SnO 2 dispersion was adjusted to 11 (more alkaline) to negatively charge the SnO 2 NCs.…”

Design of Perovskite Thermally Co‐Evaporated Highly Efficient Mini‐Modules with High Geometrical Fill Factors

“…To meet the requirements of high quality and large area uniformity for perovskite films, several deposition methods based on solution, vacuum, and solution‐vacuum hybrid processes have been developed and optimized. [ 6–9 ] The recent works based on solution processes, such as by spin‐coating, [ 6,10–19 ] spray‐coating, [ 7 ] blade coating, [ 8,20–23 ] slot‐die coating, [ 24,25 ] softcover, [ 26,27 ] and screen printing [ 28 ] the devices have reached PCEs ranging from 10% to 18% over areas reaching 100 cm 2 . Some strategies such as solvent optimization, [ 23 ] additive engineering, [ 20 ] and substrate temperature control [ 29 ] have been adopted to obtain large crystal size and pinhole‐free film over a large area and thus significantly improve the PCE in the solution‐based processes.…”