Combinatorial Vacuum‐Deposition of Wide Bandgap Perovskite Films and Solar Cells

Abstract

The development of vacuum‐deposited perovskite materials and devices is partially slowed down by the minor research effort in this direction, due to the high cost of the required research tools. But there is also another factor, thermal co‐deposition in high vacuum involves the simultaneous sublimation of several precursors with an overall deposition rate in the range of few Å s−1. This leads to a deposition time of hours with only a single set of process parameters per batch, hence to a long timeframe to optimize even a single perovskite composition. Here we report the combinatorial vacuum deposition of wide bandgap perovskites using 4 sources and a non‐rotating sample holder. By using small pixel substrates, more than 100 solar cells can be produced with different perovskite absorbers in a single deposition run. The materials are characterized by spatially resolved methods, including optical, morphological, and structural techniques. By fine‐tuning of the deposition rates, the gradient can be altered and the best‐performing formulations in standard depositions with rotation can be reproduced. This is viewed as an approach that can serve as a basis to prototype other compositions, overcoming the current limitations of vacuum deposition as a research tool for perovskite films.

Advancing high-throughput combinatorial aging studies of hybrid perovskite thin films via precise automated characterization methods and machine learning assisted analysis

“…Driven by advancements in experimental infrastructure and data processing, 20 automated characterization techniques have greatly improved in recent years, 21 yielding more thorough insights into the respective material properties across libraries. Although first reports have been made to use combinatorial approaches for the optimization of devices, 22 its potential for stability screening with respect to compositional stability has yet to be exploited.…”

Incremental Feeding of Perovskite Powders: Angstrom‐Precision Growth for Single‐Source Solar Cell Fabrication

“…Additionally, the increased complexity of perovskites used in the bestperforming perovskite solar cells makes sublimation challenging, often requiring four or more sources in a conventional co-evaporation setup. [9][10][11][12][13][14][15][16] Besides the composition, the limited thermal stability of the organic ammonium salts implies that it is difficult to maintain them at high temperatures for prolonged periods of time as they will degrade. [17,18] An alternative physical method for the deposition of compound semiconductors is single-source vapor deposition (SSVD).…”

Pure Iodide Multication Wide Bandgap Perovskites by Vacuum Deposition

“…Initially, we tested the simultaneous cosublimation of CsI and PbI 2 (deposition rates r of 0.6 Å/s and 1.2 Å/s, respectively) from two geometrically opposite thermal sources with respect to the sample holder (Figure a), which was kept fixed during the deposition. This allows us to create a compositional gradient and hence facilitate the direct observation of the eventual CsPbI 3 formation . As clearly seen in Figure a, the substrates on the left side (closer to the CsI source) show a darker color, indicating the formation, to some extent, of CsPbI 3 under CsI-rich conditions.…”

“…This allows us to create a compositional gradient and hence facilitate the direct observation of the eventual CsPbI 3 formation. 36 As clearly seen in Figure 1a, the substrates on the left side (closer to the CsI source) show a darker color, indicating the formation, to some extent, of CsPbI 3 under CsIrich conditions. On the right, PbI 2 -rich compositions do not lead to the formation of the perovskite phase, as the films appear yellow, suggesting the formation of the δ-CsPbI 3 phase.…”

“…In the presence of DMAI, a dark CsPbI 3 phase is observed in the lower and central substrates (Figure 1b), extending to the other surrounding substrates. As described in our previous work, 36 the composition of the films in a deposition with substrate rotation resembles closely that of the central substrate when the sample holder is kept fixed. As the color of the central substrate in Figure 1b suggests the formation of the distorted γ-CsPbI 3 perovskite at RT, we prepared a series of films with different amount of DMAI, this time with rotating sample holder.…”