Moisture-tolerant and high-quality α-CsPbI₃ films for efficient and stable perovskite solar modules

Abstract

Crown ether effectively stabilizes the cubic phase of CsPbI3 to inhibit the moisture invasion and phase transformation of CsPbI3 films, producing large-area devices and improving device performance.

Crown Ether‐Assisted Growth and Scaling Up of FACsPbI3 Films for Efficient and Stable Perovskite Solar Modules

“…The 1 H NMR spectra of CH 2 group for Crown in solutions show distinguishable chemical shifts when respectively mixing with CsI, PbI 2, and CsI+PbI 2 , demonstrating a stronger interaction with Cs + ion than that with Pb 2+ ion due to the higher nucleophilicity of oxygen in Crown with Cs + ions. [ 31 ] In this regard, pure FAPbI 3 films were produced without introducing Cs + cations (detailed experiment as in Supporting Information), in which almost indistinguishable crystallinity and PbI 2 species were observed no matter with or without Crown (Figure S6a, Supporting Information). And the corresponding PSCs also displayed the similar low efficiencies (Figure S6b, Supporting Information) and Table S1, Supporting Information, which demonstrated the little influence of Crown on the synthesis of FAPbI 3 films in spite of the interaction between Pb 2+ cations and Crown.…”

“…Understandably, as Crown could not doped into the crystal lattice, after crystallization, the molecules would self‐assembled on the surface and grain boundaries through the strong interactions with metal ions (Figure S10, Supporting Information). [ 31 ] X‐ray photoelectron spectroscopy (XPS) measurements were further performed to investigate the detailed chemical states in the Crown‐manipulated perovskite films (Figure 2c,d). The XPS doublet peaks of Cs 3d 3/2 and Cs 3d 5/2 were detected at the energy of 738.4 and 724.5 eV in the FACsPbI 3 film.…”

“…With this motivation, a novel crown‐ether‐tailoring strategy was developed in this work to enable the scalable fabrication of stable and high‐quality FACs‐based perovskite films. Besides the previously reported effect of the crown ether in avoiding the phase transition by stabilizing the inorganic perovskite materials or improving precursor stability, [ 30–32 ] another novel function is demonstrated that the in situ tailoring of crown ether can effectively manipulate the growth process toward high‐quality FACsPbI 3 films, which makes it applicable to the fabrication of large‐area and stable perovskite films. By employing the as‐produced films, the champion efficiency of 20.48% with excellent storage stability over 1000 h in the fabricated PSCs was readily achieved.…”

Indoor application of emerging photovoltaics—progress, challenges and perspectives

“…Similarly, Chen et al proposed a surface passivation method of drop-casting an 18-crown-6 ether (Crown) lm on the CsPbI 3 lm surface. 100 As shown in Fig. 11d, pristine a-phase CsPbI 3 has high sensitivity to humidity, transferring to the a-dor d-phases with H 2 O molecules attacking the surface.…”

“…To obtain a stable perovskite phase, the adoption of mixed cation perovskites or inorganic perovskites has been established as a promising strategy under 1 sun condition, 49,50 which may be also effective in the stability enhancement of indoor PPVs. 100,101 Singh et al reported that the Cs-tuned Cs x (FA 0.83 MA 0.17 ) (1Àx) Pb(I 0.83 Br 0.17 ) 3 (where x is the mole fraction of Cs) perovskite devices can achieve an optimal PCE of $17% under AM1.5G condition when x ¼ 0.05 and should also obtain decent device performance under low light conditions considering its extraordinary stability in the ambient atmosphere. 101 This mixed-halide PPV device showed no signicant degradation in device performance upon exposure to ambient air under dark conditions with RH 20-35% (see Fig.…”