Efficient control
of crystallization and defects of perovskite
films are the key factors toward the performance and stability of
perovskite solar cells (PSCs), especially for the preparation of large-area
PSCs devices. Herein, we directly embedded surfactant-like monoammonium
zinc porphyrin (ZnP) compound into the methylammonium (MA+) lead iodide perovskite film to blade-coat large-area uniform perovskite
films as large as 16 cm2. Efficiency as high as 18.3% for
blade-coating large-area (1.96 cm2) PSCs with ZnP was unprecedentedly
achieved, while the best efficiency of fabricated small-area (0.1
cm2) device was up to 20.5%. The detailed analyses demonstrated
the functions of ZnP in crystallization control and defects passivation
of perovskite surfaces and grain boundaries. As a consequence, the
ZnP-encapsulated devices retained over 90% of its initial efficiency
after 1000 h with a humidity of about 45% at 85 °C. This research
presents a facile way to achieve the synergistic effect of large-area
coating, morphology tailoring, and defect suppression based on the
molecular encapsulation strategy for perovskite films, further improving
the photovoltaic performance and stability of PSCs.
Defects within the grain boundaries (GBs) of halide perovskite films make fabrication of efficient and stable perovskite solar cells (PSCs) highly challenging. Here, a low-cost tetra-ammonium zinc phthalocyanine (ZnPc) was used to post-treat the MAPbI (MA = CHNH) film. Two-dimensional (ZnPc)MA PbI was successfully constructed within the GBs of MAPbI film achieving a GBs suture for passivating the defects in GBs. Time-resolved photoluminescence showed that the modification increased the decay time from 44 to 57 ns indicating the passivation of GBs reduces trap-assisted recombination. The PSCs with modified perovskite exhibited increased photovoltage, and the best efficiency was improved up to 20.3%. More importantly, the long-term stability of the responding PSCs against humidity and heating was further improved unprecedentedly. Moreover, the modified MAPbI films revealed a self-repairing capability under mild heating. This work provided a novel insight into ongoing fabrication of efficient and stable PSCs by the efficient GBs suture with low-cost phthalocyanine.
Long-term thermal stability is one limiting factor that impedes the commercialization of the perovskite solar cell. Inspired by our prior results from machine learning, we discover that coating a thin layer of 4,4′-dibromotriphenylamine (DBTPA) on top of a CH 3 NH 3 PbI 3 layer can improve the stability of resultant solar cells. The passivated devices kept 96% of the original power conversion efficiency for 1000 h at 85 °C in a N 2 atmosphere without encapsulation. Near-ambient pressure X-ray photoelectron spectroscopy (XPS) was employed to investigate the evolution of the composition and evaluate thermal and moisture stability by in situ studies. A comparison between pristine MAPbI 3 films and DBTPA-treated films shows that the DBTPA treatment suppresses the escape of iodide and methylamine up to 150 °C under 5 mbar humidity. Furthermore, we have used attenuated total reflection Fourier transform infrared and XPS to probe the interactions between DBTPA and MAPbI 3 surfaces. The results prove that DBTPA coordinates with the perovskite by Lewis acid−base and cation−π interaction. Compared with the 19.9% efficiency of the pristine sample, the champion efficiency of the passivated sample reaches 20.6%. Our results reveal DBTPA as a new post-treating molecule that leads not only to the improvement of the photovoltaic efficiency but also thermal and moisture stability.
In this work we have successfully prepared two lead-doped titanium-oxo clusters with core structures that resemble isolated perovskite PbTiO 3 species. In the obtained highly symmetric Pb 8 Ti 7 -oxo cluster, the central TiO 6 octahedra are orthogonally extended to adjacento ctahedra throughc orner-sharingandt he eight dopant lead ions form ac ubic arrangement, making it the first molecular model of perovskite PbTiO 3 .M oreover,t he clusters readily dissolved in chloroform and showedh ighs olution stability, as confirmed by MALDI-TOF MS measurements. Based on such solution processability,t hey can be easily spin-coatedt of orm homogeneous films, whichw ere employed as electron-transport materials in perovskite solar cells to give an averagep ower conversion efficiency of around 15 %a nd improvedd evice stability. This newly developed bottom-up cluster assembly method provides an efficienta pproach to the construction of atomically precise modelso fp erovskite metal oxidesa s well as potential molecular tools to extendt heir applications.Ap re-designed pattern was etched on an FTO glass substrate with dimensions of 2.0 cm 2.0 cm by using al aser etch instrument (instrument type JW-20W-KS). The FTO glass substrate was cleaned by ultrasonication for 10 min in ab ath of acetone, ultrapure water,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.