Search

Herein, we report on the family of fullerene derivatives F2-F6 as electron transport materials (ETMs) in inverted perovskite solar cells (PSCs). According to the results, F2 and F4 have power conversion efficiencies (PCE) of 17.2% and 16.7%, respectively, which indicates better performance than conventional ETM (PC61BM). Utilizing infrared scattering scanning near-field optical microscopy (IR s-SNOM), we ascertained that F2 and F4 demonstrate exceptional uniformity and are devoid of defects. This characteristic contributes to a reduction in trap density and charge recombination in PSCs, ultimately enhancing device efficiency and mitigating hysteresis. Above all, F2 showed no signs of deterioration when the PSCs were exposed to 45 ± 5% relative humidity for 1000 h. Our research provides an innovative viewpoint on how to create novel fullerene compounds that enhance efficiency and stability of PSCs. [ABSTRACT FROM AUTHOR]

The high power-conversion efficiencies of hybrid perovskite solar cells encourage many researchers. However, their limited photostability represents a serious obstacle to the commercialization of this promising technology. Herein, we present an efficient method for improving the intrinsic photostability of a series of commonly used perovskite material formulations such as MAPbI3, FAPbI3, Cs0.12FA0.88PbI3, and Cs0.10MA0.15FA0.75PbI3 through modification with octenidine dihydroiodide (OctI2), which is a widely used antibacterial drug with two substituted pyridyl groups and two cationic centers in its molecular framework. The most impressive stabilizing effects were observed in the case of FAPbI3 and Cs0.12FA0.88PbI3 absorbers that were manifested in significant suppression or even blocking of the undesirable perovskite films' recrystallization and other decomposition pathways upon continuous 110 mW/cm2 light exposure. The achieved material photostability—within 9000 h for the Oct(FA)n−1PbnI3n+1 (n = 40–400) and 20,000 h for Oct(Cs0.12FA0.88)n−1PbnI3n+1 (where n = 40–400) formulations—matches the highest values ever reported for complex lead halides. It is important to note that the stabilizing effect is maintained when OctI2 is used only as a perovskite surface-modifying agent. Using a two-cation perovskite composition as an example, we showed that the performances of the solar cells based on the developed Oct(Cs0.12FA0.88)399Pb400I1201 absorber material are comparable to that of the reference devices based on the unmodified perovskite composition. These findings indicate a great potential of the proposed approach in the design of new highly photostable and efficient light absorbers. We believe that the results of this study will also help to establish important guidelines for the rational material design to improve the operational stability of perovskite solar cells. [ABSTRACT FROM AUTHOR]

Perovskite solar cells represent a highly promising third-generation photovoltaic technology. However, their practical implementation is hindered by low device operational stability, mostly related to facile degradation of the absorber materials under exposure to light and elevated temperatures. Improving the intrinsic stability of complex lead halides is a big scientific challenge, which might be addressed using various "molecular modifiers". These modifiers are usually represented by some additives undergoing strong interactions with the perovskite absorber material, resulting in enhanced solar cell efficiency and/or operational stability. Herein, we present a derivative of 1,4,6,10-tetraazaadamantane, NAdCl, as a promising molecular modifier for lead halide perovskites. NAdCl spectacularly improved both the thermal and photochemical stability of methylammonium lead iodide (MAPbI3) films and, most importantly, prevented the formation of metallic lead Pb0 as a photolysis product. NAdCl improves the electronic quality of perovskite films by healing the traps for charge carriers. Furthermore, it strongly interacts with the perovskite framework and most likely stabilizes undercoordinated Pb2+ ions, which are responsible for Pb0 formation under light exposure. The obtained results feature 1,4,6,10-tetraazaadamantane derivatives as highly promising molecular modifiers that might help to improve the operational lifetime of perovskite solar cells and facilitate the practical implementation of this photovoltaic technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • The modification of perovskites by partial replacement of Pb2+ with Dy2+ was explored. • Incorporation of Dy2+ strongly enhanced resistance of perovskite films to gamma rays. • The presence of Dy2+ suppressed metallic lead Pb0 formation upon radiolysis. • Dy modification improved the tolerance of perovskite films to 8.5 MeV electron beams. • Excellent radiation hardness of Dy-loaded absorbers points to aerospace applications. Continuously growing evidence of the excellent radiation hardness of perovskite solar cells stimulates their intense exploration in the context of potential aerospace applications. However, there is still a very limited understanding of the fundamental aspects such as the mechanisms of the interaction of complex lead halides with different types of ionizing radiation and associated aging pathways, even though this knowledge is essentially important for the development of new materials with improved properties. Herein, we made one of the first steps to fill this gap through a systematic study of the aging behavior of two perovskite absorber materials under exposure to three different stressors: 60Co gamma-rays, 8.5 MeV electron fluences, and light. The application of a set of complementary spectroscopy and microscopy techniques allowed us to identify and compare perovskite degradation pathways caused by each type of the ionizing radiation. In particular, radiation-induced phase segregation with the formation of δ-phases of CsPbI 3 and FAPbI 3 appears to be a common route in the case of double cation perovskites. Most importantly, we have revealed that the incorporation of dysprosium cations as a replacement of 1 % of Pb2+ ions in the Cs 0.12 FA 0.88 Pb 0.99 Dy 0.01 I 3 material formulation results in a remarkably improved radiation hardness: this modification blocks the formation of metallic lead and strongly suppresses segregation of Cs-rich and FA-rich phases in perovskite films under exposure to gamma rays or high-energy electrons. Thus, these results open up a promising research direction for designing radiation-resistant perovskite absorbers through rational compositional engineering. [ABSTRACT FROM AUTHOR]

A series of four new oligomeric derivatives of NFA , NFA(S) , NFA(Se) and NFA(N) with terminal perylene diimide groups modified with heteroatoms of S, Se, and N, were successfully synthesized and fully characterized by a variety of physicochemical methods. Due to deep LUMO levels, all compounds have an electron-acceptor character, which allows them to perform as electron transport compounds in perovskite solar cells of p-i-n architecture. The highest efficiency of 17.23 % was delivered by the solar cells with NFA(Se) electron transporting layer. [Display omitted] • A series of new oligomers with terminal perylene diimide groups modified with heteroatoms of S, Se, and N, were synthesized. • Optical and electronic properties of the new compounds were studied. • All the compounds were studied as new type materials for electron transport layer for perovskite solar cells. • The highest efficiency of 17.23 % was delivered by the solar cells with NFA(Se) electron transporting layer. [ABSTRACT FROM AUTHOR]