RESUMO
With the rapid development in perovskite solar cell (PSC), high efficiency has been achieved, but the long-term operational stability is still the most important challenges for the commercialization of this emerging photovoltaic technology. So far, bi-dopants lithium bis(trifluoromethylsulfonyl)-imide (Li-TFSI)/4-tert-butylpyridine (t-BP)-doped hole-transporting materials (HTM) have led to state-of-the art efficiency in PSCs. However, such dopants have several drawbacks in terms of stability, including the complex oxidation process, undesirable ion migration and ultra-hygroscopic nature. Herein, a fluorine-containing organic Lewis acid dopant bis(pentafluorophenyl)zinc (Zn-FP) with hydrophobic property and high migration barrier has been employed as a potential alternative to widely employed bi-dopants Li-TFSI/t-BP for poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). The resulting Zn-FP-based PSCs achieve a maximum PCE of 20.34 % with hysteresis-free current density-voltage (J-V) scans. Specifically, the unencapsulated device exhibits a significantly advanced of operational stability under the International Summit on Organic Photovoltaic Stability protocols (ISOS-L-1), maintaining over 90 % of the original efficiency after operation for 1000â h under continuous 1-sun equivalent illumination in N2 atmosphere in both forward and reverse J-V scan.
RESUMO
Conventional electrochromic devices with a sandwich structure consist of multiple interfaces, which enhance electron trapping on the interfaces. Furthermore, crack generation in the electrochromic layer is inevitable due to repeated ion insertion and extraction during the service process. These problems increase the fabrication complexity and lead to poor performance and stability, which are severely limiting and prime concerns for the future development of the electrochromism field. Here, a strategy of synthesizing an all-in-one self-healing electrochromic material, TAFPy-MA, is presented, which has been utilized for the fabrication of a high-reliability, large-scale, and easy-assembly smart electrochromic window. The all-in-one self-healing electrochromic material can undergo in situ redox reactions with Li+ ions to reduce resistance transfer and avoid interface obstacles, and the reversible Diels-Alder cross-linking network structure can heal the cracks to improve the reliability of the electrochromic layer. High ion diffusivity (1.13 × 10-5 cm2 s-1), rapid color switching (3.9/3.7 s), high coloration efficiency (413 cm2 C-1), excellent stability (sustains 88.7% after 1000 cycles) and reliability (crack can be healed in 110 s), and large-scale smart windows (30 × 35 cm2) are achieved using the all-in-one electrochromic material, which exhibits fascinating and promising features for a wide range of applications in buildings, airplanes, etc.
RESUMO
Animals such as chameleons possess a natural ability to adjust their skin color as a preventive measure to deter any potential threat and to self-heal damaged skin tissues. Inspired by this, we present here a copolymer film possessing biomimetic properties that simultaneously integrates electrochromic triphenylamine and self-healing Diels-Alder groups. The flexible and stretchable copolymer film acts like natural chameleon skin, which exhibits significant color variation and also possesses excellent self-healing properties. These remarkable features make it a promising material for overcoming the crack-generation issue inherited by conventional biomimetic chameleon skin. Moreover, a flexible and wearable skin device based on the copolymer film with silver fabric as a electrode has also been fabricated. The electrochromic and self-healing properties were verified for the copolymer film, and it has been elucidated that the intelligent biomimetic "chameleon skin" was a new step toward the development of highly advanced biomimetic materials and devices.