2D Ti 3 C 2 T x MXene, possessing facile preparation, high electrical conductivity, flexibility, and solution processability, shows good application potential for enhancing device performance of perovskite solar cells (PVSCs). In this study, tetrabutylammonium bromide functionalized Ti 3 C 2 T x (TBAB-Ti 3 C 2 T x ) is developed as cathode buffer layer (CBL) to regulate the PCBM/Ag cathode interfacial property for the first time. By virtue of the charge transfer from TBAB to Ti 3 C 2 T x demonstrated by electron paramagnetic resonance and density functional theory, the TBAB-Ti 3 C 2 T x CBL with high electrical conductivity exhibits significantly reduced work function of 3.9 eV, which enables optimization of energy level alignment and enhancement of charge extraction. Moreover, the TBAB-Ti 3 C 2 T x CBL can effectively inhibit the migration of iodine ions from perovskite layer to Ag cathode, which synergistically suppresses defect states and reduce charge recombination. Consequently, utilizing MAPbI 3 perovskite without post-treatment, the TBAB-Ti 3 C 2 T x based device exhibits a dramatically improved power conversion efficiency of 21.65% with significantly improved operational stability, which is one of the best efficiencies reported for the devices based on MAPbI 3 /PCBM with different CBLs. These results indicate that TBAB-Ti 3 C 2 T x shall be a promising CBL for high-performance inverted PVSCs and inspire the further applications of quaternary ammonium functionalized MXenes in PVSCs.

The impact of a light-transforming covering on photosynthetic activity and growth processes in lettuce and white cabbage plants grown in a glass greenhouse was studied. Plants were covered with agrotextile, a polypropylene (PP) nonwoven spunbond coated with polylactide varnish containing a new organic luminophore (LUM), which absorbs sunlight mainly in the 460–560 nm region and efficiently reradiates it in the red spectral region with a maximum at 660 nm. For comparison, simultaneously two references agrotextiles without LUM or containing a non-luminescent chromophore (ABS) with an absorption spectrum close to that of LUM were as well investigated. The use of the agrotextile with LUM resulted in a significant increase in total crude aboveground biomass for 32-, 33-, and 43-day-old plants on the average by 20–40%, and the photosynthesis rate increased on the average by 30–40% compared to the agrotextile without LUM. The use of the agrotextile with ABS mimicking the absorption of LUM also did not reveal a significant impact on photosynthesis and biomass accumulation in the plants as compared to the reference agrotextile coated only with the polylactide varnish. At the same time, the photosystem II activity (Fv/Fm and F′v/F′m quantum yields) was nearly the same in all experiments. When plants were grown under the light-converting agrotextile, the luminescent component of the converted light in the red spectrum region led to an increase in plant growth and photosynthesis rate, which is a fundamentally new result. Possible reasons for the stimulation of growth and photosynthesis due to the redistribution of the light spectral composition were analyzed. The use of covering materials containing luminophores similar to LUM can be promising in agrobiotechnology not only for green and vegetable crops but also for other field and greenhouse crops and various fruit bushes and trees.

Full characterization of nanostructured organosilicon luminophores NOL4 and NOL5 based on the donor 2,2'-bithiophene and acceptor 1,4-bis(2,2 ′ -bithiophene-5-yl)benzene units in dilute solutions and thin films by UV-Vis spectroscopy, DSC, TGA and X-ray techniques was reported. It was found that usage of these molecules as dopants (10-20 wt%) to the electroactive polyfluorene host in organic light-emitting devices (OLEDs) leads to the efficient spectral long wavelength shifting of the electroluminescence and an increase of the OLED performance as compared to the devices based on pristine polyfluorene, NOL4 and NOL5.

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