Controlling traps and structural defects in perovskite absorber layers is crucial for enhancing both the device efficiency and long-term stability of perovskite solar cells (PSCs). Here we demonstrate the modification of perovskite films by introducing low-cost green polymers, polysuccinimide (PSI) and polyasparagine (PASP), into the perovskite layer. Structural, morphological and optoelectronic properties of polymer-modified perovskite films were probed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The incorporation of PSI triggers interactions between the polymer and perovskite, leading to the passivation of surface defects at the grain boundaries and improved morphology of perovskite films. This defect passivation boosted PSC performance, providing power conversion efficiency (PCE) values up to 20.1%. An optimal polymer concentration of 0.1 mg/mL in the perovskite precursor solution was identified for an improvement in the photovoltaic performance. It was shown that the primary factor leading to the observed enhancement in the power conversion efficiency for PSI-modified PSCs is the increase in the lifetime of charge carriers due to the efficient passivation of surface defects and suppression of recombination losses. Additionally, PSI-modified PSCs demonstrated enhanced stability, retaining over 80% of their initial efficiency after 40 days of storage under ambient conditions without encapsulation. The obtained results highlight the effectiveness of green polymer additives in passivating surface defects in perovskite films and provide a viable approach for improving the stability and performance of perovskite solar cells.

The product of ozonolysis, glycero-(9,10-trioxolane)-trioleate (ozonide of oleic acid triglyceride, [OTOA]), was incorporated into polylactic acid/polycaprolactone (PLA/PCL) blend films in the amount of 1, 5, 10, 20, 30 and 40% w/w. The morphological, mechanical, thermal and antibacterial properties of the biodegradable PLA/PCL films after the OTOA addition were studied. According to DSC and XRD data, the degree of crystallinity of the PLA/PCL + OTOA films showed a general decreasing trend with an increase in OTOA content. Thus, a significant decrease from 34.0% for the reference PLA/PCL film to 15.7% for the PLA/PCL + 40% OTOA film was established using DSC. Observed results could be explained by the plasticizing effect of OTOA. On the other hand, the PLA/PCL film with 20% OTOA does not follow this trend, showing an increase in crystallinity both via DSC (20.3%) and XRD (34.6%). OTOA molecules, acting as a plasticizer, reduce the entropic barrier for nuclei formation, leading to large number of PLA spherulites in the plasticized PLA/PCL matrix. In addition, OTOA molecules could decrease the local melt viscosity at the vicinity of the growing lamellae, leading to faster crystal growth. Morphological analysis showed that the structure of the films with an OTOA concentration above 20% drastically changed. Specifically, an interface between the PLA/PCL matrix and OTOA was formed, thereby forming a capsule with the embedded antibacterial agent. The moisture permeability of the resulting PLA/PCL + OTOA films decreased due to the formation of uniformly distributed hydrophobic amorphous zones that prevented water penetration. This architecture affects the tensile characteristics of the films: strength decreases to 5.6 MPa, elastic modulus E by 40%. The behavior of film elasticity is associated with the redistribution of amorphous regions in the matrix. Additionally, PLA/PCL + OTOA films with 20, 30 and 40% of OTOA showed good antibacterial properties on Pseudomonas aeruginosa, Raoultella terrigena (Klebsiella terrigena) and Agrobacterium tumefaciens, making the developed films potentially promising materials for wound-dressing applications.

Hybrid organic-inorganic perovskite solar cells (PSCs) have attracted significant interest owing to their high power conversion efficiency (PCE) and low cost. Moreover, PSCs demonstrate high performance under low light illumination without significant reduction in PCE. However, photovoltaic properties of PSCs under low light conditions are rarely reported. Here, the potential of planar PSCs for efficient performance under low illuminance conditions was investigated. Planar perovskite solar cells with FTO/c-TiO₂/c-SnO₂/CH₃NH₃PbI₃/Spiro-MeOTAD/Au architecture were studied under variable illumination intensities in the range of 10 – 1000 W/m². Significant enhancement in PCE up to 18.4% was observed for planar PSCs under low light conditions (<100 W/m²), as compared to the 16% PCE value obtained under AM1.5 illumination. This was attributed to the decreased charge accumulation at the ETL/perovskite interface and increased charge collection efficiency under low light illumination. PSCs performance was additionally studied under artificial LED lighting (5500K, 1000 lux) and the PCE values exceeding 24% were obtained. The results of this work verify excellent low-light performance of planar PSCs and provide the possibility for their application as power sources for various low-power wireless devices (sensors, detectors, Internet of Things devices, etc.).

Glycerol-(9,10-trioxolane) trioleate (OTOA) is a promising material that combines good plasticizing properties for PLA with profound antimicrobial activity, which makes it suitable for application in state-of-the-art biomedical and packaging materials with added functionality. On the other hand, application of OTOA in PLA-based antibacterial materials is hindered by a lack of knowledge on kinetics of the OTOA release. In this work, the release of glycero-(9,10-trioxolane) trioleate (OTOA) from PLA films with 50% OTOA content was studied during incubation in normal saline solution, and for the first time, the kinetics of OTOA release from PLA film was evaluated. Morphological, thermal, structural and mechanical properties of the PLA + 50% OTOA films were studied during incubation in normal saline and corresponding OTOA release using differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and mechanical tests. It was confirmed by DSC and XRD that incubation in the saline solution and corresponding OTOA release from PLA film does not lead to significant changes in the structure of the polymer matrix. Thus, the formation of more disturbed α’ crystalline phase of PLA due to partial hydrolysis of amorphous zones and/or most unstable crystallites in the PLA/OTOA semi-crystalline structure was observed. The degree of crystallinity of PLA + OTOA film was also slightly increased at the prolonged stages of OTOA release. PLA + 50% OTOA film retained its strength properties after incubation in normal saline, with a slight increase in the elastic modulus and tensile strength, accompanied by a significant decrease in relative elongation at break. The obtained results showed that PLA + 50% OTOA film could be characterized by sustained OTOA release with the amount of released OTOA exceeding 50% of the initial content in the PLA film. The OTOA release profile was close to zero-order kinetics, which is beneficial in order to provide stable drug release pattern. Developed PLA + 50% OTOA films showed a strong and stable antibacterial effect against Raoultella terrigena and Escherichia coli, bacterial strains with multidrug resistance behavior. The resulting PLA + OTOA films could be used in a variety of biomedical and packaging applications, including wound dressings and antibacterial food packaging.

The product of ozonolysis, Glycero-(9,10-trioxolane)-trioleate (ozonide of oleic acid triglyceride, [OTOA]), was incorporated into polylactic acid/polycaprolactone (PLA/PCL) blend films in the amount of 1, 5, 10, 20, 30, and 40% w/w. The morphological, mechanical, thermal and antibacterial properties of the biodegradable blend after the OTOA addition were studied. According to DSC and XRD data, the crystallinity degree of PLA/PCL+OTOA films tended to decrease with increase in OTOA content that could be explained by its plasticizing effect. Morphological analysis showed that the structure of the films with the OTOA concentration above 20% drastically changed. Specifically, the interface between the PLA/PCL matrix and OTOA was formed, thereby forming a capsule with the embedded antibacterial agent. The moisture permeability of the resulting PLA/PCL+OTOA films decreased due to the formation of uniformly distributed hydrophobic amorphous zones that prevents water penetration. This architecture affects the tensile characteristics of the films: strength decreases to 5.6 MPa, elastic modulus E by 40%. The behavior of film elasticity is associated with the redistribution of amorphous regions in the matrix. Additionally, PLA/PCL+OTOA films with 20, 30 and 40% of OTOA showed good antibacterial properties on Pseudomonas aeruginosa, Raoultella terrigena (Klebsiella terrigena) and Agrobacterium tumefaciens. Developed PLA/PCL+OTOA films could be used as packaging materials and wound dressings. By variation of the OTOA content, it is possible to tailor the physical-chemical and antibacterial properties of the developed films for various applications.