In bulk heterojunction (BHJ) organic solar cells (OSCs) employing perylene diimide (PDI)-based non-fullerene acceptors, excessive intermolecular interactions among PDI units lead to severe aggregation and pronounced donor–acceptor phase separation, both of which critically limit device performance. To address these issues, numerous structurally engineered PDI derivatives have been developed. In particular, twisted multi-PDI architectures designed to suppress intermolecular aggregation have shown improved morphological control; however, such twisted structures are often highly amorphous, which reduces electron-transport efficiency and constrains OSC performance. In this work, we introduce a mixed-acceptor strategy combining a twisted PDI dimer (SF-PDI₂) with a planar monomeric PDI (m-PDI) to balance aggregation and morphological uniformity. Ternary blend OSCs consisting of PTB7-Th as the donor and these two PDI acceptors exhibit systematic performance variations depending on their relative ratios. At the optimized composition (SF-PDI₂:m-PDI = 90:10 by weight), the device outperforms single-acceptor systems, which is attributed to controlled aggregation arising from the complementary structural features of the two PDI acceptors. This study demonstrates that combining mixed PDI acceptors with similar molecular moieties enables precise control of aggregation, improving both morphology and photovoltaic performance.

The development of sustainable alternatives to fossil-based feedstocks is a global priority in light of climate change and resource depletion. Seaweeds, particularly green seaweeds, represent promising candidates for biorefinery applications due to their rapid growth, high carbohydrate content, and non-competition with arable land. In this study, the feasibility of lactic acid production from acid hydrolysates of the green seaweed Ulva pertusa was systematically investigated. Proximate composition analysis revealed that dried Ulva pertusa contained 52.3% carbohydrates, highlighting its suitability as a fermentation substrate. Acid hydrolysis with dilute sulfuric acid released 23.8 g of fermentable monosaccharides per 100 g of biomass, with L-rhamnose and D-glucose as the predominant sugars. Fermentation experiments were conducted using five Lactobacillus strains (L. casei, L. plantarum, L. brevis, L. salivarius, and L. rhamnosus). Among these, L. rhamnosus and L. salivarius achieved the highest lactic acid yields (0.66 g g⁻¹), followed by L. plantarum (0.63 g g⁻¹), whereas L. casei and L. brevis exhibited comparatively lower yields (0.46 and 0.39 g g⁻¹, respectively). Time-course analysis demonstrated that the superior strains reached maximum productivity within 9 h, significantly faster than typical lignocellulosic feedstocks such as corn stover, which require extensive pretreatment and longer fermentation times. Furthermore, the mineral-rich composition of Ulva pertusa (notably Mg²⁺ and Ca²⁺) provided intrinsic nutrients that supported microbial growth, thereby reducing the requirement for external supplementation. Comparative evaluation with lignocellulosic hydrolysates confirmed that Ulva pertusa offers higher efficiency, faster kinetics, and lower process complexity. To our knowledge, this work represents the first comprehensive assessment of multiple Lactobacillus strains for lactic acid production from Ulva pertusa hydrolysates. The findings highlight the unique advantages of green seaweeds as a sustainable biomass resource and contribute to the advancement of marine biomass-based biorefineries. Future studies should focus on improving the utilization of non-fermentable sugars, optimizing fermentation strategies, and evaluating techno-economic feasibility on an industrial scale.

Seaweeds are promising third-generation biomass for biobased chemicals, yet their use for lactic acid (LA) production remains underexplored. We evaluated LA production from the dilute-acid hydrolysate of the aquacultured green alga Capsosiphon fulvescens (C.Agardh) Setchell & N.L. Gardner. The dried biomass contained 53.4% carbohydrate (dry-weight basis). HPLC showed a monosaccharide profile enriched in L-rhamnose and D-xylose, with lower levels of D-mannose, D-glucose, D-glucuronolactone, and D-glucuronic acid. Batch fermentations with three Lactobacillus strains revealed clear strain-dependent kinetics and carbon partitioning. Maximum LA titers/yields (time at maximum) were 2.0 g L⁻¹/0.49 g g⁻¹ at 9 h for L. rhamnosus, 2.3 g L⁻¹/0.30 g g⁻¹ at 36 h for L. casei, and 2.8 g L⁻¹/0.23 g g⁻¹ at 48 h for L. brevis; L. rhamnosus achieved the highest yield on sugars consumed, whereas L. brevis reached the highest titer by utilizing a broader sugar spectrum, notably xylose; L. casei showed intermediate performance with limited xylose use. Co-products included acetic and succinic acids (major) and trace 1,2-propanediol and acetaldehyde, consistent with flux through Embden–Meyerhof–Parnas versus phosphoketolase pathways. These results demonstrate that C. fulvescens hydrolysate is a viable marine feedstock for LA production and highlight practical levers—expanding pentose/uronic-acid catabolism in high-yield strains and tuning pretreatment severity—to further improve both yield and titer.