Tuning the molecular ordering of COi8DFIC from flat-on and edge-on lamellae to Hand J-type p-p stacking results in broadened absorption spectrum and fine phase separation with the electron donor PTB7-Th, which promotes efficient exciton dissociation at the donor/acceptor interface together with enhanced and balanced carrier mobility, and leads to an unprecedented PCE of 13.8% of singlejunction, binary PTB7-Th:COi8DFIC solar cell.

Fluorination of conjugated molecules has been established as an effective structural modification strategy to influence properties, and has attracted extensive attention in organic solar cells (OSCs). Here, we have investigated optoelectronic and photovoltaic property changes of OSCs made of polymer donors with the non-fullerene acceptors (NFAs) ITIC and IEICO and their fluorinated counterparts IT-4F and IEICO-4F. Device studies show that fluorinated NFAs lead to reduced Voc but increased Jsc and FF, and therefore the ultimate influence to efficiency depends on the compensation of Voc loss and gains of Jsc and FF. Fluorination lowers energy levels of NFAs, reduces their electronic bandgaps and red-shifts the absorption spectra. The impact of fluorination on the molecular order depends on the specific NFA, with the conversion of ITIC to IT-4F reduces structural order, which can be reversed after blending with the donor PBDB-T. Contrastingly, IEICO-4F presents stronger p-p stacking after fluorination from IEICO, and this is further strengthened after blending with the donor PTB7-Th. The photovoltaic blends universally present a donor-rich surface region which can promote charge transport and collection towards anode in inverted OSCs. The fluorination of NFAs, however, reduces the fraction of donors in this donor-rich region, consequently encourage the intermixing of donor/acceptor for efficient charge generation.

The development of scalable deposition methods for perovskite solar cell materials is critical to enable the commercialization of this nascent technology. Herein, we investigate the use and processing of nanoparticle SnO2 films as electron transport layers in perovskite solar cells and develop deposition methods for ultrasonic spray coating and slot-die coating, leading to photovoltaic device efficiencies over 19%. The effects of postprocessing treatments (thermal annealing, UV ozone, and O2 plasma) are then probed using structural and spectroscopic techniques to characterize the nature of the np-SnO2/perovskite interface. We show that a brief “hot air flow” method can be used to replace extended thermal annealing, confirming that this approach is compatible with high-throughput processing. Our results highlight the importance of interface management to minimize nonradiative losses and provide a deeper understanding of the processing requirements for large-area deposition of nanoparticle metal oxides.

Self-assembled monolayers (SAMs) are becoming widely utilized as hole-selective layers in high-performance p-i-n architecture perovskite solar cells. Ultrasonic spray coating and airbrush coating are demonstrated here as effective methods to deposit MeO-2PACz; a carbazole-based SAM. Potential dewetting of hybrid perovskite precursor solutions from this layer is overcome using optimized solvent rinsing protocols. The use of air-knife gas-quenching is then explored to rapidly remove the volatile solvent from an MAPbI 3 precursor film spray-coated onto an MeO-2PACz SAM, allowing fabrication of p-i-n devices with power conversion efficiencies in excess of 20%, with all other layers thermally evaporated. This combination of deposition techniques is consistent with a rapid, roll-to-roll manufacturing process for the fabrication of large-area solar cells.

This is a repository copy of Correlating the electron-donating core structure with morphology and performance of carbon-oxygen-bridged ladder-type non-fullerene acceptor based organic solar cells.

This is a repository copy of Regulating the morphology of fluorinated non-fullerene acceptor and polymer donor via binary solvent mixture for high efficiency polymer solar cells.

BACKGROUND The healthcare environment is recognized as a source for healthcare-acquired infection. Because cleaning practices are often erratic and always intermittent, we hypothesize that continuously antimicrobial surfaces offer superior control of surface bioburden. OBJECTIVE To evaluate the impact of a photocatalytic antimicrobial coating at near-patient, high-touch sites in a hospital ward. SETTING The study took place in 2 acute-care wards in a large acute-care hospital. METHODS A titanium dioxide-based photocatalytic coating was sprayed onto 6 surfaces in a 4-bed bay in a ward and compared under normal illumination against the same surfaces in an untreated ward: right and left bed rails, bed control, bedside locker, overbed table, and bed footboard. Using standardized methods, the overall microbial burden and presence of an indicator pathogen (Staphylococcus aureus) were assessed biweekly for 12 weeks. RESULTS Treated surfaces demonstrated significantly lower microbial burden than control sites, and the difference increased between treated and untreated surfaces during the study. Hygiene failures (>2.5 colony-forming units [CFU]/cm2) increased 2.6% per day for control surfaces (odds ratio [OR], 1.026; 95% confidence interval [CI], 1.009-1.043; P=.003) but declined 2.5% per day for treated surfaces (OR, 0.95; 95% CI, 0.925-0.977; P<.001). We detected no significant difference between coated and control surfaces regarding S. aureus contamination. CONCLUSION Photocatalytic coatings reduced the bioburden of high-risk surfaces in the healthcare environment. Treated surfaces became steadily cleaner, while untreated surfaces accumulated bioburden. This evaluation encourages a larger-scale investigation to ascertain whether the observed environmental amelioration has an effect on healthcare-acquired infection. Infect Control Hosp Epidemiol 2018;39:398-404.

Organic-inorganic metal halide perovskites are rapidly approaching state-of-the-art silicon solar cells, with bestperforming devices now reaching power conversion efficiencies (PCEs) of 25.7%. [1] Although stability remains a challenge for perovskite solar cells (PSCs), their solution-processability represents a major advantage. Techniques such as blade coating, [2] slot-die coating, [3] and spray coating [4] are compatible with roll-to-roll (R2R) processing, which-in principleshould allow much higher throughput speeds than existing silicon solar technologies. However, the lengthy annealing times used to crystallize the perovskite active layer reduce the maximum theoretical web speeds that could be achieved in a practical manufacture process.In 2020, Rolston et al. demonstrated the highest coating speeds of any scalable PSC processing technologies, achieving production speeds of >12 m min −1 . [5] Spray coating was combined with an atmospheric plasma postprocessing route, [6] creating PSC devices and modules with a PCE of 18% and 15.5%, respectively. Critically, these were fabricated without annealing the perovskite layer. At these speeds, the module cost is expected to be fully competitive with Si. [7] In contrast, the calculated throughput rate for spin-coated PSCs incorporating a 10-min anneal is just 0.017 m min −1 ; a rate prohibitive for commercialization. Furthermore, high temperature processing steps increase device manufacturing costs through increased utility costs and reduced throughput. [8] High process temperatures are also incompatible with many sensitive flexible (polymeric) substrates that are expected to be important in "Internet of Things" applications. [9,10] This growing market is expected to reduce the initial investment and barrier to market entry for perovskites by an order of magnitude. [11] Many approaches to create "annealing-free" PSCs have been demonstrated. For example, thermal evaporation of the perovskite layer without any post-annealing treatments can be used to realize devices having reasonable PCEs of up to 15.7%. [12,13] Zhou et al. demonstrated devices with a PCE of 15.7% for MAPbI 3 (where MA is methylammonium) films grown via electrochemical fabrication. [14] The use of antisolvent High temperature post-deposition annealing of hybrid lead halide perovskite thin films-typically lasting at least 10 min-dramatically limits the maximum roll-to-roll coating speed, which determines solar module manufacturing costs. While several approaches for "annealing-free" perovskite solar cells (PSCs) have been demonstrated, many are of limited feasibility for scalable fabrication. Here, this work has solvent-engineered a high vapor pressure solvent mixture of 2-methoxy ethanol and tetrahydrofuran to deposit highly crystalline perovskite thin-films at room temperature using gas-quenching to remove the volatile solvents. Using this approach, this work demonstrates p-i-n devices with an annealing-free MAPbI 3 perovskite layer achieving stabilized power conversion efficiencies (PCEs) of up to 1...