Flexible, Transparent, and Bifacial Perovskite Solar Cells and Modules Using the Wide-Band Gap FAPbBr3 Perovskite Absorber.

Perovskite solar cells (PSCs) offer impressive performance and flexibility, thanks to their simple, low-temperature deposition methods. Their band gap tunability allows for a wide range of applications, transitioning from opaque to transparent devices. This study introduces the first flexible, bifacial PSCs using the FAPbBr3 perovskite. We investigated the impact of optimizing electron and hole transport layers on the cells' bifaciality, transparency, and stability. PSCs achieved a maximum power conversion efficiency (PCE) of 6.8 and 18.7% under 1 sun and indoor light conditions (1200 lx), respectively, showing up to 98% bifaciality factor and an average visible transmittance (AVT) of 55%. Additionally, a P1-P2-P3 laser ablation scheme has been developed on the flexible poly(ethylene terephthalate) (PET) substrate for perovskite solar modules showing a PCE of 4.8% and high geometrical fill factor (97.8%). These findings highlight the potential of flexible, bifacial PSCs for diverse applications such as building-integrated photovoltaics (BIPV), agrivoltaics, automotive technology, wearable sensors, and Internet of things (IoT).

Infantile nystagmus syndrome: An observational, retrospective, multicenter study.

SIGNIFICANCE: This multicenter study assessed clinical and psychological aspects of infantile nystagmus syndrome (INS) focusing on its management and nonsurgical treatment. PURPOSE: This study aimed to assess clinical features, management, relationship life, and psychological impact in a group of patients with nystagmus onset in pediatric age. METHODS: This observational study included patients diagnosed with INS referred to two Italian centers from January 1, 2017, to December 31, 2020. Ophthalmologic and orthoptic features and impact of visual function on quality of life, according to nystagmus-specific nystagmus quality of life questionnaire, were analyzed within the overall sample and in any of INS subgroups. RESULTS: Forty-three patients were included; 65.1% of them had idiopathic INS (IINS), and 34.9% had INS associated with ocular diseases (INSOD). The median age was 15.4 years (interquartile range [IQR], 10.4 to 17.3 years), significantly different between groups (median, 15.8 years among those with IINS vs. 12.3 years among those with INSOD; p<0.001). In the INSOD subgroup, strabismus was significantly more prevalent (93.3 vs. 57.1%; p=0.017). Binocular distance best-corrected visual acuity in primary position was significantly higher in the IINS subsample (p<0.001). Such behavior was further confirmed at anomalous head position evaluation (p<0.001). At near best-corrected visual acuity assessment, differences between groups were more remarkable in primary position (p<0.001) than in anomalous head position. Contrast sensitivity showed significantly higher values in the IINS subgroup (p<0.001). The nystagmus quality of life questionnaire disclosed a significantly lower score in IINS as compared with INSOD (median total score, 90.5 [IQR, 84 to 97] vs. 94 [IQR, 83.0 to 96.5]; p<0.001). CONCLUSIONS: The IINS group showed significantly better ophthalmologic and orthoptic outcomes than the INSOD group. The psychological and quality-of-life impact was instead significantly greater in the IINS group. To the best of our knowledge, this is the first multicenter study investigating the clinical features of IIN and comparing the two main subgroups, IINS and INSOD.

The Effect of Varied Microperimetric Biofeedback Training in Central Vision Loss: A Randomized Trial.

SIGNIFICANCE: This investigation reports for the first time the effects of different microperimetric biofeedback strategies in visually impaired subjects with central field loss. PURPOSE: This study aimed to evaluate the effects of two MP-3 microperimeter biofeedback strategies on the visual performance of subjects with central vision loss. Moreover, changes between the groups were compared to provide indications of practice with biofeedback stimulation in subjects with central vision loss. METHODS: Using simple randomization, 19 participants were trained according to two different biofeedback stimulation approaches using the MP-3 microperimeter. Patients were assigned to two different groups: subjects trained for 2 days a week (group A) and 3 days a week (group B). The patients in each group were randomized to perform a total of 10 or 15 sessions. RESULTS: Fixation stability increased from 4.5 ± 2.8 to 2.3 ± 2.2° 2 and from 8.2 ± 6.9 to 1.4 ± 1° 2 after 2 and 3 weekly biofeedback training sessions, respectively ( P < .05). Biofeedback training induced a significant improvement of 40.7 and 29.4% in reading speed for groups A and B, respectively ( P < .05). A comparison of two weekly biofeedback training sessions with three weekly biofeedback sessions demonstrated greater fixation stability in group B ( P < .05). CONCLUSIONS: This study concludes that a biofeedback intervention is effective in enhancing oculomotor control in patients with central vision loss. In our study, a more intensive biofeedback strategy seemed to produce significantly better results in terms of functional vision parameters.

Progress of Photocapacitors.

In response to the current trend of miniaturization of electronic devices and sensors, the complementary coupling of high-efficiency energy conversion and low-loss energy storage technologies has given rise to the development of photocapacitors (PCs), which combine energy conversion and storage in a single device. Photovoltaic systems integrated with supercapacitors offer unique light conversion and storage capabilities, resulting in improved overall efficiency over the past decade. Consequently, researchers have explored a wide range of device combinations, materials, and characterization techniques. This review provides a comprehensive overview of photocapacitors, including their configurations, operating mechanisms, manufacturing techniques, and materials, with a focus on emerging applications in small wireless devices, Internet of Things (IoT), and Internet of Everything (IoE). Furthermore, we highlight the importance of cutting-edge materials such as metal-organic frameworks (MOFs) and organic materials for supercapacitors, as well as novel materials in photovoltaics, in advancing PCs for a carbon-free, sustainable society. We also evaluate the potential development, prospects, and application scenarios of this emerging area of research.

Efficacy and Patients' Satisfaction with the ORCAM MyEye Device Among Visually Impaired People: A Multicenter Study.

To evaluate usability of and satisfaction with OrCam MyEye, a finger-size wearable assistive technology device for visually impaired during real-world tasks. This prospective multicenter study was conducted on visually impaired people recruited from 5 vision rehabilitation centers. Patients performed real-world tasks such as near and distance reading, money handling, colour identification and face recognition in 2 different scenarios: without using any low vision aid and with OrCam. System Usability Scale (SUS), Patient's Global Impression of Change (PGIC), the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0) and the Psychosocial Impact of Assistive Devices Scale (PIADS) were administered after the use of the OrCam device. Among the 100 participants, use of OrCam MyEye device improved many daily-living tasks (F = 1.67, P < .05), and in particular reading and face recognition. Multivariate logistic regression showed that age and visual field defect explained 89% of the variation in efficacy of the device. Nearly half (45%) of the participants indicated a positive rating with the SUS. The PGIC rates showed a minimal improvement with a mean score of 4.2 (SD:1.8). The most highlighted parameter with the QUEST 2.0 test was "ease of use" in 58% (48 subjects). The PIADS indicator showed that the device positively impacted on the daily-living tasks of users (r2 = 0.72, P < .05). Regression modelling demonstrated a good relation between the questionnaires scores and demographic, disease and visual factors (P < .05). OrCam MyEye allowed visually impaired people to read, handle money and face recognition independently. This device may offer to these subjects to be independent.

Attributes of High-Performance Electron Transport Layers for Perovskite Solar Cells on Flexible PET versus on Glass.

Electron transport layers (ETLs) play a fundamental role in perovskite solar cells (PSCs) through charge extraction. Here, we developed flexible PSCs on 12 different kinds of ETLs based on SnO2. We show that ETLs need to be specifically developed for plastic substrates in order to attain 15% efficient flexible cells. Recipes developed for glass substrates do not typically transfer directly. Among all the ETLs, ZnO/SnO2 double layers delivered the highest average power conversion efficiency of 14.6% (best cell 14.8%), 39% higher than that of flexible cells of the same batch based on SnO2-only ETLs. However, the cells with a single ETL made of SnO2 nanoparticles were found to be more stable as well as more efficient and reproducible than SnO2 formed from a liquid precursor (SnO2-LP). We aimed at increasing the understanding of what makes a good ETL on polyethylene terephthalate (PET) substrates. More so than ensuring electron transport (as seen from on-current and series resistance analysis), delivering high shunt resistances (R SH) and lower recombination currents (I off) is key to obtain high efficiency. In fact, R SH of PSCs fabricated on glass was twice as large, and I off was 76% lower in relative terms, on average, than those on PET, indicating considerably better blocking behavior of ETLs on glass, which to a large extent explains the differences in average PCE (+29% in relative terms for glass vs PET) between these two types of devices. Importantly, we also found a clear trend for all ETLs and for different substrates between the wetting behavior of each surface and the final performance of the device, with efficiencies increasing with lower contact angles (ranging between ∼50 and 80°). Better wetting, with average contact angles being lower by 25% on glass versus PET, was conducive to delivering higher-quality layers and interfaces. This cognizance can help further optimize flexible devices and close the efficiency gap that still exists with their glass counterparts.

Simple and effective deposition method for solar cell perovskite films using a sheet of paper.

Most laboratories employ spin coating with application of antisolvent to achieve high efficiency in perovskite solar cells. However, this method wastes a lot of material and is not industrially usable. Conversely, large area coating techniques such as blade and slot-die require high precision engineering both for deposition of ink and for gas or for electromagnetic drying procedures that replace, out of necessity, anti-solvent engineering. Here we present a simple and effective method to deposit uniform high-quality perovskite films with a piece of paper as an applicator at low temperatures. We fabricated solar cells on flexible PET substrates manually with 11% power conversion efficiency. Deposition after soaking the sheet of paper in a green antisolvent improved the efficiency by 82% compared to when using dry paper as applicator. This new technique enables manual film deposition without any expensive equipment and has the potential to be fully automated for future optimization and exploitation.

Exploring the Infiltration Features of Perovskite within Mesoporous Carbon Stack Solar Cells Using Broad Beam Ion Milling.

Carbon perovskite solar cells (C-PSCs) are a popular photovoltaic technology currently undergoing extensive development on the global research scene. Whilst their record efficiency now rivals that of silicon PV in small-scale devices, C-PSCs still require considerable development to progress to a commercial-scale product. This study is the first of its kind to use broad beam ion milling for C-PSCs. It investigates how the carbon ink, usually optimised for maximum sheet conductivity, impacts the infiltration of the perovskite into the active layers, which in turn impacts the performance of the cells. Through the use of secondary electron microscopy with energy-dispersive X-ray spectroscopy, infiltration defects were revealed relating to carbon flake orientation. The cross sections imaged showed between a 2% and 100% inactive area within the C-PSCs due to this carbon blocking effect. The impact of these defects on the performance of solar cells is considerable, and by better understanding these defects devices can be improved for mass manufacture.

Non-invasive electrical brain stimulation for vision restoration after stroke: An exploratory randomized trial (REVIS).

BACKGROUND: Occipital strokes often cause permanent homonymous hemianopia leading to significant disability. In previous studies, non-invasive electrical brain stimulation (NIBS) has improved vision after optic nerve damage and in combination with training after stroke. OBJECTIVE: We explored different NIBS modalities for rehabilitation of hemianopia after chronic stroke. METHODS: In a randomized, double-blinded, sham-controlled, three-armed trial, altogether 56 patients with homonymous hemianopia were recruited. The three experiments were: i) repetitive transorbital alternating current stimulation (rtACS, n = 8) vs. rtACS with prior cathodal transcranial direct current stimulation over the intact visual cortex (tDCS/rtACS, n = 8) vs. sham (n = 8); ii) rtACS (n = 9) vs. sham (n = 9); and iii) tDCS of the visual cortex (n = 7) vs. sham (n = 7). Visual functions were evaluated before and after the intervention, and after eight weeks follow-up. The primary outcome was change in visual field assessed by high-resolution and standard perimetries. The individual modalities were compared within each experimental arm. RESULTS: Primary outcomes in Experiments 1 and 2 were negative. Only significant between-group change was observed in Experiment 3, where tDCS increased visual field of the contralesional eye compared to sham. tDCS/rtACS improved dynamic vision, reading, and visual field of the contralesional eye, but was not superior to other groups. rtACS alone increased foveal sensitivity, but was otherwise ineffective. All trial-related procedures were tolerated well. CONCLUSIONS: This exploratory trial showed safety but no main effect of NIBS on vision restoration after stroke. However, tDCS and combined tDCS/rtACS induced improvements in visually guided performance that need to be confirmed in larger-sample trials.NCT01418820 (clinicaltrials.gov).

Laser-Scribing Optimization for Sprayed SnO2-Based Perovskite Solar Modules on Flexible Plastic Substrates.

Flexible perovskite solar cells (FPSCs) are prime candidates for applications requiring a highly efficient, low-cost, lightweight, thin, and even foldable power source. Despite record efficiencies of lab-scale flexible devices (19.5% on a 0.1 cm2 area), scalability represents a critical factor toward commercialization of FPSCs. Large-area automized deposition techniques and efficient laser scribing procedures are required to enable a high-throughput production of flexible perovskite modules (FPSMs), with the latter being much more challenging compared to glass substrates. In this work, we introduce the combined concept of laser scribing optimization and automatized spray-coating of SnO2 layers. Based on a systematic variation of the incident laser power and a comprehensive morphological and electrical analysis of laser-based cell interconnections, optimal scribing parameters are identified. Furthermore, spray-coating is used to deposit uniform compact SnO2 films on large-area (>120 cm2) plastic substrates. FPSCs with spray-coated SnO2 show comparable performance as spin-coated cells, delivering up to 15.3% efficiency on small areas under 1 sun illumination. When upscaling to large areas, FPSMs deliver 12% power conversion efficiency (PCE) and negligible hysteresis on 16.8 cm2 and 11.7% PCE on a 21.8 cm2 active area. Our perovskite devices preserved 78% efficiency when the active area increased from 0.1 to 16.8 cm2, demonstrating that our combined approach is an effective strategy for large-area manufacturing of perovskite devices on flexible substrates.

Perovskite Photovoltaic Modules: Life Cycle Assessment of Pre-industrial Production Process.

Photovoltaic devices based on perovskite materials have a great potential to become an exceptional source of energy while preserving the environment. However, to enter the global market, they require further development to achieve the necessary performance requirements. The environmental performance of a pre-industrial process of production of a large-area carbon stack perovskite module is analyzed in this work through life cycle assessment (LCA). From the pre-industrial process an ideal process is simulated to establish a benchmark for pre-industrial and laboratory-scale processes. Perovskite is shown to be the most harmful layer of the carbon stack module because of the energy consumed in the preparation and annealing of the precursor solution, and not because of its Pb content. This work stresses the necessity of decreasing energy consumption during module preparation as the most effective way to reduce environmental impacts of perovskite solar cells.

Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke.

Occipital stroke often leads to visual field loss, for which no effective treatment exists. Little is known about the potential of non-invasive electric current stimulation to ameliorate visual functions in patients suffering from unilateral occipital stroke. One reason is the traditional thinking that visual field loss after brain lesions is permanent. Since evidence is available documenting vision restoration by means of vision training or non-invasive electric current stimulation future studies should also consider investigating recovery processes after visual cortical strokes. Here, protocols of repetitive transorbital alternating current stimulation (rtACS) and transcranial direct current stimulation (tDCS) are presented and the European consortium for restoration of vision (REVIS) is introduced. Within the consortium different stimulation approaches will be applied to patients with unilateral occipital strokes resulting in homonymous hemianopic visual field defects. The aim of the study is to evaluate effects of current stimulation of the brain on vision parameters, vision-related quality of life, and physiological parameters that allow concluding about the mechanisms of vision restoration. These include EEG-spectra and coherence measures, and visual evoked potentials. The design of stimulation protocols involves an appropriate sham-stimulation condition and sufficient follow-up periods to test whether the effects are stable. This is the first application of non-invasive current stimulation for vision rehabilitation in stroke-related visual field deficits. Positive results of the trials could have far-reaching implications for clinical practice. The ability of non-invasive electrical current brain stimulation to modulate the activity of neuronal networks may have implications for stroke rehabilitation also in the visual domain.

Rehabilitative approach in patients with ring scotoma.

OBJECTIVE: To investigate the rehabilitative approach in patients with ring scotoma. A central scotoma is characteristic for patients with age-related macular degeneration (AMD). Sometimes patients with AMD maintain a residual central vision area within the scotoma (ring scotoma). DESIGN: Prospective, nonrandomized case series. PARTICIPANTS: Twenty-four patients with AMD. METHODS: A formal low-vision assessment was performed for all study patients. The assessment included best corrected visual acuity (BCVA), contrast sensitivity, reading speed, and microperimetry. All patients were provided a low-vision assessment to satisfy patients' needs. Devices were prescribed accordingly. RESULTS: The BCVA found was 0.4 logMAR (SD 0.1). All had central and stable fixation. Residual central retinal area size and sensitivity measured 2.4° (SD 0.8) and 3.1 dB (SD 0.8), respectively. Twenty patients achieved better vision with optical magnification in the eye with ring scotoma. Mean reading speed achieved was 50.2 words/min (SD 20.9). A linear correlation was found for reading speed with both central area sensitivity (r² = 0.5, p < 0.05) and contrast sensitivity (r² = 0.3, p < 0.05). CONCLUSIONS: In patients with AMD with ring scotoma, moderate amounts of magnification seem to provide satisfactory rehabilitation outcomes. Central retinal spared area sensitivity may predict reading speed outcomes, whereas residual central area size is likely to be useful in determining magnification.