Systematic screening of Retinopathy in Diabetes (REaD project): An Italian implementation campaign

Purpose: To evaluate the use of telemedicine retinal screening in Italy and to identify potential elements of implementation of this system. Methods: Patients with either new-onset diabetes or no ophthalmologic visit over the previous 2 years and attending 33 referral diabetic centers between mid-April 2013 and mid December 2015 were screened. Two partially overlapping nonstereoscopic 45\ub0 digital color images were captured from each eye using a fully automated nonmydriatic digital fundus camera. Factors limiting the assessment of retinopathy were explored. Results: Out of 24,473 eligible individuals, 22,466 had complete data. Among them, good-quality images enabling appropriate evaluation of at least one eye were obtained from 19,712 patients (both eyes, n = 18,887). Although nonmydriatic retinographs were provided, 39% of patients were evaluated using mydriasis. The rate of low-quality images in each center was inversely associated with the number of patients assessed. This was more evident for screening in mydriasis: adjusted odds ratio (OR) 0.79 (95% confidence interval (CI) 0.76-0.82) (p<0.001) vs 0.96 (95% CI 0.94-0.97) (p<0.001). Finally, both the number of patients assessed and use of mydriasis were inversely related to the presence of diabetic retinopathy (DR): adjusted OR 0.93 (95% CI 0.92-0.93) (p<0.001) and 0.88 (95% CI 0.82-0.96) (p<0.001), respectively. Conclusions: This program confirmed a role for teleophthalmology in the systematic screening of DR and provided important suggestions to improve the system deployed. A high level of training is required for operators to optimize imaging. The role of mydriasis should be evaluated furthe

Comparison between a-SiOx:H and a-Si:H as Passivation Buffer Layer for Heterojunction Solar Cells

In crystalline silicon based heterojunction solar cells the surface passivation quality is fundamental to obtain high efficiency. Intrinsic a-Si:H, as obtained by PECVD process from silane dissociation, is a good candidate for surface passivation, but UV absorption of this material limits the current generation. Moreover, surface passivation quality can be compromised when fabrication steps, following the a-Si:H deposition, exceed the a-Si:H deposition temperature. Both drawbacks can be overcome introducing a source of oxygen in PECVD process, obtaining a-SiOx:H layer that provides at the same time high quality passivation, wider optical bandgap and less susceptible to temperature steps than a-Si:H. In this work we compared two heterojunction solar cells different only for front side passivation layer, consisting of a-Si:H or a-SiOx:H. We monitored lifetime and implied Voc during fabrication steps and evaluated the final I-V characteristics and quantum efficiency. We found that the UV light soaking together with heating during subsequent sputtering process, increased lifetime of cell with a-SiOx:H more than that with a-Si:H. Likewise the cell having a-SiOx:H as passivation layer showed electrical parameters higher than the a-Si:H counterpart. Indeed Jsc and Voc were 1mA/cm2 and 20mV respectively higher in cell with a-SiOx:H than in cell with a-Si:H. In particular cell with a-SiOx:H layer achieved an encouraging implied Voc of 751mV

Optimal thermal annealing of a-SiOx layer obtained by pecvd for Heterojunction solar cell application

In a-Si:H/c-Si heterojunction solar cells the UV absorption of amorphous layers limits the current generation. The use of a more transparent material like a-SiOx:H films is a key to further enhance the efficiency of this kind of cells. At the same time this layer must guarantee high surface passivation of the c-Si wafer to be suitable in high efficiency solar cell manufacturing. As for amorphous silicon, thermal annealing procedures are considered as valuable steps to enhance and stabilize thin film properties, when performed at opportune temperature. In order to avoid damages of the amorphous layer, each cell fabrication step should be carried at temperature lower than the emitter formation one. However, when thermal annealing is applied as one of the early fabrication step, the temperature can be high enough to obtain the best passivation properties. In this work we have analyzed the effect of several thermal treatments different for temperature, duration and surrounding atmosphere on a-SiOx:H/c-Si/a-SiOx:H structure. We have fully characterized the samples with the aid of effective lifetime evaluation and FTIR spectra to correlate the effect of thermal annealing to the a-SiOx:H/c-Si interface

Metastability of a-SiOx:H thin films for c-Si surface passivation

The adoption of a-SiOx:H films obtained by PECVD in heterojunction solar cells is a key to further increase efficiency, because of its transparency in the UV with respect to the commonly used a-Si:H. On the other hand the application of amorphous materials like a-Si:H and SiNx on the cell frontside expose them to the mostly energetic part of the sun spectrum, leading to a metastability of their passivation properties. In this work we explore the reliability of a-SiOx:H thin film layers surface passivation on c-Si substrates under UV exposition, in combination with thermal annealing steps. Both p-and n-type doped c-Si substrates have been considered. To understand the effect of UV light soaking we monitored the minority carriers lifetime and Si-H and Si-O bonding, by FTIR spectra, after different exposure times to light coming from a deuterium lamp, filtered to UV-A region, and focused on the sample to obtain a power density of 500 uW/cm2. We found a certain lifetime decrease after UV light soaking in both p- and n-type c-Si passivated wafers. The role of a thermal annealing, which usually enhances the as-deposited SiOx passivation properties, is furthermore considered. In particular we monitored the UV light soaking effect on c-Si wafers after SiOx coating by PECVD and after a thermal annealing treatment at 250°C for 15'. We found that after UV exposure thermal annealing steps can be used as a tool for the c-Si passivation recovery

From a-Si:H to a-SiOx:H: the role of CO2 and H2 in PECVD deposition process

Recently a-SiOx:H has attracted interest in heterojunction solar cells fabrication, because of its effective crystalline silicon surface passivation and larger optical bandgap than a-Si:H. Both amorphous layers are commonly deposited by PECVD from silane dissociation in hydrogen dilution. to obtain a-SiOx:H film, CO2 as source of oxygen is added to gas mixture, that heavily modifies the film growth, the composition and hydrogen inclusion, which influence the passivation properties. In this work we have analyzed the role of CO2 and H2 in the film growth and composition. In particular we have compared the effect of the two kind of amorphous layers on the effective lifetime of c-Si wafers, monitoring the lifetime stability and the effect of thermal treatment. FTIR analysis has been used to correlate the passivation properties to chemical bonding among silicon, hydrogen and oxygen. We have found that H2 dilution in the gas mixture during the film growth is the key to obtain high effective lifetime on c-Si wafers passivated with both kind of amorphous films. On samples coated with a-Si:H or a-SiOx:H different metastability has been observed on as-deposited, thermally annealed and TCO covered films. In particular the effective lifetime can improve up to 200% after thermal annealing being almost stable. Finally we have compared heterojunction solar cells with a-Si:H and a-SiOx:H buffer to remark different performances in Jsc and Voc due to film transparency and passivation capability

Ranibizumab for Visual Impairment due to Diabetic Macular Edema: Real-World Evidence in the Italian Population (PRIDE Study)

Purpose. An expanded access program (PRIDE study) in Italy to provide ranibizumab 0.5 mg to diabetic macular edema (DME) patients, prior to reimbursement. Methods. Open-label, prospective, phase IIIb study. Majority of patients were not treatment-naïve before enrollment. Patients received ranibizumab as per the EU label (2011). Safety was assessed by incidences of ocular/systemic adverse events (AEs) and serious AEs (SAEs) and efficacy in terms of visual acuity (VA) change from baseline (decimal score or Snellen (20/value)). Results. Overall, 515 patients (83.5%) completed the study. In unilateral/bilateral patients, commonly observed AEs were cardiac disorders (1.3%/1.3%) and nervous system disorders (1.3%/1.1%); SAEs were reported in 4.5%/4.8% of patients. Acute renal failure, lung carcinoma, and cardiac arrest were the causes of death in one unilateral and two bilateral patients. Ranibizumab improved/maintained VA (Snellen (20/value)/decimal scores) in both unilateral (up to −16.7/1.5) and bilateral patients (up to −23.6/1.2) at Month 5, with a mean of 4.15 and 4.40 injections, respectively. Overall, no difference was observed in the VA outcomes and treatment exposure between unilateral/bilateral patients. Conclusions. The PRIDE study provided early ranibizumab access to >600 Italian patients. Ranibizumab was well-tolerated and improved/maintained VA in 40.2%–68.8% patients, with no differences in case of unilateral or bilateral pathology. The study is registered with EudraCT

Hydrogenated silicon sub-oxide film for an effective and thermal stable silicon surface passivation

Scope of the work is to get a comprehensive study on electrical and optical characteristics of SiOx:H film within the role of CO and H in the film growth and composition and on how the Oxygen additionchanges the film structure and Hydrogen inclusion in the amorphous matrix and their chemical bonding with silicon. We monitored the effective lifetime tEFF and FTIR spectraon as-deposited and thermal treated samples to understand the passivation mechanism,correlating wafer lifetime and Hydrogen inclusion in sub-oxide film. H dilution in the gas mixture was the key to enhances passivation quality on c-Si wafers

Mechanically stacked, two-terminal graphene-based perovskite/silicon tandem solar cell with efficiency over 26%

Perovskite/silicon tandem solar cells represent an attractive pathway to upgrade the market-leading crystalline silicon technology beyond its theoretical limit. Two-terminal architectures result in reduced plant costs compared to four-terminal ones. However, it is challenging to monolithically process perovskite solar cells directly onto the micrometer-sized texturing on the front surface of record-high efficiency amorphous/crystalline silicon heterojunction cells, which limits both high-temperature and solution processing of the top cells. To tackle these hurdles, we present a mechanically stacked two-terminal perovskite/silicon tandem solar cell, with the sub-cells independently fabricated, optimized, and subsequently coupled by contacting the back electrode of the mesoscopic perovskite top cell with the texturized and metalized front contact of the silicon bottom cell. By minimizing optical losses, as achieved by engineering the hole selective layer/rear contact structure, and using a graphene-doped mesoporous electron selective layer for the perovskite top cell, the champion tandem device demonstrates a 26.3% efficiency (25.9% stabilized) over an active area of 1.43 cm2