Monolithic Two-Terminal Perovskite/CIS Tandem Solar Cells with Efficiency Approaching 25

Monolithic two-terminal (2T) perovskite/CuInSe₂ (CIS) tandem solar cells (TSCs) combine the promise of an efficient tandem photovoltaic (PV) technology with the simplicity of an all-thin-film device architecture that is compatible with flexible and lightweight PV. In this work, we present the first-ever 2T perovskite/CIS TSC with a power conversion efficiency (PCE) approaching 25% (23.5% certified, area 0.5 cm²). The relatively planar surface profile and narrow band gap (∼1.03 eV) of our CIS bottom cell allow us to exploit the optoelectronic properties and photostability of a low-Br-containing perovskite top cell as revealed by advanced characterization techniques. Current matching was attained by proper tuning of the thickness and bandgap of the perovskite, along with the optimization of an antireflective coating for improved light in-coupling. Our study sets the baseline for fabricating efficient perovskite/CIS TSCs, paving the way for future developments that might push the efficiencies to over 30%.

Harvesting Sub-bandgap Photons via Upconversion for Perovskite Solar Cells

Lanthanide-based upconversion (UC) allows harvesting sub-bandgap near-infrared photons in photovoltaics. In this work, we investigate UC in perovskite solar cells by implementing UC single crystal BaF₂:Yb³⁺, Er³⁺ at the rear of the solar cell. Upon illumination with high-intensity sub-bandgap photons at 980 nm, the BaF₂:Yb³⁺, Er³⁺ crystal emits upconverted photons in the spectral range between 520 and 700 nm. When tested under terrestrial sunlight representing one sun above the perovskite's bandgap and sub-bandgap illumination at 980 nm, upconverted photons contribute a 0.38 mA/cm² enhancement in the short-circuit current density at lower intensity. The current enhancement scales non-linearly with the incident intensity of sub-bandgap illumination, and at higher intensity, 2.09 mA/cm² enhancement in current was observed. Hence, our study shows that using a fluoride single crystal like BaF₂:Yb³⁺, Er³⁺ for UC is a suitable method to extend the response of perovskite solar cells to near-infrared illumination at 980 nm with a subsequent enhancement in current for very high incident intensity.

Impact of n-Butylammonium Bromide on the Chemical and Electronic Structure of Double-Cation Perovskite Thin Films

2D/3D perovskite heterostructures have emerged as a promising material composition to reduce nonradiative recombination in perovskite-based LEDs and solar cells. Such heterostructures can be created by a surface treatment with large organic cations, for example, n-butylammonium bromide (BABr). To understand the impact of the BABr surface treatment on the double-cation (Cs0.17FA0.83Pb(I0.6Br0.4)3) (FA = formamidinium) perovskite thin film and further optimize the corresponding structures, an in-depth understanding of the chemical and electronic properties of the involved surfaces, interfaces, and bulk is required. Hence, we study the impact of the BABr treatment with a combination of surface-sensitive X-ray photoelectron spectroscopy and bulk-sensitive resonant inelastic soft X-ray scattering (RIXS). A quantitative analysis of the BABr-treated perovskite thin film shows a modified chemical perovskite surface environment of carbon, nitrogen, bromine, iodine, and lead, indicating that the treatment leads to a perovskite surface with a modified composition and bonding structure. With K-edge RIXS, the local environment at the nitrogen and carbon atoms is probed, allowing us to identify the presence of BABr in the perovskite bulk albeit with a modified bonding environment. This, in turn, identifies a "hidden parameter" for the optimization of the BABr treatment and overall performance of 2D/3D perovskite solar cell absorbers.

Picosecond Capture of Photoexcited Electrons Improves Photovoltaic Conversion in MAPbI3 :C70 -Doped Planar and Mesoporous Solar Cells

In this work, solar cells based on methylammonium lead iodide (MAPbI3 ) doped in solution with C70 fullerene in a mesoporous as well as planar electron-transporting layer (ETL)-free architecture are realized, showcasing in the latter case a record efficiency of 15.7% and an improved open-circuit voltage (VOC ). Contrary to the bulk heterojunction previously reported, the C70 molecules do not phase segregate and they are rather finely dispersed in the perovskite film, possibly infiltrating at the grain boundaries, while assisting the growth of a highly uniform perovskite layer. By means of time-resolved femtosecond-to-nanosecond optical spectroscopy, with an extended spectral coverage, it is observed that electrons photogenerated in the perovskite are transferred to C70 with a time constant of 20 ps. Despite being captured by C70 , electrons are not deeply trapped and can potentially bounce back into the perovskite, as suggested by the high fill factor and enhanced VOC of the MAPbI3 :C70 solar cells, especially in the case of the ETL-free device configuration.

Temperature Variation-Induced Performance Decline of Perovskite Solar Cells

This paper reports on the impact of outdoor temperature variations on the performance of organo metal halide perovskite solar cells (PSCs). It shows that the open-circuit voltage ( V_OC) of a PSC decreases linearly with increasing temperature. Interestingly, in contrast to these expected trends, the current density ( J_SC) of PSCs is found to decline strongly below 20% of the initial value upon cycling the temperatures from 10 to 60 °C and back. This decline in the current density is driven by an increasing series resistance and is caused by the fast temperature variations as it is not apparent for solar cells exposed to constant temperatures of the same range. The effect is fully reversible when the devices are kept illuminated at an open circuit for several hours. Given these observations, an explanation that ascribes the temperature variation-induced performance decline to ion accumulation at the contacts of the solar cell because of temperature variation-induced changes of the built-in field of the PSC is proposed. The effect might be a major obstacle for perovskite photovoltaics because the devices exposed to real outdoor temperature profiles over 4 h showed a performance decline of >15% when operated at a maximum power point.

EGFR rs11506105 and IFNL3 SNPs but not rs8099917 are strongly associated with treatment responses in Iranian patients with chronic hepatitis C

Interferon lambda 3 (IFNL3) and epidermal growth factor receptor (EGFR) single nucleotide polymorphisms (SNPs) may play a key role in the spontaneous clearance of hepatitis C virus (HCV) and treatment responses. The aim of this study was to evaluate the effect of IFNL3 SNPs and EGFR rs11506105 on treatment outcomes in patients with chronic HCV (CHC). IFNL3 SNPs and EGFR rs11506105 were genotyped by PCR-restriction fragment length polymorphism and PCR-sequencing, respectively, in 235 naïve patients with CHC infection. The frequency of rapid virologic response (RVR), complete early virologic response (cEVR) and sustained virologic response (SVR) were 52.3%, 76.2% and 64.7% respectively. The results of this study showed that RVR was associated with ALT (P=0.015), AST (P=0.020), IFNL3 rs12979860 (CC) (P=0.043), rs12980275 (AA) (P=1 × 10-4), and EGFR rs11506105 (AA) (P=0.010), and IFNL3 rs12979860 (CC) (P=0.048), rs12980275 (AA) (P=0.022), and EGFR rs11506105 (AA) (P=0.006) were correlated with cEVR. HCV genotype (P=0.007), IFNL3 rs12979860 (CC) (P=0.023), IFNL3 rs12980275 (AA) (P=1 × 10-4), EGFR rs11506105 (AA) (P=0.005), RVR (P=1 × 10-4), and cEVR (P=0.003) were significant predictors for SVR. These results, for the first time, revealed that beside IFNL3 SNPs, EGFR rs11506105 is strongly associated with RVR, cEVR and SVR. EGFR rs11506105 besides IFNL3 SNPs could predict treatment responses in CHC patients.

Inherent inferior quality of follicular fluid in repeat breeder heifers as evidenced by low rates of in vitro production of bovine embryos

The aims of the present study were to determine the effect of follicular fluid obtained from the ovulatory follicle of repeat breeder heifers on in vitro oocyte maturation (Experiment 1), fertilization (Experiment 2) and production of bovine embryos (Experiment 3). Holstein virgin heifers (VH, n = 5) with normal fertility or repeat breeder syndrome (RBH, n = 5) were used in the present study. Follicular fluid of VH and RBH was aspirated from ovulatory follicles and used as maturation medium. Bovine oocytes were aspirated from follicles of slaughterhouse ovaries and randomly allocated in three groups; in Group 1, oocytes cultured in TCM-199 supplemented with 10% heat-treated fetal calf serum and hormones (5 IU/mL hCG plus 0.1 IU/mL rFSH); in Group 2, oocytes cultured in TCM-199 supplemented with 10% filtered follicular fluid of VH without hormones; in Group 3, oocytes cultured in TCM-199 supplemented with 10% filtered follicular fluid of RBH without hormones. The mean (±SEM) percentage of matured oocytes was different between VH and RBH groups (72.2 ± 4.0 vs 56.4 ± 4.6%; P < 0.05, respectively). Further, the mean (±SEM) percentage of normal oocyte fertilization was higher in the VH than the RBH group (49.3 ± 2.1 vs 32.0 ± 4.2; P < 0.05, respectively). The mean percentage of embryos developed to the blastocyst stage was higher in the VH than the RBH group (12.0 ± 1.3 vs 7.0 ± 1.6; respectively; P < 0.05). In conclusion, our findings support our hypothesis that the ovulatory follicle microenvironment of Holstein repeat breeder heifers places their oocytes at a developmental disadvantage compared with Holstein fertile virgin heifers and that this suggest the existence of an inherent inferior quality of the ovulatory follicle microenvironment in repeat breeding Holstein heifers.

All-inorganic large-area low-cost and durable flexible perovskite solar cells using copper foil as a substrate

All-inorganic large-area, low-cost, and durable flexible perovskite solar cells using copper foil as a substrate are introduced.

Influence of Perovskite Morphology on Slow and Fast Charge Transport and Hysteresis in the Perovskite Solar Cells

We have investigated the influence of perovskite morphology on slow and fast charge transport in the perovskite solar cells. Solar cells with different perovskite cuboid sizes (50-300 nm) have been fabricated using various methylammonium iodide concentrations. Both the low-frequency capacitance and hysteresis are maximum for the cell with the largest perovskite grains (300 nm). The low-frequency capacitance is about three orders of magnitude greater than the intermediate frequency capacitance, indicating the great role of ions on the slow responses and hysteresis. The measurement of open-circuit voltage decay indicates that for the large grains of 300 nm up to 70% of V_oc remains across the cell, even after passing ∼40 s. Such a long time V_oc decay demonstrates the large accumulation of the ions at the perovskite interfaces with electron and hole transport layers, which conduct slow redistribution of the charges after the light is turned off.

Two-Step Physical Deposition of a Compact CuI Hole-Transport Layer and the Formation of an Interfacial Species in Perovskite Solar Cells

A simple and practical approach is introduced for the deposition of CuI as an inexpensive inorganic hole-transport material (HTM) for the fabrication of low cost perovskite solar cells (PSCs) by gas-solid phase transformation of Cu to CuI. The method provides a uniform and well-controlled CuI layer with large grains and good compactness that prevents the direct connection between the contact electrodes. Solar cells prepared with CuI as the HTM with Au electrodes displays an exceptionally high short-circuit current density of 32 mA cm(-2) , owing to an interfacial species formed between the perovskite and the Cu resulting in a long wavelength contribution to the incident photon-to-electron conversion efficiency (IPCE), and an overall power conversion efficiency (PCE) of 7.4 %. The growth of crystalline and uniform CuI on a low roughness perovskite layer leads to remarkably high charge extraction in the cells, which originates from the high hole mobility of CuI in addition to a large number of contact points between CuI and the perovskite layer. In addition, the solvent-free method has no damaging side effect on the perovskite layer, which makes it an appropriate method for large scale applications of CuI in perovskite solar cells.

The Association Between Blood Pressure and Normal Range Thyroid Function Tests in a Population Based Tehran Thyroid Study

Several studies have shown an association between overt hypothyroidism and diastolic hypertension. Association between subclinical hypothyroidism and hypertension is a matter of debate. The aim of this study was to examine the association of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure with serum thyroid hormones levels in euthyroid subjects.Data from 4 756 individuals of the Tehran Thyroid study (TTS) without any previously known thyroid disease were analyzed. We divided participants based on TSH tertiles. Serum TSH and free T4 (FT4) concentration, systolic blood pressure (SBP), diastolic blood pressure (BPD) body mass index (BMI) were measured in all subjects.Among 5 786 individuals participated, 4 985 were euthyroid. After implementing exclusion criteria, 4 756 individuals remained of whom 2 122 (44.6%) were male and 2 634 (55.4%) were female. Multiple linear regression analysis revealed no association between TSH levels within reference ranges and blood pressure profile. No significant relationship was observed between TSH levels and systolic or diastolic blood pressure or the mean arterial pressure or pulse pressure in each tertile of TSH. There was a negative association between pulse pressure and TSH in the second tertile (r=- 0.066, p=0.009). Regression analysis showed that FT4 was significantly associated with systolic blood pressure, diastolic blood pressure, pulse pressure and mean arterial pressure.No association was found between serum TSH and blood pressure profile in euthyroid subjects. Serum FT4 levels showed a positive association with blood pressure profiles.

Cuprous Oxide as a Potential Low-Cost Hole-Transport Material for Stable Perovskite Solar Cells

Inorganic hole-transport materials are commercially desired to decrease the fabrication cost of perovskite solar cells. Here, Cu2O is introduced as a potential hole-transport material for stable, low-cost devices. Considering that Cu2O formation is highly sensitive to the underlying mixture of perovskite precursors and their solvents, we proposed and engineered a technique for reactive magnetron sputtering. The rotational angular deposition of Cu2O yields high surface coverage of the perovskite layer for high rate of charge extraction. Deposition of this Cu2O layer on the pinhole-free perovskite layer produces devices with power conversion efficiency values of up to 8.93%. The engineered Cu2O layers showed uniform, compact, and crack-free surfaces on the perovskite layer without affecting the perovskite structure, which is desired for deposition of the top metal contact and for surface shielding against moisture and mechanical damages.

Potential continuous removal of toluene by ZnO nanorods grown on permeable alumina tube filters

Vertical ZnO nanorods were successfully grown on the crystalline surface of an Al₂O₃ microfilter by the simple technique of evaporation of prepared solution at atmospheric pressure (ESAP) for photocatalytic degradation of toluene.

Prevalence of hypothyroidism in patients with dyslipidemia: Tehran Thyroid Study (TTS)

Hypothyroidism is a relatively common endocrine disorder usually accompanied with changes in serum lipid profiles. The purpose of this study was to assess the association between dyslipidemia and hypothyroidism in a population-based study. In this cross-sectional study, 2,315 dyslipidemic patients, aged 20-90 years (mean age: 38.1 ± 13.2 years), were selected from among 5,760 participants of Tehran Thyroid Study and divided into 3 groups, the subclinical hypothyroid, overt hypothyroid, and euthyroid subjects, based on national reference ranges. Serum lipid profiles, free thyroxine (FT4), thyroid stimulating hormone (TSH), and thyroid peroxidase antibody (TPOAb) were measured in all subjects. In subjects with dyslipidemia and nondyslipidemia, the prevalence of subclinical was 7% and 4.1%, respectively, and for clinical hypothyroidism 3% and 1.2%, respectively. In dyslipidemic subjects, the mean low density lipoprotein-cholesterol (LDL-C) levels differed significantly (p = 0.03) among the overt hypothyroid (144.3 ± 36.1), subclinical hypothyroid (129.3 ± 39.2), and euthyroid (132.7 ± 39.0) groups. In the overt hypothyroid group, mean total cholesterol level was higher than in the normal group, but not significant. There were no differences in median triglycerides (TG) and mean high density lipoprotein-cholesterol (HDL-C) levels among the 3 groups mentioned. After adjusting for age and sex, hypothyroidism was not related to elevated serum lipid profiles in patient with dyslipidemia. In conclusion, there is significant difference in the prevalence of subclinical and clinical hypothyroidism between nondyslipidemic and dyslipidemic subjects; after adjustment for age and sex the presence of dyslipidemia did not predict the presence of hypothyroidism.

Underestimation of thyroid dysfunction risk due to regression dilution bias in a long-term follow-up: Tehran Thyroid Study (TTS)

Thyroid dysfunction is linked with mortality and particular diseases. Intra-individual variability of measured thyroid function parameters may bias its association with outcomes, the so called "regression dilution" bias. Single measurements of thyroid function parameters result in underestimation of real associations between outcome rates with the "usual life-long levels" of the aforesaid parameters. The aim of this study was to examine the intra-individual variability of FT4 and TSH of study cohorts in the Tehran Thyroid Study (TTS) and to investigate the extent of the risk underestimation during the 4 phases (Ph) of TTS, with median follow-up of 4, 7, and 10 years between the Ph2-Ph1, Ph3-Ph1, and Ph4-Ph1 intervals; respectively. We estimated regression dilution ratios (RDRs) by the Rosner method of linear regression of repeated measures for FT4 and TSH. RDR1, RDR2, and RDR3 were obtained by regressing the repeated measures of the aforesaid parameters of the last 3 TTS follow-ups on the baseline measurements. Calculations showed 0.64 RDR1, 0.58 RDR2, and 0.52 RDR3 for TSH; and 0.62 RDR1, 0.57 RDR2, and 0.55 RDR3 for FT4. A single measurement-based risk estimation in the TTS was underestimated for FT4 about 61.2, 76.5, and 80.4%; and for TSH as 55.8, 73.1 and 93% after 4, 7, and 10 years of follow-up; respectively. In conclusion, using only single measurements of TSH and FT4 the association between thyroid function and outcome rates is considerably underestimated, especially after a long follow-up period.

Temperature and intensity of sonoluminescence radiation in sulfuric acid

The spectral radiation of sonoluminescence (SL) from sulfuric acid doped with various Xe concentrations has been studied in a hydrochemical simulation, including radiation effects of both continuum and line emissions. The simulation considers the same temperature for both continuum and line parts of the SL spectrum and gives results in agreement with the experiment. Also, it can properly show period-doubling dynamics for a 50 torr bubble. For most of the allowable driving pressures, it is shown that both the temperature and the intensity of SL for a 4 torr bubble are greater than those of a 50 torr bubble. However, for the range of pressures near the maximum driving conditions of the 50 torr bubble, the SL intensity of this bubble can be up to three orders of magnitude greater than the 4 torr bubble. This case, which is in agreement with the experiment, is obtained when the light-emitting region of the 50 torr bubble is about three orders of magnitude greater than the 4 torr bubble.