Burn-in" degradation occurs in many polymer solar cells, which dramatically reduces the overall power output of the cells at the early hundred hours. Understanding the "burn-in" degradation mechanism is therefore highly important to improve the lifetime of the cell. In this article, the decay behaviors of P3HT:PC 61 BM solar cells depending on the molecular weight of P3HT were systematically investigated. Although all of these P3HTs were highly crystalline with regioregularity of 94−97%, the stability of P3HT:PC 61 BM cells showed a nonmonotonic dependence on P3HT molecular weight. The cells based on P3HT with a weight average molecular weight (M w ) of 20 K showed much faster decadence in open circuit voltage (V OC ) and fill factor (FF) during aging, yielding the lowest stability in comparison with that based on P3HT of 10, 25, and 30 K. UV−vis absorption and external quantum efficiency spectra demonstrated that the performance decay is not attributed to the change in the photoactive layer. The recovery of V OC and FF of the aged cells after renewing the MoO 3 /Al electrode revealed that the performance decay is mainly because of the interfacial degradation of P3HT:PC 61 BM/MoO 3 . Electron spin resonance spectroscopy and X-ray photoelectronic spectroscopy confirmed the photon-induced redox reaction between P3HT and MoO 3 under light illumination, where P3HT is oxidized to the polaron and Mo(VI) was partially reduced to Mo(V). The photon chemical reduction (PCR) of MoO 3 by P3HT is then ascribed as the essential reason for the fast V OC and FF decays of the cells during aging. The surface morphology of the photoactive layer measured by the atomic force microscope revealed the much rougher surface of the P3HT-20 K/PC 61 BM film. Such a rough surface increases the contact area between P3HT and MoO 3 , and consequently enhances the PCR of MoO 3 and P3HT, which is considered as the main reason for the molecular weight-dependent degradation behaviors. For the first time, the current work clearly demonstrates that the photoreduction of the metal oxide and photoactive layer would lead to fast V OC and FF decays, which could be a very important degradation pathway for polymer solar cells.

Purpose:Recurrent ureteropelvic junction obstruction (UPJO) after failed pyeloplasty is a complex surgical dilemma. The robot-assisted laparoscopic ureterocalicostomy (RALUC) is a potential surgical approach, but widespread adoption is limited due to the perceived technical challenge of the procedure. We present a multi-institutional pediatric cohort undergoing RALUC for recurrent or complex UPJO, and hypothesize that the procedure is reproducible, safe and efficacious.Materials and Methods:A 3-center multi-institutional collaboration was initiated and medical records of children undergoing RALUC between 2012 and 2020 were retrospectively reviewed. The details on baseline demographics, perioperative characteristics and postoperative outcomes were aggregated.Results:During the study period 24 patients, 7 (29%) females and 17 (71%) males, were identified. Of the patients 21 (86%) had a history of previous pyeloplasty prior to RALUC, of whom 5 (24%) had 2 prior failed ipsilateral pyeloplasties. The reason for performing RALUC was short ureter in 3 (13%), intrarenal pelvis in 5 (21%) and extensive scarring at the ureteropelvic junction locus in 16 (67%) patients. The median age of patients at time of surgery was 5.1 years (IQR: 1.9, 14.7). Of the patients 9 (38%) had percutaneous nephrostomy prior to surgery; if percutaneous nephrostomy tubes were placed for relief of obstruction, an antegrade contrast study was done postoperatively to confirm resolution of obstruction. No 30-day Clavien-Dindo Grade III-V complications were noted. During the median followup of 16.1 months (IQR: 6, 47.5), 22 (92%) had improved symptoms and hydronephrosis with no further intervention; 2 (8%) patients underwent endoscopic interventions after RALUC and both ultimately underwent nephrectomy.Conclusions:This multi-institutional cohort demonstrates that RALUC is a safe and efficacious salvage option for failed pyeloplasty or complex anatomy with an acceptable success profile, especially in cases of extensive scarring at the UPJO or an intrarenal pelvis.

Bulk-heterojunction nanoparticle dispersions in water or alcohol can be employed as eco-friendly inks for the fabrication of organic solar cells by printing or coating. However, one major drawback is the need for stabilizing surfactants, which facilitate nanoparticle formation but later hamper device performance. When surfactant-free dispersions are formulated, a strong limitation is imposed by the dispersion concentration due to the tendency of nanoparticles to aggregate. In this work, pyridine end-capped poly­(3-hexylthiophene) (P3HT-Py) is synthesized and included as an additive for the stabilization of P3HT:indene-C60 bis-adduct (ICBA) nanoparticle dispersions. In the presence of acetic acid (AcOH), a surface-active pyridinium acetate end-capped P3HT ion pair, P3HT-PyH+AcO–, is formed which effectively stabilizes the dispersion and hence allows the formation of dispersions with smaller nanoparticle sizes and higher concentrations of up to 30 mg/mL in methanol. The dispersions exhibit an enhanced shelf-lifetime of at least 60 days at room temperature. After the deposition of light-harvesting layers from the nanoparticle dispersions, the ion-pair formation is reversed at elevated temperatures leading to regeneration of P3HT-Py and AcOH. The AcOH evaporates from the active layer, while the performance of the corresponding solar cells is not affected by the residual P3HT-Py in the devices. Enhanced nanoparticle stability is achieved with only 0.017 wt % pyridine in the P3HT/ICBA formulation.

ultrasound showed a decompressed, but still hydronephrotic, left kidney.CONCLUSIONS: This video demonstrates that a roboticassisted laparoscopic pyeloplasty with the use of a CPU stent can safely and effectively be performed in infants, even with duplicated systems. The CPU stent allows for stent removal in the office, avoiding a second round of anesthesia for the patient.

Daily life is surrounded by the use of optoelectronics in order to provide illumination for the most basic of routines.For this reason, research into the performance enhancement of such optoelectronic devices is paramount in order to understand methods of improving efficiency and thus conserving energy and resources. This review briefly summarized various techniques to fabricate nanopillars for enhancing performance of light emitting diode (LED), using etching masks, nanosphere lithography, integration of other materials, and MOVPE manipulation.