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This work presents the next paradigm shift in solar energy technology in which a novel iodide-based DES-like mixture has been first investigated as an active electrolyte solvent in dye-sensitized solar cells (DSSCs) in the absence of any co-solvent and any external iodide source. The optimization of the cell design jointly with a bespoke dye functionalized with a hydrophobic chain, properly positioned along the molecular backbone, ensures (a) one of the highest power conversion efficiencies (PCEs) up to 4% for DSSCs based on non-VOC solvents, and (b) a remarkable temporal stability of nearly 95% over a period longer than 2 months. Higher power conversion efficiency values (up to 8.0%) than those reported in the literature with traditional sensitizers and environmentally friendly electrolytes (e.g., water-based electrolytes) have been achieved under low-light illumination. These results are very promising for the realization of next-generation nature-inspired low-cost and high-performing DSSC devices for indoor and outdoor applications.

Synthetic hybrid perovskites of general formula APbI3 are taking the stage in the solar energy field for their outstanding optoelectronic properties, solution processability, limited costs of precursors and straightforward synthesis. However, the fabrication of high-quality materials still suffers from reduced outputs, the use of non-benign chemicals and the need for well-controlled conditions, limiting the attractiveness and feasibility for the industry. Our group designed a colloidal approach, carried at room temperature and in laboratory atmosphere, optimizing the procedure for all-inorganic CsPbBr3. The method proved to be reliable on a multigram scale thanks to an industrial dispersing tool and opened to the recycling of waste while providing idoneous nanocrystals for ink formulation. Extension of the protocol to the iodine containing APbI3 phases having applications for outdoor photovoltaic, requires extensive optimization of the method due to different solubility of the precursors as well as the inherent reduced stability of iodine rich phases with respect to CsPbBr3. The two most relevant challenges are the incorporation of methylammonium or formamidinium ions in the place of cesium into the perovskite crystals and the limited solubility of lead(II) iodide in the low boiling point solvents (heptane and 2-PrOH) we previously identified as ideal for the colloidal synthesis approach and recycle. Tuning the concentration of the cation containing precursor solutions as well as carefully controlling the halide stoichiometry are both key to develop viable syntheses. The limited solubility of the Lead(II) precursors is a more challenging issue. On following up with recent literature reports, we identified three strategies: a) replacing PbX2 with salts containing the Pb(II) and the X- species separately and along with spectator counterions; b) introducing complexation agents capable of enhancing the PbI2 solubility in the target solvents and c) operating in excess of

Alternative forms of evaluation can provide deep and powerful learning experiences for students. Explains how to implement portfolios as an evaluation tool and describes a problem that was successfully implemented in a second semester reform calculus class. (Author/ASK)

A revision of a manual first produced in 1980, this guide is designed to help local school districts in Minnesota meet the educational needs of their limited-English-proficient (LEP) students in academically and administratively expedient ways. The chapters in the manual, which correspond to topics pertinent to designing and maintaining an LEP program, may also serve as resources when informing other district personnel and the community about the purposes and goals of the program. Each chapter begins with common questions and answers. Chapters are as follows: (1) legal rights and responsibilities (federal legislation and guidelines, U.S. Supreme Court decisions, Minnesota law); (2) funding sources (local, state, federal); (3) program staff (licensure/hiring, training, pre-professional skills test requirements, use of paraprofessionals, role of LEP teachers in mainstream instruction); (4) entrance/exit procedures (Minnesota's definition of LEP students, identification, student placement, LEP service for foreign students, exit procedures and transition to the mainstream); (5) instructional program (models, materials, additional program services, support staff); (6) assessment and evaluation of LEP students (home language/first language skills, English language tests, standardized tests, assessment for LEP program exit, mainstream classroom tests, competency/benchmark testing, special education assessment/evaluation); (7) factors that affect school success (native language use, mainstream teacher, cultural differences, school orientation, transition stress); and (8) parents and community (home-school communication, conferences/visits, resources, interpreters). Several appendices provide copies of actual state documents, a list of approved licensure programs, a home language questionnaire, parent notification forms, and a list of resources. (LB)

The Suzuki–Miyaura cross-coupling reaction plays a fundamental role in modern synthetic organic chemistry, both in academia and industry. For this reason, scientists continue to search for new, more effective, cheaper and environmentally friendly procedures. Recently, micellar synthetic chemistry has been demonstrated to be an excellent strategy for achieving chemical transformations in a more efficient way, thanks to the creation of nanoreactors in aqueous environments using selected surfactants. In particular, the cheap and commercially available surfactant Kolliphor EL (a polyethoxylated castor oil derivative) has been used with success to achieve metal-catalyzed transformations in water with high yields and short reaction times, with the advantage of using air-sensitive catalysts without the need for inert atmosphere. In this work, the Kolliphor EL methodology was applied to the Suzuki cross-coupling reaction between thiophene and aniline, using the highly effective catalyst Pd(dtbpf)Cl2. The cross-coupling products were achieved at up to 98% yield, with reaction times of up to only 15 min, working at room temperature and without the need for inert atmosphere.

Di-branched dyes based on a triphenylamino (TPA) donor core have been functionalized with different aromatic and heteroaromatic peripheral groups bonded to TPA as auxiliary donors and investigated as sensitizers in DSSC. The different aromatic and heteroaromatic substitution significantly perturbed the optical properties of the dyes compared to the unsubstituted TPA reference dye, in turn leading to enhanced photovoltaic performances in terms of photocurrent, photovoltage, and power conversion efficiency (PCE). The enhancement originated from improved strategic interface interactions between the dye-sensitized titania and the liquid electrolyte, as ascertained by current-voltage, quantum efficiency (IPCE), light harvesting properties (LHE), and impedance spectroscopy (EIS) studies.

The latest trend in solar cell technology is to develop photon managing processes that adapt the solar emission to the spectral range at which the devices show the largest intrinsic efficiency. Triplet-triplet annihilation-assisted photon upconversion (sTTA-UC) is currently the most promising process to blue-shift sub-bandgap photons at solar irradiance, even if the narrow absorption band of the employed chromophores limits its application. In this work, we demonstrate how to obtain broadband sTTA-UC at sub-solar irradiance, by enhancing the system's light-harvesting ability by way of an ad-hoc synthesized family of chromophores with complementary absorption properties. The overall absorptance is boosted, thus doubling the number of upconverted photons and significantly reducing the irradiance required to achieve the maximum upconversion yield. An outstanding yield of ≈10% is obtained under broadband air mass (AM) 1.5 conditions, which allows a DSSC device to operate by exploiting exclusively sub-bandgap photons. Broadband triplet-triplet annihilation-assisted photon upconversion is demonstrated at subsolar irradiance by the simultaneous use of several light harvesters. An unprecedented yield of 10% is obtained under air mass (AM) 1.5 conditions in a fully organic system, which allows a dye-sensitized solar cell device to operate by exploiting exclusively sub-bandgap photons.