Two-dimensional hybrid perovskites are used as absorbers in solar cells. Our first-generation devices containing (PEA)2(MA)2[Pb3I10] (1; PEA=C6H5(CH2)2NH3+, MA=CH3NH3+) show an open-circuit voltage of 1.18 V and a power conversion efficiency of 4.73 %. The layered structure allows for high-quality films to be deposited through spin coating and high-temperature annealing is not required for device fabrication. The 3D perovskite (MA)[PbI3] (2) has recently been identified as a promising absorber for solar cells. However, its instability to moisture requires anhydrous processing and operating conditions. Films of 1 are more moisture resistant than films of 2 and devices containing 1 can be fabricated under ambient humidity levels. The larger bandgap of the 2D structure is also suitable as the higher bandgap absorber in a dual-absorber tandem device. Compared to 2, the layered perovskite structure may offer greater tunability at the molecular level for material optimization.

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A Layered Hybrid Perovskite Solar-Cell Absorber with Enhanced Moisture Stability

Global environmental concerns and the escalating demand for energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Solar energy is the most abundant, inexhaustible and clean of all the renewable energy resources till date. The power from sun intercepted by the earth is about 1.8 × 1011 MW, which is many times larger than the present rate of all the energy consumption. Photovoltaic technology is one of the finest ways to harness the solar power. This paper reviews the photovoltaic technology, its power generating capability, the different existing light absorbing materials used, its environmental aspect coupled with a variety of its applications. The different existing performance and reliability evaluation models, sizing and control, grid connection and distribution have also been discussed. © 2011 Published by Elsevier Ltd.

A review of solar photovoltaic technologies

The current status of the use of nanoparticles for photothermal treatments is reviewed in detail. The different families of heating nanoparticles are described paying special attention to the physical mechanisms at the root of the light-to-heat conversion processes. The heating efficiencies and spectral working ranges are listed and compared. The most important results obtained in both in vivo and in vitro nanoparticle assisted photothermal treatments are summarized. The advantages and disadvantages of the different heating nanoparticles are discussed.

Nanoparticles for photothermal therapies.

Ligand-stabilized copper selenide (Cu2-xSe) nanocrystals, approximately 16 nm in diameter, were synthesized by a colloidal hot injection method and coated with amphiphilic polymer. The nanocrystals readily disperse in water and exhibit strong near-infrared (NIR) optical absorption with a high molar extinction coefficient of 7.7 × 107 cm–1 M–1 at 980 nm. When excited with 800 nm light, the Cu2-xSe nanocrystals produce significant photothermal heating with a photothermal transduction efficiency of 22%, comparable to nanorods and nanoshells of gold (Au). In vitro photothermal heating of Cu2-xSe nanocrystals in the presence of human colorectal cancer cell (HCT-116) led to cell destruction after 5 min of laser irradiation at 33 W/cm2, demonstrating the viabilitiy of Cu2-xSe nanocrystals for photothermal therapy applications.

Copper selenide nanocrystals for photothermal therapy.

The long-standing popularity of thermoelectric materials has contributed to the creation of various thermoelectric devices and stimulated the development of strategies to improve their thermoelectric performance. In this review, we aim to comprehensively summarize the state-of-the-art strategies for the realization of high-performance thermoelectric materials and devices by establishing the links between synthesis, structural characteristics, properties, underlying chemistry and physics, including structural design (point defects, dislocations, interfaces, inclusions, and pores), multidimensional design (quantum dots/wires, nanoparticles, nanowires, nano- or microbelts, few-layered nanosheets, nano- or microplates, thin films, single crystals, and polycrystalline bulks), and advanced device design (thermoelectric modules, miniature generators and coolers, and flexible thermoelectric generators). The outline of each strategy starts with a concise presentation of their fundamentals and carefully selected examples. In the end, we point out the controversies, challenges, and outlooks toward the future development of thermoelectric materials and devices. Overall, this review will serve to help materials scientists, chemists, and physicists, particularly students and young researchers, in selecting suitable strategies for the improvement of thermoelectrics and potentially other relevant energy conversion technologies.

Advanced Thermoelectric Design: From Materials and Structures to Devices

Antimony sulfide selenide prototype photovoltaic modules surpassing 4% conversion efficiency under the sun – A technological outlook

Structural and opto-electronic properties of chemically deposited CuxS thin film and the precipitate

A thin film of indium approximately 10 nm thick was deposited by thermal evaporation onto a chemically deposited ZnSe thin film of thickness  Annealing the ZnSe-In films in air at 250 to for 15 min resulted in the formation of a -O heterostructure The layer was approximately 10 nm thick with an average grain diameter of 20 nm A sheet resistance of was observed over the film surface which is attributed to a non-stoichiometric film formed on the surface, with an n-type conductivity of  Annealing at or for a longer duration at could reduce this conductivity through improvement in the stoichiometry The optical transmittance of the film for the visible and near-infrared region was  The underlying ZnSe film showed a direct bandgap of 27-275 eV Etching in a dilute HCl solution removed the film and revealed a near-intrinsic ZnSe film, showing electrical properties similar to those of the ZnSe films annealed at the same temperature, with sheet resistance  Applications of the heterostructure to the fabrication of photonic devices are suggested

Formation of a ZnSe:? heterostructure by air annealing ZnSe-In thin film

Chemically deposited PbS, CuxS and PbS-CuxS thin films possess a range of solar control characteristics suitable for architectural window glazing applications in locations with a generally warm climate or subjected to extreme climates. The possibilities of producing large area coatings with very low capital investment is an inherent attraction of chemical bath deposition technique. This aspect makes the chemically deposited metal chalcogenide films as a low-capital alternative to the commercially available magnetron sputtered metallic coatings in the production of solar control glazings.

M. T. S. Nair

Papers

Antimony sulfide selenide prototype photovoltaic modules surpassing 4% conversion efficiency under the sun – A technological outlook

Structural and opto-electronic properties of chemically deposited CuxS thin film and the precipitate

Formation of a ZnSe:? heterostructure by air annealing ZnSe-In thin film

Critical Analysis Of The Solar Control Performance Of Chemically Deposited Metal Chalcogenide Thin Films

Thin film Sn2S3 via chemical deposition and controlled heating – Its prospects as a solar cell absorber