Nanostructured Optoelectronics: Materials and Devices

Electronics

Two-dimensional (2D) materials, an electrifying family of innovative materials, have recently attracted wide attention due to their remarkable characteristics, primarily their high optical transparency, exceptional metallic conductivity, high mechanical strength, carrier mobility, tunable band gap values, and optimum work function. Interestingly, 2D-nanosheets/nanolayers (2D-NLs) might be synthesized into single/multi-layers using simple processes such as chemical vapor deposition (CVD), chemical bath deposition (CBD), and mechanical and liquid-phase exfoliation processes that simply enhance optoelectronic properties. However, the stability of 2D-NLs is one of the most significant challenges that limits their commercialization. Researchers have been focusing on the stability of 2D-NLs with the aim of developing next-generation solar cells. Easily tunable distinctive 2D-NLs that are based on the synthesis process, surface functional groups, and modification with other materials/hybri...

Electronic Materials Letters, 2012

Nanostructured semiconductors with different morphologies are used widely in various applications in order to enhance their technological advancements compared with the bulk sample. This flourishing nanoscience field has enabled rapid developments that have created numerous opportunities for scienctific advancements with various devices. Considering large environmental impacts such as global warming, problems of nuclear waste storage and nuclear accidents, there is an urgent need for environmentally sustainable energy technologies such as solar cells and fuel cells. In the present paper, the role of nanostructured semiconductors in dyesensitized solar cells (DSSCs) is reviewed entensively. The review discusses the present developmental prospects of DSSCs and the problems associated with its layer materials and propose a method of overcoming these problems.

Advanced Materials, 2011

earned his PhD from Princeton University and then worked as a post-doctoral researcher at the Massachusetts Institute of Technology (MIT) in the Organic and Nanostructured Electronics Laboratory. Currently, he is an Assistant Professor at Michigan State University where he heads the Molecular and Organic Electronics group. His research interests include organic epitaxy, excitonic photophysics, and thin-fi lm photovoltaics. Vladimir Bulović is a Professor of Electrical Engineering at MIT, leading the Organic and Nanostructured Electronics Laboratory and co-directing the MIT-ENI Solar Frontiers Center. His interests include studies of physical properties of organic and organic/ inorganic nanocrystal composites, and development of novel optoelectronic organic and hybrid nanoscale devices.

Angewandte Chemie International Edition, 2008

Current Opinion in Green and Sustainable Chemistry, 2019

Two-dimensional materials provide an excellent example of how the discovery of new material compounds and nanophases can drive sudden and exciting advances in technological applications. Unexpected physico-chemical effects have been reported in 2D-materials, starting from graphene, the first discovered stable 2D compound, and up to the most complex 2D crystals, as hybrid perovskites. Such unexpected properties are induced by the low dimensionality and go well beyond the expected physical changes induced by quantum confinement. In this review, general properties of 2D materials are shortly presented. We focus on the most advanced methods used in material science to design and optimize 2D-systems properties, and report on the most interesting materials recently characterized, including transition metal dichalcogenide monolayers and van der Waals heterostructures. Issues and limitations for 2D design and usage are also highlighted, with possible routes and efforts to optimize electronic and optical properties for energy-related and photovoltaics applications.

SPIE Proceedings, 2005

Light emitting devices based on high-efficiency photoluminescence (PL) fluorescent nanocrystals have been investigated in terms of the generation of light from the structure using a variety of deposition methods. An automated modified layer-by-layer (LbL) self-assembly technique has been employed to produce multilayers of thiol-capped red fluorescing CdTe nanocrystals. Indium-tin-oxide (ITO) and aluminium electrodes were used as the electrodes. Morphological characterization was carried out through Schottky field effect (SFEG) SEM and atomic force microscopy (AFM). The structures built presented clear red electroluminescence (EL) to the naked eye. Turn on voltages were found to be in the range of 3-6 volts while the onset current was in the order of tens of microamperes. The role of structure homogeneity, the presence of pinholes and lifetime extension were features addressed during this investigation. Samples with a lifetime of continuous operation in air longer than 60 minutes and highly stable EL spectra were achieved; EL was visible to the unaided eye, although the brightness was still below the commercial standards and has not yet been qualified.

Journal of Nanomaterials

Since O’Regan and Grätzel’s first report in 1991, dye-sensitized solar cells (DSSCs) appeared immediately as a promising low-cost photovoltaic technology. In fact, though being far less efficient than conventional silicon-based photovoltaics (being the maximum, lab scale prototype reported efficiency around 13%), the simple design of the device and the absence of the strict and expensive manufacturing processes needed for conventional photovoltaics make them attractive in small-power applications especially in low-light conditions, where they outperform their silicon counterparts. Nanomaterials are at the very heart of DSSC, as the success of its design is due to the use of nanostructures at both the anode and the cathode. In this review, we present the state of the art for bothn-type andp-type semiconductors used in the photoelectrodes of DSSCs, showing the evolution of the materials during the 25 years of history of this kind of devices. In the case ofp-type semiconductors, also s...

Nanochemistry and nanomaterials provide numerous opportunities for a new generation of photovoltaics with high solar energy conversion efficiencies at low fabrication cost. Quantum-confined nanomaterials and polymer-inorganic nanocomposites can be tailored to harvest sun light over a broad range of the spectrum, while plasmonic structures offer effective ways to reduce the thickness of lightabsorbing layers. Multiple exciton generation, singlet exciton fission, photon down-conversion, and photon up-conversion realized in nanostructures, create significant interest for harvesting underutilized ultraviolet and currently unutilized infrared photons. Nanochemical interface engineering of nanoparticle surfaces and junction-interfaces enable enhanced charge separation and collection. In this review, we survey these recent advances employed to introduce new concepts for improving the solar energy conversion efficiency, and reduce the device fabrication cost in photovoltaic technologies. The review concludes with a summary of contributions already made by nanochemistry. It then describes the challenges and opportunities in photovoltaics where the chemical community can play a vital role.

Handbook of Research on Solar Energy Systems and Technologies

Solar radiation is plentiful and a clean source of power. However, despite the first practical use of silicon based solar cell more than 50 years ago, it has not been exploited to its full potential due to the high cost of electrical conversion on a per Watt basis. Many new kinds of photovoltaic cells such as multi-junction solar cells dye-sensitized solar cells and organic solar cell incorporating element of nanotechnology have been proposed to increase the efficiency and reduce the cost. Nanotechnology, in the form of quantum dots, nanorods, nanotubes, and grapheme, has been shown to enhance absorption of sunlight, makes low cost flexible solar panels and increases the efficiency of photovoltaic cells. The chapter reviews the state of current photovoltaic cells and challenges it presents. It also discusses the use of nanotechnology in the application of photovoltaic cells and future research directions to improve the efficiency of solar cells and reduce the cost.