The growing need for 'green' energy sources combined with silicon solar cells' stagnating power conversion efficiencies have lead to a keen search for an alternative to silicon that would bring about a major change. Perovskite solar cell technology, boasting potential for high efficiency, low-cost scalable photovoltaic solar cells, may just be a suitable contender in this race. Perovskites, a class of materials that share a similar structure, display a myriad of exciting properties that position them as attractive candidates for enabling low-cost, efficient photovoltaics that could even be sprayed onto rooftops and various other surfaces.
Scientists have now demonstrated in detail how chemical purity of perovskite precursors can affect the morphology of thin-film perovskite layers. While most studies concentrate on the exploration of processing conditions, the research team has investigated the purity levels of common perovskite precursor solutions and found a number of impurities that are critically important toward controlling the crystallization of perovskites. They observed that impurities that formed during the preparation of perovskite precursor solutions initiate formation of PbHPO3 nanoparticles, which helps to growth larger perovskite crystal grains resulting in higher solar cells efficiency.
Solar cells absorb incoming sunlight and convert a part of photon energy into electricity. The remainder of photon energy is dissipated as heat. Although the idea is rather counter-intuitive, 'reverse solar cell' systems can also generate electric power by emitting rather than absorbing photons. Such systems - known as thermoradiative cells - generate voltage and electric power via non-equilibrium thermal radiation of infrared photons. Thermoradiative cells offer an opportunity to generate clean energy by harvesting radiation from largely untapped terrestrial thermal emission sources, potentially including the Earth itself.
Newly developed nanocomposites possess efficient photothermic properties for highly targeted interfacial phase transition reactions that are synergistically favorable for seawater catalysis and desalination. The nanocomposites are seawater and photostable for practical solar conversion of seawater to simultaneously produce clean energy and water. This work defines the forefront of plasmonic photothermic technology, which is vastly untapped and has broad implications in other fields.
Although developed only recently, inorganic halide perovskite quantum dot systems have exhibited comparable and even better performances than traditional quantum dots in many fields. They are expected to be applied in display and lighting technologies. Researchers now have reported an interesting cyclable surface dissolution and recrystallization phenomenon of inorganic perovskite crystals. This allows them to freely change size between nanometer and micrometer scales, and can be used to healing the defects inside perovskite films and hence improve the performances of optoelectronic devices.
The development of perovskite solar cells, first reported in 2009 (and with a record power conversion efficiency of 20.1 percent so far), is a possible route towards high efficiency photovoltaics that are also cost-effectiveness, owing to to their easy-processing from solution. Question marks have however remained on their stability. Now, researchers report the world's first nanorod-based perovskite solar module. In addition to high efficiency, these perovskite solar modules also show remarkable and improved shelf life.
Researchers have integrated a biocompatible silk fibroin with a mesh of silver nanowires to achieve a flexible, transparent, and biodegradable substrate for efficient plastic solar cell. The most common flexible substrates used for flexible solar cells so far have been synthetic polymers such as PET and PEN. However, if organic solar cells are to be applied onto clothes and other soft surfaces, some of which come into direct contact with skin, they are required to be human-compatible, non-toxic and non-irritable.
In recent years, polymer solar cells have drawn considerable research interest due to their attractive features including flexibility, semi-transparency, and manufacturability using cost-effective continuous printing processes. However, one challenge limiting their commercialization is the relatively low power conversion efficiency when compared to inorganic solar cells. New work shows that low bandgap polymer solar cells with high efficiency of 5.5% can be fabricated using nanoimprint lithography.