Phys.org March 12, 2021 An international team of researchers (USA – Clemson University, Los Alamos National Laboratory, University of Alabama, China) observed the ultrafast dynamics of trapped carriers in organic methyl ammonium lead halide perovskite thin films by ultrafast photocurrent spectroscopy. Upon ultrafast laser excitation, trapped carriers followed a phonon assisted tunneling mechanism and a hopping transport mechanism along ultra-shallow to shallow trap states ranging from 1.72–11.51 millielectronvolts. They validated the transport mechanisms by highlighting trap state dynamics, including trapping rates, de-trapping rates and trap properties, such as trap density, trap levels, and capture-cross sections. The work establishes a foundation […]
Tag Archives: Solar energy
New research could boost a solar-powered fuel made by splitting water
Science Daily March 10, 2021 Altering crystal facets exposed on the surface of photoelectrodes used for solar fuel production has been a major strategy for optimizing their properties. There are numerous ways to terminate the surface even for the same facet, which can considerably alter the photoelectrode properties. A team of researchers in the US (University of Wisconsin, University of Chicago, Brookhaven National Laboratory, Stony Brook University, Argonne National Laboratory) investigated using tightly integrated experimental and computational investigations of epitaxial BiVO4 photoelectrodes with vanadium- and bismuth-rich (010) facets. The study demonstrated that even for the same facet the surface Bi:V […]
Solar-powered system extracts drinkable water from ‘dry’ air
MIT News October 14, 2020 An international team of researchers (USA – MIT, University of Utah, South Korea) had developed a similar device as a proof of concept. The system, harnessed temperature difference within the device to allow an adsorbent material to draw in moisture from the air at night and release it the next day. The current work has demonstrated adsorption-based solar-thermal-driven atmospheric water harvesting (AWH) in arid regions, but the daily water productivity remained low. They developed and tested a dual-stage AWH device with optimized transport. By recovering the latent heat of condensation of the top stage and […]
Study offers new insights for sun-gathering technologies
Phys.org August 24, 2020 The direct integration of electrocatalysts with photovoltaic materials provides a strategy to photoelectrochemically power chemical transformations and store intermittent solar energy as fuels. Researchers at the Arizona State University highlight how optical and electrochemical characterization techniques can be coupled with structural information to address to what extent does a selected electrocatalytic coating screen photons from reaching the underlying photovoltaic; coating layers contribute to photocurrent production; and are relatively high or low loadings of catalytic sites advantageous. They used p-type gallium phosphide semiconductor that is interfaced with cobalt porphyrin hydrogen evolution reaction catalysts. Experimental techniques can likely […]
Efficient Off-Grid Power, After the Sun Sets
Optics and Photonics August 19, 2020 An international team of researchers (USA – Stanford, Israel) analyzed the basic thermodynamics of a heat engine, with the hot side under the roof and the top of the roof radiating thermal energy out into the environment. They developed models to maximize the amount of electrical power generated for various temperature gradients. The team’s design for a nighttime power generator would occupy a rooftop area of 1 m2. It incorporates a radiative emitting panel, a state-of-the-art TEG made of metal alloy, and a heat sink, with radiation shields and insulative pegs to reduce radiative […]
Engineers make a promising material stable enough for use in solar cells
Science Daily April 29, 2020 Inherently soft crystal lattice of Halide perovskites allows greater tolerance to lattice mismatch, making them promising for heterostructure formation and semiconductor integration. However, their high intrinsic ion mobility, which leads to interdiffusion and large junction widths and their poor chemical stability, epitaxial growth of atomically sharp heterostructures of halide perovskites has not yet been achieved. An international team of researchers (USA – Perdue University, MIT, UC Berkeley, Lawrence Berkeley National Laboratory, China) has developed a strategy to substantially inhibit in-plane ion diffusion in two-dimensional halide perovskites by incorporating rigid π-conjugated organic ligands. They have demonstrated […]
After 40 Years of Hunting, Scientists Identify a Key Flaw in Solar Panel Efficiency
Science Alert February 13, 2020 Silicon solar cells containing boron and oxygen suffer from Light Induced Degradation which could be responsible for the 2 percent efficiency drop that solar cells can see in the first hours of use. Using deep level transient spectroscopy and photoluminescence an international team of researchers (UK, Portugal, Belarus, Australia) has observed the conversion of a deep boron-di-oxygen-related donor state into a shallow acceptor which correlates with the change in the lifetime of minority carriers in the silicon. They propose structures of the BsO2 defect which match the experimental findings and hypothesize that the dominant recombination […]
Anti-solar cells: A photovoltaic cell that works at night
Science Daily January 29, 2020 Photovoltaics can generate electricity during daylight hours. Researchers at the University of Maryland consider an alternative photovoltaic concept that uses the earth as a heat source and the night sky as a heat sink, resulting in a “nighttime photovoltaic cell” that employs thermoradiative photovoltaics and concepts from the advancing field of radiative cooling. In this perspective, they discuss the principles of thermoradiative photovoltaics, the theoretical limits of applying this concept to coupling with deep space, the potential of advanced radiative cooling techniques to enhance their performance, and a discussion of the practical limits, scalability, and […]
Tweaks behind the rebirth of nearly discarded organic solar technologies
Science Daily December 19, 2019 Unlike silicon solar technology, non-fullerene acceptors (NFAs) can be shaped, made semi-transparent or colored and fine-tuned to free up and move electrons to generate electricity. Researchers at Georgia Institute of Technology have modeled tiny tweaks to molecular shapes and calculated corresponding energy conversion in a common NFA electron donor/acceptor pairing. Improved performance came from tweaks to a tiny component, a methoxy group, on the acceptor, and two positions out of four possible positions it took boosted the conversion of light into electricity from 6% to 12%…read more. Open Access TECHNICAL ARTICLE
Daylight damage to photovoltaics
Science Daily December 2, 2019 The cumulative damage from the sun tends to erode efficiency of a new class of solar cells that utilizes layers of carbon-based polymers. Based on the results of current-voltage curves, impedance spectroscopy, and UV-VIS spectrophotometry, researchers in Japan have determined that exposure to the sun’s ultraviolet light can damage the fragile organic molecules in the semiconducting layer just like it damages human skin. When some sulfur atoms in the materials get replaced by oxygen atoms from the atmosphere, the molecules no longer function as intended. The degradation products from solar damage increased the electrical resistance […]