Semi-transparent luminescent solar concentrators window panels based on methylammonium lead bromide perovskite coatings are fabricated. It is shown that spraying as a large-scale fabrication technique delivers samples with comparable characteristics with those prepared by the physical vapor deposition or spin-coating methods. Three mirrorless, mirrored, and gaped-mirror configurations are designed for the current–voltage evaluation of the samples. According to our results, perovskite coating of glass slides with different film thickness leads to a 16% to 45% increase in the output electrical power. A gaped-mirror arrangement, through separating the bottom mirror in these devices, is introduced to mimic a typical double-glazed window panel for increasing the output efficiency. Moreover, it is demonstrated that fabricated luminescent concentrators can perform under different directional placements, which promises their widespread application in greenhouses and electrical vehicles.
Intrinsic losses, including below-band gap, thermalization, mismatch angle, Carnot, and emission, are investigated in a structure of quantum dot intermediate band solar cells (QD-IBSCs). Owing to the excellent irradiance resistance of III-nitride material and reduction of Auger recombination processes, diluted nitride of InAsN is considered as quantum dot (QD) material. Then, AlPSb is considered as the barrier material according to the principles of intermediate band operation and the band structures of InAsN and AlPSb in which phosphorous molar fraction is optimized by the minimizing of total intrinsic losses. The engineering of QD size and period offers a way to engineer the confined energy levels within the QDs and ultimately the intrinsic losses. This was carried out with the help of a finite element model in the context of a three-dimensional Schrödinger equation created by means of MATLAB software and tight binding method, resulting in the minimum intrinsic loss of 55.18% for the InAs0.995N0.005 / AlP0.7 Sb0.3 QD-IBSC at 1-sun concentration.
The uses of solar energy instead of fossil fuels to supply the global energy demand demonstrate the importance of developing solar cells. Among all solar cells, colloidal quantum dot solar cells have attracted particular attention due to their easy fabrication, size control, low cost, and flexibility. The depleted heterostructure solar cell is introduced and simulated using quantum dots of CdS and TiO2 layers. Then, the Schrödinger equation is solved in the spherical polar coordinate and using the obtained eigenfunctions and eigenvalues, the absorption coefficient of other structural parameters are obtained by finite-difference time-domain method. Then solving Maxwell and Poisson equations using the electric field emitted from sunlight radiation, the generation rates of carriers and the current density and other characteristics of the solar cell based on introduced structure are obtained. For studied structures, the obtained optimum results are Jsc ≈ 15 mA / cm2 and η ≈ 7 % . The obtained values are relatively good in comparison with the experimental results for similar materials.
Large built-in piezoelectric fields in nitride nanostructures, because of their wurtzite structure, induce a spatial
seperation between confined electrons and holes and lead to formation of electric dipoles. This paper investigates
the effects of exciton-exciton interaction as a dipolar interaction in a GaN/AlxGa1-xN microdisk. We show how
this interaction result in biexciton binding energies in the meV energy range. Also we study the effect of disk
radius on exciton binding energy. Results show that the exciton binding energy in smaller disks, is larger than
the bigger one.
In this work the capacitance of AlGaN/GaN heterostructure in presence of InN quantum dots has been
studied. This calculation has been done for different InN quantum Dot size, energy dispersion and in
different temperatures. The presence of InN quantum dot will cause a negative differential capacitance
which can evidence the position of quantum dots in the structures. Our calculation results show this
negative differential capacitance is much higher at low temperature and for quantum dots with low energy
and higher size dispersion.
Conference Committee Involvement (1)
Third International Conference on Photonic Solutions