A study of CdTe solar cells using Ga-doped MgxZn1-xO buffer/TCO layers: Simulation and performance analysis

The effect of stacked Ga-doped MgxZn1−xO (GMZO) thin films being the n-partner buffer layer and of the transparent conducting oxide (TCO) layer on the performance of CdTe thin film solar cells has been investigated. The diversity of the electrical and optical properties of GMZO films versus Ga and Mg doping concentrations suggested the use of low-Ga-doped MgxZn1−xO (LGMZO) films as a high resistance transparent buffer layer. Thus, a high-Ga-doped MgxZn1−xO (HGMZO) film is nominated as a transparent TCO layer. In this respect, a (n+)-HGMZO/(n)-LGMZO/(p)-CdTe/MoTe2/Mo suggested structure has been simulated using the Analysis of Microelectronic and Photonic Structures (AMPS-1D) software under the AM1.5G illumination and at a temperature of 300 K. The structure uses the molybdenum ditelluride (MoTe2) layer as a back surface between the CdTe absorber layer and the Mo back contact. The effect of the thickness and the carrier concentration of the LGMZO-buffer, and of the CdTe absorber layers on the CdTe cell performance was investigated. Keywords: CdTe solar cells, Thin films, Ga-doped MgxZn1−xO, AMPS-1

Photo-Programmable Processes in Bithiophene–Azobenzene Monolayers on Gold Probed via Simulations

In this study, we investigate the structural changes, electronic properties, and charge redistribution within azo-bithiophene (Azo-BT)-chemisorbed monolayers under different light stimuli using the density functional theory and molecular dynamics simulations. We consider two types of switches, Azo-BT and BT-Azo, with different arrangements of the Azo and BT blocks counting from the anchor thiol group. The chemisorbed monolayers of pure cis- and trans-isomers with a surface concentration of approximately 2.7 molecules per nm2 are modeled on a gold surface using the classical all-atom molecular dynamics. Our results reveal a significant shrinkage of the BT-Azo layer under UV illumination, whereas the thicknesses of the Azo-BT layer remain comparable for both isomers. This difference in behavior is attributed to the ordering of the trans-molecules in the layers, which is more pronounced for Azo-BT, leading to a narrow distribution of the inclination angle to the gold surface. Conversely, both layers consisting of cis-switches exhibit disorder, resulting in similar brush heights. To study charge transfer within the immobilized layers, we analyze each snapshot of the layer and calculate the mean charge transfer integrals using Nelsen’s algorithm for a number of interacting neighboring molecules. Combining these integrals with reorganization energies defined for the isolated molecules, we evaluate the charge transfer rates and mobilities for electron and hole hopping within the layers at room temperature based on Marcus’ theory. This research offers new perspectives for the innovative design of electrode surface modifications and provides insights into controlling charge transfer within immobilized layers using light triggers. Additionally, we identify molecular properties that are enhanced via specific molecular design, which contributes to the development of more efficient molecular switches for various electronic applications

A New Simplified Algorithm for Real-Time Power Optimization of TCT Interconnected PV Array under Any Mismatch Conditions

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