Engineering topics

Rijal, Suman

Publications and source records attributed to Rijal, Suman.

3 records

DOE OSTI2023

Water-Assisted Lift-Off Process for Flexible CdTe Solar Cells

In recent years, various lift-off methods have been developed to fabricate lightweight and flexible cadmium telluride (CdTe)-based solar cells. In this work, we report flexible cadmium sulfide (CdS)/CdTe solar cells using a water-assisted lift-off approach. Here we demonstrate that an additional cadmium chloride treatment for the CdS film is critical to improve the grain size of CdS and the post-deposited CdTe film and the electron conductivity of the CdS film. As a result, the quality of the CdS/CdTe front junction is significantly improved with reduced nonradiative recombination. Finally, our lightweight and flexible polycrystalline CdTe solar cells demonstrate a champion power conversion efficiency of 12.6%.

14 SOLAR ENERGY↗

DOE OSTI2022

Post‐Annealing Treatment on Hydrothermally Grown Antimony Sulfoselenide Thin Films for Efficient Solar Cells

Herein, antimony sulfoselenide (Sb 2 (S, Se) 3 ) thin‐film solar cells are fabricated by a hydrothermal method followed by a post‐deposition annealing process at different temperatures and the impact of the annealing temperature on the morphological, structural, optoelectronic, and defect properties of the hydrothermally grown Sb 2 (S, Se) 3 films is investigated. It is found that a proper annealing temperature leads to high‐quality Sb 2 (S, Se) 3 films with large crystal grains, high crystallinity, preferred crystal orientation, smooth and uniform morphology, and reduced defect density. These results show that suppressing deep‐level defects is crucial to enhance solar cell performance. After optimizing the annealing process, Sb 2 (S, Se) 3 solar cells with an improved power conversion efficiency 2.04 to 8.48% are obtained.

14 SOLAR ENERGY↗

DOE OSTI2022

Bifacial CdTe Solar Cells with Copper Chromium Oxide Back-Buffer Layer

Bifacial solar cells have the potential to maintain energy output higher than monofacial devices under unfavorable weather conditions. A transparent back-buffer layer which can passivate the interface and improve the minority carrier lifetime is critical in CdTe-based bifacial devices. Herein, solution-processed Cu x Cr y O z as a promising back-buffer for CdTe/CdS solar cells is demonstrated. The carrier lifetimes measured at the front and back of the device are 31.2 and 3.1 ns, respectively, which correspond to an increase of ≈38% and 138%, respectively, compared to the reference device. This dramatic improvement in lifetime results in a 100% increase in short-circuit current measured with backside illumination. The best bifacial device has efficiencies 7.6% and 12.5%, respectively, from back and front illumination, yielding a bifaciality factor of 0.60.

14 SOLAR ENERGY↗