Nanostructure-Based CZGS/CZGSe Multiple Quantum Wells Could Sense Wider Solar Spectrum to Enhance Light-Harvesting Efficiency

Nanostructures in kesterite solar cells are incorporated for performance enhancement. As high recombination limits the efficiency of kesterite-based CZTS/Se solar cell, substituting Ge for Sn as Cu-Zn-Ge-S/Se (CZGS/Se) increases the optical characteristics and solar cell overall performance. This research analyses multi-quantum-well solar cell (MQWSC) using Cu-Zn-Ge-S as a barrier material and Cu-Zn-Ge-Se as a well material. Introducing quantum wells (QWs) as (2, 10, 20, 30, 40, 50, 70, 100 QWs) in CZGS kesterite groups highlights the novelty of device. To enhance the performance, its optic, electric, and structural characteristics are widely researched across nanostructures. An examination of the carrier dynamics of the device is carried out by varying various parameters. By introducing various loss mechanisms, including deep defect and shallow defect, the device's worst case operation is also evaluated. A remarkable efficiency of 29% without defect and 20% with defective states was obtained from the proposed structure, which signifies new route to facilitate the performance of photovoltaic (PV) cells for the next generation.