Emitter/Absorber Interface Design Strategies for Se Solar Cells

Selenium (Se) has garnered significant attention as a promising wide-bandgap material for photovoltaic applications. However, progress in enhancing the efficiency of Se solar cells remains limited. This study addresses this challenge by targeting the critical emitter/Se absorber interface for performance improvement. Through numerical simulations, we systematically investigate the impact of key interface properties—specifically, band alignment and defect characteristics—on device performance. Our results demonstrate that a slight positive conduction band offset (CBO) effectively strengthens absorber band bending and reduces hole concentration at the Se surface. Furthermore, minimizing interface defect density or incorporating donor-type defects significantly alleviates interfacial recombination. Building on these findings, we propose a novel interface passivation strategy employing an ultra-thin dielectric layer engineered with positive fixed charges or hydrogen atoms. This approach is anticipated to substantially suppress recombination losses and enhance the performance of Se solar cells, facilitating their broader adoption in photovoltaics.