The energy-down-shift effect of Cd0.5Zn0.5S–ZnS core–shell quantum dots on power-conversion-efficiency enhancement in silicon solar cells

Abstract

We found that Cd_0.5Zn_0.5S–ZnS core (4.2 nm in diameter)–shell (1.2 nm in thickness) quantum dots (QDs) demonstrated a typical energy-down-shift (2.76–4.96 → 2.81 eV), which absorb ultra-violet (UV) light (250–450 nm in wavelength) and emit blue visible light (∼442 nm in wavelength). They showed the quantum yield of ∼80% and their coating on the SiN_X film textured p-type silicon solar-cells enhanced the external-quantum-efficiency (EQE) of ∼30% at 300–450 nm in wavelength, thereby enhancing the short-circuit-current-density (J_SC) of ∼2.23 mA cm⁻² and the power-conversion-efficiency (PCE) of ∼1.08% (relatively ∼6.04% increase compared with the reference without QDs for p-type silicon solar-cells). In particular, the PCE peaked at a specific coating thickness of the Cd_0.5Zn_0.5S–ZnS core–shell QD layer; i.e., the 1.08% PCE enhancement at the 8.8 nm thick QD layer.