K+-Doping Constructs High-Quality Inorganic Sb2(S,Se)3 Semiconductor Film for Efficient Solar Cells With Inspiring Open-Circuit Voltage

Crystalline Sb2(S,Se)3 has attracted considerable attention as light-harvesting material due to its excellent photovoltaic property. Herein, for the first time, K+-assisted deposition technique has been developed for hydrothermal-processed Sb2(S,Se)3 semiconductor film on CdS surface to fabricate high-quality Sb2(S,Se)3/CdS heterojunction. The micro-morphologies (i.e., crystal size, heterojunction structure, element mapping) of the film are investigated through scanning electron microscopy (SEM). The electrical and optical properties are characterized by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and space-charge-limited current (SCLC) methods. Eventually, the K+-doped photovoltaic device displays an encouraging power conversion efficiency (
$\eta \text {)}$
of 8.96%, possessing one of the highest open circuit voltage (
${V}_{\text {oc}}\text {)}$
of 0.69 V with CdS as the single electron transporting layer (ETL). Meanwhile, the reason why the K+-doped device boosts high
${V}_{\text {oc}}$
has also been revealed in the Sb2(S,Se)3 solar cells.