High-throughput method to deposit continuous composition spread Sb2(SexS1 - x)3 thin film for photovoltaic application

Sb-2(SexS1 (-) (x))(3) alloy materials with tunable bandgaps combining the advantages of Sb2S3 and Sb2Se3 showed high potential in low cost, non-toxicity, and high stability solar cells. The composition dependence of device performance becomes indispensable to study. However, traditional approaches often implement 1 composition at a time, which easily lead to long period and systematic errors. The present work developed a high-throughput experimental method, close-space dual-plane-source evaporation (CDE) method, to successfully deposit continuous composition spread Sb-2(SexS1 (-) (x))(3) library at 1 time. On the surface of the obtained film, the x value of Se content evolved from 0.09 to 0.84 by a series of complementary characterizations. At depth direction, the alloy film kept high crystallinity and composition consistency. Solar cell arrays (19 x 6) were fabricated to investigate the relationship between compositions and performances. As the increase of Se content, the conversion efficiency first increased from 1.8% to 5.6% and then decreased to 5%. The V-oc and J(sc) demonstrated an opposite evolution trend. The champion device with the composition of Sb-2(Se0.68S0.32)(3) achieved the V-oc and J(sc) trade-off exceeding the performances of Sb2S3 (2.43%) and Sb2Se3 (4.97%) devices. Cryogenic and transient characterizations were utilized to investigate the distinct performance evolution mechanism. There existed shallow defect levels in Se-rich alloys and deep defects in sulfur-rich ones. The widely tuned absorber compositions combined with distinct defect characters induced to the large variation of device performance. The present continuous composition spread Sb-2(SexS1 (-) (x))(3) film and their CDE fabrication technique were expected to efficiently screen materials and promote the development of antimony chalcogenide solar cells.