Carrier-Selective Contacts for Tungsten Disulfide Photovoltaics

Transition Metal Dichalcogenides (TMDs) have strong light-matter interactions that are promising for high-specific power solar applications, ranging from wearable electronics to space. Many TMD solar devices have p-n or Schottky junction architectures with recombination losses at the TMD and metal electrode interface that limit the carrier collection efficiency. To improve carrier separation and collection, we take inspiration from the highest-efficiency perovskite solar cells, which have carrier-selective contacts. We demonstrate a vertical solar cell geometry consisting of a 10-nm-thick tungsten disulfide (WS2) absorber layer sandwiched between a C60 electron transport layer and PTAA hole transport layer. This device exhibits an AM1.5G open-circuit voltage of 523 mV and power conversion efficiency of 2.4%. Through open-circuit voltage limit calculations, we suggest next steps for improving the WS2 photovoltaic performance towards the voltage limit.