A coupled PbS quantum dot film and a PSBTBT:PCBM bulk heterojunction layer contribute comparable photocurrent in a new stacked solar‐cell architecture with sensitivity in the near infrared and an efficiency >4%. With a focus on the energy level alignment between components, time‐resolved microwave photoconductivity is used to elucidate the charge transport pathways for electrons and holes.

Electroreflectance spectroscopy was used to study the effect of InxGa1−xAs capping layer on InAs quantum dots grown by metalorganic chemical vapor deposition. The optical transitions of the quantum dots and the InxGa1−xAs capping layer were well resolved. The energy shifts in the InxGa1−xAs capping layer show a different trend as compared to a series of referent InxGa1−xAs quantum wells. These results support the concept of strain-driven alloy decomposition during the InxGa1−xAs layer overgrowth.