Germanium Quantum Dot Grätzel‐Type Solar Cell

Solar cells fabricated from sustainable quantum dot materials are currentlynot commercially available, but ongoing research provides a steady increasein efficiency and stability of laboratory devices. In this work, the firstgermanium quantum dot solar cell made with a gas aggregation nanoparticlesource is presented. UV–vis spectroscopy reveals quantum confinement, andthe spectral response of the germanium quantum dot Grätzel-type solar cellconfirms the presence of large and small band gap optical absorption due toa mix of particle sizes. Some of the particles are small enough to havesubstantial quantum confinement while others are so large that they havebulk-like properties. The efficiency of the germanium quantum dot solar cellsis very low but could reach 1% if the formation of germanium oxide layers isavoided in future experiments. This first quantum dot solar cell made with agas aggregation nanoparticle source demonstrates, as a proof of concept, thetechnological potential for research and applications combining the fields ofphotovoltaics and gas aggregation nanoparticle sources.