Solar Cells Incorporating Water/Alcohol-Soluble Electron-Extracting DNA Nanolayers

Deoxyribonucleic acid (DNA) was successfully incorporated as a nanolayer between the bottom indium tin oxide (ITO) transparent electrode and the photoabsorbing film in a polymer solar cell. Upon film optimization and analyses with scanning tunneling spectroscopy/currents, we demonstrate that a 1−6 nm thick DNA stratum functions as an effective electron-extracting layer, leading to strong improvements in rectifying behavior (by 2 orders of magnitude with rectifying ratios reached larger than 103) and in photovoltaic parameters like the open-circuit voltage (VOC from 0.39 to 0.73 V) and power conversion efficiencies (PCEs from ∼2 to ∼5%). The results show that DNA is a very ductile nanomaterial for electronic purposes, paving the way for future exploration in photovoltaic devices combining its electron-extracting properties with its functional and self-assembly behavior. Furthermore, solar cell devices were completely processed at room temperature, and DNA was cast from ecofriendly solvents such as water and alcohol.