White Light to Near‐IR Chargeable Single Component Photocapacitor Based on Donor‐chromophore‐Acceptor Dyes

Power sources that can be charged anytime and anywhere are highly desirable for mobile devices. The most suitable device for achieving such wireless charging is a photocapacitor, which utilizes light as a renewable energy source instead of electricity from the grid. Sunlight on Earth is intermittent and unstable, so photocapacitors that can be charged by the day or room light and near-infrared (near-IR) radiation are needed to ensure the uninterrupted operation of the equipment. We employ a single dye-sensitized solar cell as a photocapacitor without adding any additional charge storage components to reduce the cost and complexity of device manufacturing. To realize such photocapacitors, this work presents a family of new isoindigo-based D-π-A photoactive dyes with good visible and near-IR absorption. Notably, LF15 has a higher molar absorbance coefficient and enhanced dye-loading than LF23, which is consistent with the higher photocurrent of photocapacitors based on the former. Photocapacitors based on these three dyes achieve photovoltages up to 0.74 V, area-specific capacitances of 2.87 mF cm-2 , and excellent charge-discharge stability. The devices can be charged in both visible and near-IR conditions, exhibiting typical capacitor behavior.