Direct Integration of Perovskite Solar Cells with Carbon Fiber Substrates.

Integrating photovoltaic devices onto the surface of carbon-fiber-reinforced polymer substrates should create materials with high mechanical strength that are also able to generate electrical power. Such devices are anticipated to find ready applications as structural, energy-harvesting systems in both the automotive and aeronautical sectors. Here, the fabrication of triple-cation perovskite n-i-p solar cells onto the surface of planarized carbon-fiber-reinforced polymer substrates is demonstrated, with devices utilizing a transparent top ITO contact. These devices also contain a "wrinkled" SiO2 interlayer placed between the device and substrate that alleviates thermally induced cracking of the bottom ITO layer. Devices are found to have a maximum stabilized power conversion efficiency of 14.5% and a specific power (power per weight) of 21.4 W g-1 (without encapsulation), making them highly suitable for mobile power applications.

Nonplanar Spray-Coated Perovskite Solar Cells.

Spray coating is an industrially mature technique used to deposit thin films that combines high throughput with the ability to coat nonplanar surfaces. Here, we explore the use of ultrasonic spray coating to fabricate perovskite solar cells (PSCs) over rigid, nonplanar surfaces without problems caused by solution dewetting and subsequent "run-off". Encouragingly, we find that PSCs can be spray-coated using our processes onto glass substrates held at angles of inclination up to 45° away from the horizontal, with such devices having comparable power conversion efficiencies (up to 18.3%) to those spray-cast onto horizontal substrates. Having established that our process can be used to create PSCs on surfaces that are not horizontal, we fabricate devices over a convex glass substrate, with devices having a maximum power conversion efficiency of 12.5%. To our best knowledge, this study represents the first demonstration of a rigid, curved perovskite solar cell. The integration of perovskite photovoltaics onto curved surfaces will likely find direct applications in the aerospace and automotive sectors.

Gas-Assisted Spray Coating of Perovskite Solar Cells Incorporating Sprayed Self-Assembled Monolayers.

Self-assembled monolayers (SAMs) are becoming widely utilized as hole-selective layers in high-performance p-i-n architecture perovskite solar cells. Ultrasonic spray coating and airbrush coating are demonstrated here as effective methods to deposit MeO-2PACz; a carbazole-based SAM. Potential dewetting of hybrid perovskite precursor solutions from this layer is overcome using optimized solvent rinsing protocols. The use of air-knife gas-quenching is then explored to rapidly remove the volatile solvent from an MAPbI3 precursor film spray-coated onto an MeO-2PACz SAM, allowing fabrication of p-i-n devices with power conversion efficiencies in excess of 20%, with all other layers thermally evaporated. This combination of deposition techniques is consistent with a rapid, roll-to-roll manufacturing process for the fabrication of large-area solar cells.