High Open-Circuit Voltage Cs2 AgBiBr6 Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Invited for this month cover is the group of Teresa Gatti at the Justus Liebig University (JLU) in Giessen, Germany, the group of Federico Bella at Politecnico di Torino (POLITO), Italy, and the group of Francesco Lamberti at the University of Padova (UNIPD), also in Italy. The image shows how waste tires can be converted in a conductive carbon powder that undergoes a green processing step to produce carbon electrodes for lead-free perovskite solar cells. Similar devices can be employed to harvest indoor light in order to power the Internet of Things (IoT) ecosystem. The Research Article itself is available at 10.1002/cssc.202201590.

High Open-Circuit Voltage Cs2 AgBiBr6 Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Costs and toxicity concerns are at the center of a heated debate regarding the implementation of perovskite solar cells (PSCs) into commercial products. The first bottleneck could be overcome by eliminating the top metal electrode (generally gold) and the underlying hole transporting material and substituting both with one single thick layer of conductive carbon, as in the so-called carbon-based PSCs (C-PSCs). The second issue, related to the presence of lead, can be tackled by resorting to other perovskite structures based on less toxic metallic components. An interesting case is that of the double perovskite Cs2 AgBiBr6 , which at present still lacks the outstanding optoelectronic performances of the lead-based counterparts but is very stable to environmental factors. In this work, the processing of carbon electrodes onto Cs2 AgBiBr6 -based C-PSCs was reported, starting from an additive-free isopropanol ink of a carbon material obtained from the hydrothermal recycling of waste tires and employing a high-throughput ultrasonic spray coating method in normal environmental conditions. Through this highly sustainable approach that ensures a valuable step from an end-of-life to an end-of-waste status for used tires, devices were obtained delivering a record open circuit voltage of 1.293 V, which might in the future represent ultra-cheap solutions to power the indoor Internet of Things ecosystem.

On the Nature of Charge-Injecting Contacts in Organic Field-Effect Transistors.

Organic field-effect transistors (OFETs) are key enabling devices for plastic electronics technology, which has a potentially disruptive impact on a variety of application fields, such as health, safety, and communication. Despite the tremendous advancements in understanding the OFET working mechanisms and device performance, further insights into the complex correlation between the nature of the charge-injecting contacts and the electrical characteristics of devices are still necessary. Here, an in-depth study of the metal-organic interfaces that provides a direct correlation to the performance of OFET devices is reported. The combination of synchrotron X-ray spectroscopy, atomic force microscopy, electron microscopy, and theoretical simulations on two selected electron transport organic semiconductors with tailored chemical structures allows us to gain insights into the nature of the injecting contacts. This multiple analysis repeated at the different stages of contact formation provides a clear picture on the synergy between organic/metal interactions, interfacial morphology, and structural organization of the electrode. The simultaneous synchrotron X-ray experiments and electrical measurements of OFETs in operando uncovers how the nature of the charge-injecting contacts has a direct impact on the injection potential of OFETs.