Cover story: Zhang WL, Çakıroğlu O, Al-Enizi A, Nafady A, Gan XT et al. Solvent-free fabrication of broadband WS₂ photodetectors on paper. Opto-Electron Adv 6, 220101 (2023)

Discarded electronic devices are a fast-growing source of waste. One way to mitigate the problem could be to the use of components that are made with resources that are easy to dispose of responsibly. Paper-based devices can be a solution to achieve both low-cost and biodegradable electronic components tackling the problems of disposable electronics. Here, research groups of Professor Andres Castellanos-Gomez from Materials Science Institute of Madrid, Spanish National Research Council, Spain and Prof. Yong Xie from Xidian University, China, demonstrated the fabrication of semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors. This solvent-free method is used to deposit a tungsten disulfide WS₂ film on paper exhibiting a remarkable photoresponse in the order of ~10 mA W⁻¹ at a bias voltage of 10 V over a broad spectral range from ultraviolet (365 nm) to near-infrared (940 nm). Their responsivity value is very similar to commercially available silicon photodetectors. In addition, a WS₂ photodetector with the narrow channel distance is fabricated on paper using interdigitated Au electrodes, achieving a responsivity of ~200 mA W⁻¹ at 5 V bias. Finally, they construct an optical spectrometer using a paper-based WS₂ device to demonstrate its potential application in sensitive photodetection components. The present work could promote the development of cost-effective disposable photodetection devices.