Recently, organolead halide-based perovskites have emerged as promising materials for optoelectronic applications, particularly for photovoltaics, photodetectors, and lasing, with low cost and high performance. Meanwhile, nanoscale photodetectors have attracted tremendous attention toward realizing miniaturized optoelectronic systems, as they offer high sensitivity, ultrafast response, and the capability to detect beyond the diffraction limit. Here we report high-performance nanoscale-patterned perovskite photodetectors implemented by nanoimprint lithography (NIL). The spin-coated lead methylammonium triiodide perovskite shows improved crystallinity and optical properties after NIL. The nanoimprinted metal-semiconductor-metal photodetectors demonstrate significantly improved performance compared to the nonimprinted conventional thin-film devices. The effects of NIL pattern geometries on the optoelectronic characteristics were studied, and the nanograting pattern based photodetectors demonstrated the best performance, showing approximately 35 times improvement on responsivity and 7 times improvement on on/off ratio compared with the nonimprinted devices. The high performance of NIL-nanograting photodetectors likely results from high crystallinity and favored nanostructure morphology, which contribute to higher mobility, longer diffusion length, and better photon absorption. Our results have demonstrated that the NIL is a cost-effective method to fabricate high-performance perovskite nanoscale optoelectronic devices, which may be suitable for manufacturing of high-density perovskite nanophotodetector arrays and to provide integration with state-of-the-art electronic circuits.

The inversion field-effect transistor is the basic device of modern microelectronics and is nowadays used more than a billion times on every state-of-the-art computer chip. In the future, this rigid technology will be complemented by flexible electronics produced at extremely low cost. Organic field-effect transistors have the potential to be the basic device for flexible electronics, but still need much improvement. In particular, despite more than 20 years of research, organic inversion mode transistors have not been reported so far. Here we discuss the first realization of organic inversion transistors and the optimization of organic depletion transistors by our organic doping technology. We show that the transistor parameters—in particular, the threshold voltage and the ON/OFF ratio—can be controlled by the doping concentration and the thickness of the transistor channel. Injection of minority carriers into the doped transistor channel is achieved by doped contacts, which allows forming an inversion layer.

Metal halide perovskites (MHPs) have rapidly emerged as leading contenders in photovoltaic technology and other optoelectronic applications owing to their outstanding optoelectronic properties. After a decade of intense research, an in-depth understanding of the charge carrier transport in MHPs is still an active topic of debate. In this Perspective, we discuss the current state of the field by summarizing the most extensively studied carrier transport mechanisms, such as electron–phonon scattering limited dynamics, ferroelectric effects, Rashba-type band splitting, and polaronic transport. We further extensively discuss the emerging experimental and computational evidence for dominant polaronic carrier dynamics in MHPs. Focusing on both small and large polarons, we explore the fundamental aspects of their motion through the lattice, protecting the photogenerated charge carriers from the recombination process. Finally, we outline different physical and chemical approaches considered recently to study and exploit the polaron transport in MHPs.

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Hydrofluoroethers are shown to be benign solvents for a wide variety of organic electronic materials, even at extreme conditions such as boiling temperature (see figure). Coupled with fluorous functional materials they open new frontiers for “green” materials processing that can be readily adopted by industry.

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The concept of chemical orthogonality has long been practiced in the field of inorganic semiconductor fabrication, where it is necessary to deposit and remove a layer of photoresist without damaging the underlying layers. However, these processes involving light sensitive polymers often damage organic materials, preventing the use of photolithography to pattern organic electronic devices. In this article we show that new photoresist materials that are orthogonal to organics allow the fabrication of complex devices, such as hybrid organic/inorganic circuitry and full-colour organic displays. The examples demonstrate that properly designed photoresists enable the fabrication of organic electronic devices using existing infrastructure. Results and discussionAs a first target, we fabricated top-contact OTFTs having channel lengths which are difficult to achieve with conventional

Toxic gases are produced during the burning of fossil fuels. Room temperature (RT) fast detection of toxic gases is still challenging. Recently, MoS transition metal dichalcogenides have sparked great attention in the research community due to their performance in gas sensing applications. However, MoS based gas sensors still suffer from long response and recovery times, especially at RT. Considering this challenge, here, we report photoactivated highly reversible and fast detection of NO sensors at room temperature (RT) by using mixed in-plane and edge-enriched p-MoS flakes (mixed MoS). The sensor showed fast response with good sensitivity of ∼10.36% for 10 ppm of NO at RT without complete recovery. However, complete recovery was obtained with better sensor performance under UV light illumination at RT. The UV assisted NO sensing showed improved performance in terms of fast response and recovery kinetics with enhanced sensitivity to 10 ppm NO concentration. The sensor performance is also investigated under thermal energy, and a better sensor performance with reduced sensitivity and high selectivity toward NO was observed. A detailed gas sensing mechanism based on the density functional theory (DFT) calculations for favorable NO adsorption sites on in-plane and edge-enriched MoS flakes is proposed. This study revealed the role of favorable adsorption sites in MoS flakes for the enhanced interaction of target gases and developed a highly sensitive, reversible, and fast gas sensor for next-generation toxic gases at room temperature.