We have realized a high-detection-efficiency photon number resolving detector at an operating wavelength of about 850 nm. The detector consists of a titanium superconducting transition edge sensor in an optical cavity, which is directly coupled to an optical fiber using an approximately 300-nm gap. The gap reduces the sensitive area and heat capacity of the device, leading to high photon number resolution of 0.42 eV without sacrificing detection efficiency or signal response speed. Wavelength dependent efficiency in fiber-coupled devices, which is due to optical interference between the fiber and the device, is also decreased to less than 1% in this configuration. The overall system detection efficiency is 98%±1% at wavelengths of around 850 nm, which is the highest value ever reported in this wavelength range.
Organic semiconductors (OSCs) are important active materials for the fabrication of next-generation organic-based electronics. However, the development of n-type OSCs lags behind that of p-type OSCs in terms of charge-carrier mobility and environmental stability. This is due to the absence of molecular designs that satisfy the requirements. The present study describes the design and synthesis of n-type OSCs based on challenging molecular features involving a π-electron core containing electronegative N atoms and substituents. The unique π-electron system simultaneously reinforces both electronic and structural interactions. The current n-type OSCs exhibit high electron mobilities with high reliability, atmospheric stability, and robustness against environmental and heat stresses and are superior to other existing n-type OSCs. This molecular design represents a rational strategy for the development of high-end organic-based electronics.
Significant progress has been made in both molecular design and fundamental scientific understanding of organic semiconductors (OSCs) in recent years. Suitable charge-carrier mobilities (μ) have been obtained by many high-performance OSCs (μ > 10 cm 2 V −1 s −1 ), but drawbacks remain, including low solution processability and poor thermal durability. In addition, since aggregation of OSCs involves weak intermolecular interactions, the molecules are perpetually in thermal motion, even in the solid state, which disrupts charge-carrier transport. These issues limit potential applications of OSCs. The present work examines a molecular design for hole-transporting (p-type) OSCs based on the "bent-shaped" geometry with specific molecular orbital configurations, which aims to enhance effective intermolecular orbital overlaps, stabilize crystal phases, suppress detrimental molecular motions in the solid state, and improve solution processability. The results indicated that such OSCs have high μ and suitable solution processability, and are resistant to ambient and thermal conditions, making them suitable for practical applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.