Sensitive detection of near-infrared (NIR) light enables many important applications in both research and industry. Current organic photodetectors suffer from low NIR sensitivity typically due to early absorption cutoff, low responsivity and/or large dark/noise current under bias. Herein, organic photodetectors based on a novel ultranarrow bandgap non-fullerene acceptor, CO1-4Cl, are presented, showcasing a remarkable responsivity over 0.5 A W-1 in the NIR spectral region (920-960 nm), which is the highest amongst organic photodiodes. By effectively delaying the onset of the space charge limited current and suppressing the shunt leakage current, the optimized devices show a large specific detectivity around 10 12 Jones for NIR spectral region up to 1010 nm, close to that of a commercial Si photodiode. The presented photodetectors can also be integrated in photoplethysmography for real-time heart rate monitoring, suggesting its potential for practical applications. Near-infrared (NIR) light usually corresponds to the region of electromagnetic radiation with wavelength spanning from about 750 nm to 1400 nm. [1] Despite being invisible to human visual perception, NIR sensing finds applications in a variety of technologies, including medical monitoring, [2] quality inspection, [3] machine vision, [4] and bio-imaging. [5] NIR sensing has been conventionally realized with detectors based on single-crystal inorganic semiconductor materials (e.g. Si, Ge, GaInAs), which typically have drawbacks including costly processing, mechanical inflexibility, and sensitivity to temperature. [6-8] Owing to the low cost, solution processing, material tunability, unique structure-property relationships and good mechanical flexibility, organic semiconductors emerged as an exciting candidate for integrated electronics, lighting, solar cells and photodetection. Particularly, photodetectors based on organic semiconductors have witnessed increasing research endeavor, Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff))

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In-depth understanding of the doped and de-doped states of CPE-K, a unique, water-soluble, highly conductive polymer.

A new narrow bandgap non-fullerene electron acceptor was designed, synthesized, and characterized for near-infrared organic photovoltaics. This acceptor was compared to a structurally similar compound with systematically modified side chains,...

Investigation of the physical properties of carbon nanowall (CNW) films is carried out in correlation with the growth time. The structural, electronic, optical and electrical properties of CNW films are investigated using electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, UV–Vis spectroscopy, Hall Effect measurement system, Four Point Probing system, and thermoelectric measurements. Shorter growth time results in thinner CNW films with a densely spaced labyrinth structure, while a longer growth time results in thicker CNW films with a petal structure. These changes in morphology further lead to changes in the structural, optical, and electrical properties of the CNW.

Photoactive Materials Next‐generation photovoltaics will be lightweight, flexible, and (semi)transparent. Highly transparent organic photoactive materials are reported by Thuc‐Quyen Nguyen, Viktor Brus, and co‐workers in article number 2203796. The changes in the fundamental processes in solar cells comprising a near‐IR‐absorbing acceptor and a visible‐light‐absorbing donor are revealed upon dilution of the donor material, paving the way for integrated energy‐harvesting solutions based on semitransparent organic photovoltaics.

In a period of only a few years, the power conversion efficiency of organicinorganic perovskite solar cells has surpassed a value of 24.2%. However, a major drawback is the lack of long-term stability, which is partially related to the dissociation of organic cations under prolonged illumination. This degradation mechanism is not limited to ambient temperatures. At low temperatures (T ¼ 5 K), illumination of methyl ammonium lead iodide (CH 3 NH 3 PbI 3 ) thin films with a photon energy of E ph ¼ 3.4 eV results in the formation of localized trap states located about 100 meV within the bandgap. These light-induced defects are metastable, and annealing at T ≥ 15 K removes the localized states. Defect creation is not limited to polycrystalline perovskites but is also observed in single-crystal CH 3 NH 3 PbI 3 . The experimental data are discussed in terms of a two-level model where the metastable state is separated from the annealed state by an energy barrier.

The determination of the voltage‐dependent density of free charge carriers via capacitance spectroscopy is considered an important step in the analysis of emerging photovoltaic technologies, such as organic and perovskite solar cells. In particular, an intimate knowledge of the density of free charge carriers is required for the determination of crucial parameters such as the effective mobility, charge carrier lifetime, nongeminate recombination coefficients, average extraction times, and competition factors. Hence, it is paramount to verify the validity of the commonly employed approaches to obtain the density of free charge carriers. The advantages, drawbacks, and limitations of the most common approaches are investigated in detail and strategies to mitigate misleading values are explored. To this end, two types of nonfullerene organic solar cells based on a PTB7‐Th:ITIC‐2F blend and a PM6:Y6 blend, respectively, are used as a case study to assess how subsequent analyses of the nongeminate recombination dynamics depend on the chosen approach to calculate the density of free charge carriers via capacitance spectroscopy.