Organic photodetectors (OPDs) are promising candidates for next‐generation light sensors as they combine unique material properties with high‐level performance in converting photons into electrical signals. However, low‐level light detection with OPD is often limited by device dark current. Here, the open‐circuit voltage (Voc ) regime of OPDs is shown to be efficient for detecting low light signals (<100 µW cm−2). It is established that the light‐dependence of Voc exhibits two distinct regimes as function of irradiance: linear and logarithmic. Whereas the observed logarithmic regime is well understood in organic photovoltaic cells (OPVs), it is shown experimentally and theoretically that the linear regime is due to the non‐infinite shunt resistance of the OPD device. Overall, OPDs composed of rubrene and fullerene show photovoltage light sensitivity across nine orders of magnitude with a detection limit as low as 400 pW cm−2. A photovoltage responsivity of 1.75 V m2 W−1 demonstrates highly efficient performance without the necessity to supress high dark current. This approach opens up new possibilities for resolving low light signals and provides simplified design rules for OPDs.

The distributed sense of touch forms an essential component that defines real-time perception and situational awareness in humans. Electronic skins are an emerging technology in conferring an artificial sense of touch for smart human–machine interfaces. However, assigning a conformably distributed sense of touch over a large area has been challenging to replicate in modern medical, social, and industrial robots. Herein, we present a new class of soft tactile sensors that exploit the mechanisms of triplet–triplet annihilation, exciton harvesting, and a small Stokes shift in conjugated organic semiconductors such as rubrene. By multiplexing the electroluminescence and photosensing modes, we show that a compact optoelectronic array of multifunctional rubrene/fullerene diodes can accurately measure pressure, position, and surface deformation applied to an overlying elastomeric layer. The dynamic range of sensing is defined by mechanical properties of the elastomer. Such optoelectronic approach paves the way for soft, conformal, and large-area compatible electronic skins for medicine and robotics.

Multifunctional operation of tetracene/polycyclopentadithiophene‐benzothiadiazole (PCPDTBT), and tetracene sensitized PCPDTBT:fullerene bulk heterojunctions (BHJs) that work as an organic photovoltaic (OPV), organic light emitting diode (OLED), and organic photodetector (OPD) is unveiled. The multifunctional operation is underlined by a synergetic interplay between singlet and triplet energy transfer and the judicious alignment of energy levels of donor–acceptor cascade. Introduction of tetracene is shown to enhance electroluminescence (EL) at 800 nm despite the observation of a near‐complete photoluminescence quenching in BHJ systems. Signatures of triple energy transfer mediated via charge transfer states of BHJ to tetracene become apparent as the proportion of fullerene in the BHJ is increased. An optimal balance between exciton population is achieved with BHJ 1:2 that produces EL peaks at 530 and 800 nm while maintaining a respectable OPV and OPD performance. The proposed ternary system unlocks the potential of having multifunctionality within one single diode structure, and it also offers new design rules for multispectral OLEDs.

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The fossil fuel is decreasing rapidly and excessive use of such fuels is also hazardous for the environment. Hence, renewable energy usage is the inevitable alternative to meet up electricity demand for the developing country like Bangladesh. Although solar technology has nearly been successful in rural areas where most of the technologies are adopted based on Solar Home System(SHS), it has not yet been effective in urban areas after the imposed rule of installing solar system to get new electricity connection from power utility for various reasons. In this paper, the investigation result of the installed solar system in an area in Dhaka is presented. The overall problems regarding the connection of the system components are analyzed. Efficiency calculation for the active solar home systems is provided through cost comparison analysis by HOMER software. Some proposals are provided which can be implemented to make the concept of solar home system popular in urban ares of Bangladesh to decrease the pressure on our national grid.

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