Printed organic photodetectors can transform plastic, paper or glass into smart surfaces. This innovative technology is now growing exponentially due to the strong demand in human-machine interfaces. To date, only niche markets are targeted since organic sensors still present reduced performances in comparison with their inorganic counterparts. Here we demonstrate that it is possible to engineer a state-of-the-art organic photodetector approaching the performances of Si-based photodiodes in terms of dark current, responsivity and detectivity. Only three solution-processed layers and two low-temperature annealing steps are needed to achieve the performance that is significantly better than most of the organic photodetectors reported so far. We also perform a long-term ageing study. Lifetimes of over 14,000 hours under continuous operation are more than promising and demonstrate that organic photodetectors can reach a competitive level of stability for successful commercialization of this new and promising technology.
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.
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