Anomalous Transient Photocurrent

Utilizing Photocurrent Transients for Dithiolene-Based Photodetection: Stepwise Improvements at Communications Relevant Wavelengths

“…In this instance, the bulk region of BDN can be thought of as acting as a capacitor, which charges up upon light-on, and discharges upon light-off. 22 With this in mind, improvements in photocurrent response could be envisioned by replacing the bulk region of BDN with a more suitable dielectric, forming a metal/semiconductor/insulator/metal architecture. We have previously studied the effect of different dielectric layers on the size of photocurrent transient in an MSIM photocell with a zinc phthalocyanine (ZnPc):C 60 active layer.…”

“…The size of this “pseudo-steady-state” response would therefore be determined by how much charge had managed to redistribute upon light off after the previous light pulse. In this instance, the bulk region of BDN can be thought of as acting as a capacitor, which charges up upon light-on, and discharges upon light-off . With this in mind, improvements in photocurrent response could be envisioned by replacing the bulk region of BDN with a more suitable dielectric, forming a metal/semiconductor/insulator/metal architecture.…”

“…We have previously studied the effect of different dielectric layers on the size of photocurrent transient in an MSIM photocell with a zinc phthalocyanine (ZnPc):C 60 active layer. , From this study, it is clear that an ideal dielectric would have high capacitance, and a high dielectric constant, since the former would decrease the dark current, improving the detectivity of the photoresponse, and the latter would facilitate improved charge separation in the film. To this end, polyvinylidene fluoride (PVDF), an organic insulating polymer with high dielectric constant (ε = 7–13), was investigated.…”

“…A recent development in the field of organic optoelectronics is the incorporation of dielectric materials into devices either as blended components , or as distinct layers. , While organic semiconductors generally show high exciton binding energies that limit charge separation/extraction, and pose design restrictions on photovoltaic devices, organic materials are inherently more polarizable than inorganic materials, and the local electric fields generated by the dielectrics can aid charge separation/extraction, leading to improvements in LEC for organic optoelectronic devices. , For devices such as photodetectors, dielectric materials offer an additional benefit by decreasing the dark current that flows through the device, thus increasing its detectivity if the light-on current can be maintained.…”