Fabrication and photoresponse characteristics of high rectification photodetector based on methyl violet nanoparticles-PVA/p-si heterojunction for optoelectronic applications

Photoresponse of an off-stoichiometry thiol–ene–epoxy (OSTE+) polymer

“…Therefore, these parameters were calculated using the metal–polymer–metal Schottky diode model with the help of eqn (5) and (6). For this calculation, the effective Richardson's constant ( A *) was taken as 2.4 × 10 −3 A cm −2 K −2 from the polyvinyl polymer (PVA) 25 based photodetector.where S is the junction area, T is the temperature, k is the Boltzmann constant, I 0 is the dark current, and q is the elementary charge.…”

“…Similar light illuminating on-off cycles have been observed in many conjugated semiconducting polymer devices that have been attributed to photoresponsive properties of these polymeric materials. 11,12,25…”

“…Further, the rising edge was observed as a single exponential behavior and the average rising time (interval of response to rise of current from 10 to 90% of the steady value) was found to be τ r = 0.61 ± 0.04 s. A similar behavior in photocurrent rising dynamics was observed for other semiconducting polymer photodetectors. 23,25,57…”

“…This kind of rectification has been observed in many polymer-metal junctions that define the electric field-assisted carrier conduction mechanism in various semiconducting polymer devices. 13,23,25 Actually, the ideal OSTE + device is supposed to be ambipolar in nature, but due to asymmetric fabrication, the device is having more reverse bias characteristics. The I-V characteristics of this device appeared to be unipolar at ambient temperature, due to the small potential difference at the two interfaces that decides the direction of current and hence the forward and reverse polarity of this device.…”

“…Also, various novel devices have been fabricated using these composites such as photodetectors, [11][12][13] organic field-effect transistors, 5,7,14 organic light-emitting diodes, 15,16 optical biosensors, 17,18 supercapacitors 19,20 and many more. In this regard, the conjugated semiconducting polymers such as poly (3-hexyl thiophene) (P3-HT), 21,22 polystyrene sulfonate (PEDOT: PSS) 14,23,24 and polyvinyl alcohol (PVA) 11,12,25 have been identified as primary materials for optoelectronic microdevice applications. In addition, several smart polymeric composites have also been prepared by blending these conducting polymers with biocompatible functional co-polymers for tuning the electronic conductivity, 26,27 mechanical flexibility, 28,29 and thermal stability 7,30 in thin-film structures.…”