High‐Performance Circularly Polarized Light‐Sensing Near‐Infrared Organic Phototransistors for Optoelectronic Cryptographic Primitives

Abstract

Chiral photonics has emerged as a key technology for future optoelectronics, such as quantum information and encryption, by making use of photonic waves from enantiomeric structures. An inevitable challenge for realizing such chiral optoelectronics is the development of near-infrared circularly polarized (NIR CP) light-sensing photodetectors that convert optical power and circular polarization direction into distinguishable electrical signals. Herein, a simple and promising strategy for high-performance NIR CP light-sensing organic phototransistors (NIR CPL-OPTRs) applicable to highly secure optoelectronic encryption is proposed. By directly assembling a standalone cholesteric liquid-crystal network film in a thin-film NIR CPL-OPTR, remarkable responsivity and distinguishability are achieved. The synergetic effect of amplification of the photocurrent signal by the applied electric field and improved light absorption by the reduced reflection in the multilayered structure leads to high responsivity. As a proof-of-concept, the chiral phototransistor arrays are demonstrated as a physically unclonable function device and exhibit enhanced cryptographic characteristics.

Supramolecular engineering of charge transfer in wide bandgap organic semiconductors with enhanced visible-to-NIR photoresponse

“…20c shows the D* of the vertical phototransistors as a function of the incident irradiance. In the accumulated region, the calculated maximal D* can reach ≈1.2 × 10 13 Jones under an incident intensity of 0.4 μW/cm 2 , which is superior to some of the reported narrow bandgap organic-based NIR photodetectors [38][39][40][41] . When we extended the NIR light to 740 and 940 nm, the PTCDI-C8 nanowires VPTs have also validated excellent NIR light photoresponse, which are similar to the results obtained at 850 nm NIR light, as shown in Supplementary Figs.…”

Near‐Infrared Organic Phototransistors with p‐Channel Photosensitive Layers of Conjugated Polymer Composed of bis‐Octyldodecyl‐Diketopyrrolopyrrole and Benzothiadiazole Units

“…The resulting conjugated polymer, poly[{2,5-bis-(2-octyldodecyl)-3,6-bis-(thien-2yl)-pyrrolo [3,4-c]pyrrole-1,4-diyl}-co-{2,2′-(2,1,3-benzothiadiazole)-5,5′-diyl}] (PODTPPD-BT), exhibited strong optical absorptions in the NIR range. Note that the identical polymer has been reported for the OFETs using SiO 2 /Si substrates [41][42][43] but not applied for flexible NIR-OPTRs (the polymer in ref. [43] was initially synthesized in our group (by the first author in ref.…”

“…Note that the identical polymer has been reported for the OFETs using SiO 2 /Si substrates [41][42][43] but not applied for flexible NIR-OPTRs (the polymer in ref. [43] was initially synthesized in our group (by the first author in ref. [43]) and being applied for NIR-OPTRs (by the first author in this paper) but its application has been reported slightly earlier than this work).…”

“…[43] was initially synthesized in our group (by the first author in ref. [43]) and being applied for NIR-OPTRs (by the first author in this paper) but its application has been reported slightly earlier than this work). The device result showed that the PODTPPD-BT polymer could successfully act as a channel layer for a properly working OFET that was able to detect NIR light leading to a NIR-OPTR despite a limited photoresponsivity.…”

Circularly Polarized Photodetectors Based on Chiral Materials: A Review

“…More importantly, the predominant left-handed helical organization and the broad wavelength tunability of the photonic bandgap were harnessed for the detection of CPL, as shown in Figure 8B . This sentence has been modified to By introducing a cholesteric liquid crystal network films (CLCN) on the phototransistor based on small-bandgap conjugated polymer poly[{2,5-bis-(2-octyldodecyl)-3,6-bis-(thien-2-yl)pyrrolo[3,4-c]pyrrole-1,4-diyl}-co-{2,2′-(2,1,3-benzothiadiazole)]5,5′-diyl}] (PODTPPD-BT) as a reflector, Han et al Han et al (2020) reported a near-infrared circularly polarized light–sensing photodetector (NIR CPL-OPTR). Due to the ability of the CLC film to distinguish the polarization direction of CP light, the final NIR CPL-OPTR device achieved a dissymmetry factor of 1.9 ( Figure 8C ).…”