Organic Thin‐Film Transistors as Cannabinoid Sensors: Effect of Analytes on Phthalocyanine Film Crystallization

Abstract

With a growing international trend of Cannabis legalization, there is a present need for on-the-spot, low cost, and rapid detection of cannabinoids. Here, relationships between thin-films of phthalocyanines (Pcs) with a variety of central, peripheral, and axial substituents and their response to the cannabinoid Δ 9 -tetrahydrocannabinol (THC), with and without a cannabinoid-sensitive chromophore (Fast Blue BB) are investigated through organic thin-film transistor (OTFT) performance. X-ray diffraction and UV-vis absorption spectroscopy measurements demonstrate significantly altered film morphologies and the formation of new crystal orientations in response to analytes, which are corroborated by scanning electron microscopy. Electron paramagnetic resonance further corroborates shifting crystal structures in response to THC and also reveals the formation and promotion of Pc radical species through THC-metal coordination. With exposure to THC, aluminum chloride Pc generates the largest physical film changes as well as the largest changes in OTFT performance. These findings suggest that the semiconductor thin-film morphologies in Pc-based OTFT sensors are not static in the presence of analytes and that the sensing response is driven both by strong analyte-Pc coordination and bulk film restructuring to accommodate these interactions.

Chloro aluminum phthalocyanine-based organic thin-film transistors as cannabinoid sensors: engineering the thin film response

“…23,24 MPcs are thermally and chemically stable, inexpensive to manufacture on the ton scale with facile metal substitution providing opportunities to tune molecular interactions for integration into OTFT sensors. 6,21,[25][26][27][28][29][30] While many MPcs are insoluble 2 or sparingly soluble in organic solvents, they can be modified with solubilizing groups making them potentially compatible with low-cost solution processing techniques. Previously, we demonstrated copper phthalocyanine (CuPc) OTFT sensors for ratiometric detection and differentiation of cannabinoids.…”

“…31 These interactions can induce recrystallization of MPc thin-films, altering thin-film morphologies and nanostructures, resulting in OTFT performance changes which enhance the detection of THC and lead to better sensitivity. 26 The central aluminum chloride of chloro aluminum phthalocyanine (Cl-AlPc, Figure 1) bends the MPc ring, resulting in unique packing structures that are susceptible to cannabinoid induced physical effects, demonstrating greater interactions both in solution and as a thin-film compared to CuPc. 26,31 In bottom-gate bottom-contact (BGBC) OTFTs, the thickness of the deposited semiconductor film has been observed to effect OTFT charge transport properties.…”

“…26 The central aluminum chloride of chloro aluminum phthalocyanine (Cl-AlPc, Figure 1) bends the MPc ring, resulting in unique packing structures that are susceptible to cannabinoid induced physical effects, demonstrating greater interactions both in solution and as a thin-film compared to CuPc. 26,31 In bottom-gate bottom-contact (BGBC) OTFTs, the thickness of the deposited semiconductor film has been observed to effect OTFT charge transport properties. [32][33][34] For evaporated small molecules, surface coverage, growth mode, and thin-film morphology can change with thickness, leading to altered charge transport properties.…”

Building a Versatile Platform for the Detection of Protein–Protein Interactions Based on Organic Field-Effect Transistors

“…, multiple detection pathways). − They can also be manufactured through large-scale solution deposition techniques, including roll-to-roll and inkjet printing . Due to these advantages, TFTs have been explored as gas sensors and for the detection of other types of analytes, including cannabinoids and chemical warfare agents. − …”

Constructing two-dimensional crossed molecular packing through branching chain engineering of amino-indenofluorene derivatives

“…Organic thin-film transistors (OTFTs) are key components of organic electronics and have received great attention in the last two decades [1][2][3] and have wide applications in various electronic devices, such as flexible displays, [4][5][6][7] electronic skins, [8][9][10][11] memory, [12][13][14] logic circuits, [15][16][17] and sensors. [18][19][20] One attractive feature of OTFTs is that they can be solution processed, making large scale manufacturing and fabrication on flexible substrate feasible.…”