Sulfur- and Nitrogen-Containing Porous Donor-Acceptor Polymers as Real-Time Optical and Chemical Sensors

Abstract

Fully aromatic, organic polymers have the advantage of being composed from light, abundant elements, and are hailed as candidates in electronic and optical devices “beyond silicon”, yet, applications that make use of their π-conjugated backbone and optical bandgap are lacking outside of heterogeneous catalysis. Herein, we use a series of sulfur- and nitrogen-containing porous polymers (SNPs) as real-time optical and electronic sensors reversibly triggered and re-set by acid and ammonia vapors. Our SNPs incorporate donor-acceptor and donor-donor motifs in extended networks and enable us to study the changes in bulk conductivity, optical bandgap, and fluorescence life-times as a function of π-electron de-/localization in the pristine and protonated states. Interestingly, we find that protonated donor-acceptor polymers show a decrease of the optical bandgap by 0.42 eV to 0.76 eV and longer fluorescence life-times. In contrast, protonation of a donor-donor polymer does not affect its bandgap; however, it leads to an increase of electrical conductivity by up to 25-fold and shorter fluorescence life-times. The design strategies highlighted in this study open new avenues towards useful chemical switches and sensors based on modular purely organic materials.

Donor-Acceptor Polymer Networks from Triarylborane and Thiophene Building Blocks for Photocatalytic Hydrogen Evolution from Aqueous Solution

“…Testing of multiple batches as well as multiple runs on the same batch confirmed the activity of the best-performing material, TT-TAB, within a 15% error margin, as is typically observed for batchbased photocatalytic hydrogen evolution testing (Figure S14). [30] Application of the same conditions to our previously reported sulfur-and-nitrogen-based polymer networks (SNPs) [2,16] showed that for these materials, triethanolamine and triethylamine afford higher activities than L-ascorbic acid (Figure S12). This behaviour seems at first surprising given that acidic media tends to favor proton reduction by enhancing donor-acceptor interactions between protonated triazines and sulfur-containing donors in SNPs.…”

“…[2,5,[9][10][11][12] Aromatic amines can be used to incorporate the larger heptazine (C6N7) core via nucleophilic substitution to yield N-bridged donoracceptor systems, [13][14][15] but only the triazine core has been directly cross-coupled via carbon-carbon bond formation to yield highly photoactive materials. [2,16] Recently, sulfone oxides were introduced as electron acceptors for hydrogen evolution photocatalysts. The sulfone oxides serve dual functions as electron acceptors while improving the wettability of the aromatic polymer backbone for enhanced catalyst-substrate interaction.…”

An Optical Chiral Sensor Based on Weak Measurement for the Real-Time Monitoring of Sucrose Hydrolysis

“…Optical technology shows distinct superiority in real-time sensing in numerous applications, such as chemical sensing and biosensing [ 10 , 11 , 12 ]. Especially, optical sensors based on surface plasmon resonance (SPR) have played a non-negligible role in the area of chemical sensing, foodborne marker screening, environmental monitoring and medical diagnostics [ 13 ].…”

Optical, morphological and photocatalytic properties of biobased tractable films of chitosan/donor-acceptor polymer blends

“…Over the last decades, donor and acceptor polymers (D-APs) have been extensively studied due to their wide range of potential applications in organic solar cells (Facchetti, 2013), light emitting diodes (Thompson et al, 2005), sensors (Kochergin et al, 2019), energy conversion (Gao et al, 2016), and storage devices (Guo, Li, Yu, Perepichka, & Meng, 2017). Thus, many synthetic strategies, mainly based on chemical modification, have been developed with the aim to diversify the properties and to achieve a higher versatility for this type of materials (Davis et al, 2017;Deng & Doyle, 2016;Wu et al, 2017).…”