@article{yang_riley_rodenhausen_skoog_stafslien_vanderwal_narayan_2022, title={Antifungal behavior of silicon-incorporated diamond-like carbon by tuning surface hydrophobicity with plasma treatment}, ISSN={["1744-7402"]}, DOI={10.1111/ijac.14048}, abstractNote={Silicon-incorporated diamond-like carbon (Si-DLC), an amorphous material containing Si atoms with sp3- and sp2-hybridized carbon, is a promising biomaterial for versatile biomedical applications due to its excellent mechanical properties, chemical inertness, biocompatibility, and antimicrobial capability. However, the antifungal properties of plasma-treated Si-DLC have not been systematically evaluated. In this study, Si-DLC coatings were deposited by chemical vapor deposition and further treated with either oxygen or fluorine plasma to render the surface anchored with different functional groups and hydrophobicity. Surface roughness was probed with atomic force microscopy, whereas bonding character and surface composition were assessed using Raman and X-ray photoelectron spectroscopy. Wettability and surface charge were investigated via water contact angle and zeta potential measurements. Antifungal assessment was performed using a Candida albicans multi-well plate screening technique and crystal violet biomass quantification. The results demonstrate that oxygen plasma–treated Si-DLC exhibited hydrophilic properties, lower negative zeta potential, and significant antifungal behavior. This material can potentially be applied on surfaces for the prevention of reduced nosocomial infections.}, journal={INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY}, author={Yang, Kai-Hung and Riley, Parand and Rodenhausen, Keith B. and Skoog, Shelby A. and Stafslien, Shane J. and Vanderwal, Lyndsi and Narayan, Roger J.}, year={2022}, month={May} }
 @article{joshi_shukla_gupta_riley_narayan_narayan_2022, title={Excimer Laser Patterned Holey Graphene Oxide Films for Nonenzymatic Electrochemical Sensing}, volume={14}, ISSN={["1944-8252"]}, url={https://doi.org/10.1021/acsami.2c09096}, DOI={10.1021/acsami.2c09096}, abstractNote={The existence of point defects, holes, and corrugations (macroscopic defects) induces high catalytic potential in graphene and its derivatives. We report a systematic approach for microscopic and macroscopic defect density optimization in excimer laser-induced reduced graphene oxide by varying the laser energy density and pulse number to achieve a record detection limit of 7.15 nM for peroxide sensing. A quantitative estimation of point defect densities was obtained using Raman spectroscopy and confirmed with electrochemical sensing measurements. Laser annealing (LA) at 0.6 J cm-2 led to the formation of highly reduced graphene oxide (GO) by liquid-phase regrowth of molten carbon with the presence of dangling bonds, making it catalytically active. Hall-effect measurements yielded a mobility of ∼200 cm2 V-1 s-1. An additional increase in the number of pulses at 0.6 J cm-2 resulted in deoxygenation through the solid-state route, leading to the formation of holey graphene structure. The average hole size showed a hierarchical increase, with the number of pulses characterized with multiple microscopy techniques, including scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The exposure of edge sites due to high hole density after 10 pulses supported the formation of proximal diffusion layers, which led to facile mass transfer and improvement in the detection limit from 25.4 mM to 7.15 nM for peroxide sensing. However, LA at 1 J cm-2 with 1 pulse resulted in a high melt lifetime of molten carbon and the formation of GO characterized by a high resistivity of 3 × 10-2 Ω-cm, which was not ideal for sensing applications. The rapid thermal annealing technique using a batch furnace to generate holey graphene results in structure with uneven hole sizes. However, holey graphene formation using the LA technique is scalable with better control over hole size and density. This study will pave the path for cost-efficient and high-performance holey graphene sensors for advanced sensing applications.}, number={32}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Joshi, Pratik and Shukla, Shubhangi and Gupta, Siddharth and Riley, Parand R. and Narayan, Jagdish and Narayan, Roger}, year={2022}, month={Aug}, pages={37149–37160} }
 @article{riley_joshi_khosla_narayan_narayan_2022, title={Formation of Q-carbon with wafer scale integration}, volume={196}, ISSN={["1873-3891"]}, url={https://doi.org/10.1016/j.carbon.2022.06.003}, DOI={10.1016/j.carbon.2022.06.003}, abstractNote={We describe the formation of highly uniform Quenched-carbon (Q-carbon) layers by plasma-enhanced chemical vapor deposition (PECVD) followed by low-energy Ar+ ion bombardment to achieve wafer-scale integration of Q-carbon films. After PECVD, 9 nm and 20 nm thick silicon-doped diamond-like carbon (Si-DLC) films showed complete conversion into Q-carbon using 250eV Ar+ ions via negative biasing. However, this conversion was only partial for 30 nm thick films. Detailed EELS, XPS, Raman, and EDS studies were carried out to confirm the formation of Q-carbon by this method. We discuss the mechanism of Q-carbon formation as a result of low-energy ion bombardment during PECVD of thin films. These ions during negative biasing are energetic enough to create Frenkel defects, which support the conversion of the three-fold coordinated sp2 carbon units in as-deposited carbon into sp3 bonded five-atom tetrahedron units in Q-carbon. This process enhances the atomic number density and fraction of sp3 bonded carbon. These diamond tetrahedra are randomly packed and provide easy nucleation sites for diamond. If the underlying substrate can provide an epitaxial template for diamond growth via domain matching epitaxy, then wafer-scale growth of diamond epitaxial films can be achieved for wafer-scale integration and next-generation novel device manufacturing from diamond-related materials.}, journal={CARBON}, author={Riley, Parand R. and Joshi, Pratik and Khosla, Nayna and Narayan, Roger J. and Narayan, Jagdish}, year={2022}, month={Aug}, pages={972–978} }
 @article{joshi_riley_denning_shukla_khosla_narayan_narayan_2022, title={Laser-patterned carbon coatings on flexible and optically transparent plastic substrates for advanced biomedical sensing and implant applications}, volume={1}, ISSN={["2050-7534"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85125716163&partnerID=MN8TOARS}, DOI={10.1039/d1tc05176h}, abstractNote={Plasma and laser-based processing for tailoring DLC thin film properties for state-of-the-art wearable sensing applications.}, number={8}, journal={JOURNAL OF MATERIALS CHEMISTRY C}, publisher={Royal Society of Chemistry (RSC)}, author={Joshi, Pratik and Riley, Parand R. and Denning, Warren and Shukla, Shubhangi and Khosla, Nayna and Narayan, Jagdish and Narayan, Roger}, year={2022}, month={Jan} }
 @misc{joshi_riley_goud_mishra_narayan_2022, title={Recent advances of boron-doped diamond electrochemical sensors toward environmental applications}, volume={32}, ISSN={["2451-9103"]}, DOI={10.1016/j.coelec.2021.100920}, abstractNote={The electrocatalytic properties of boron-doped diamond (BDD) electrodes have been considered for a variety of sensing applications. The unusual electrochemical properties of BDD include a large potential window, a small background current, and better resistance to fouling than other carbon-based electrodes. The use of BDD for remediation and environmental sensing applications has recently attracted the interest of the sensor research community. This review focuses on recent developments that involve the use of BDD as an environmentally friendly sensing material for environmental analysis. The electrochemical properties of boron-doped diamond that has undergone surface modification (e.g., with metals or enzymes) will be considered. Recent achievements involving the use of BDD electrodes for detecting pesticides, mycotoxins, peroxides, and phenolic compounds are considered.}, journal={CURRENT OPINION IN ELECTROCHEMISTRY}, author={Joshi, Pratik and Riley, Parand and Goud, K. Yugender and Mishra, Rupesh K. and Narayan, Roger}, year={2022}, month={Apr} }
 @article{shukla_joshi_riley_narayan_2022, title={Square wave voltammetric approach to leptin immunosensing and optimization of driving parameters with chemometrics}, volume={216}, ISSN={["1873-4235"]}, DOI={10.1016/j.bios.2022.114592}, abstractNote={Square wave voltammetry serves as an effective analytical means to evaluate antigen-antibody coupling at the solid-liquid interface. Herein, we describe 3-aminopropyltrimethoxysilane (APTMS) induced irreversible immobilization of anti-leptin to micellar gold nanoparticles (AuNPs). Antibodies (Abs) were orthogonally loaded on micellized AuNP assemblies via amino residual groups. The ratio of bound Ab molecules was determined by the Bradford assay. The AuNP/Ab layer modified electrodes with variable antibody surface coverage (∼400 ± 55–200 ± 30 Ab/NP) were analyzed in terms of change in backward, net current (Ip) components. The rate of antigen coupling was found to be consistent with the variation in antibody density as well as the binding affinity. The lowest detection limit was observed at the femtomolar level (0.25 fM/mL) over a wide range of antigen concentration (6.2 ng/mL to 0.12 fg/mL). The variables affecting the epitope-paratope interaction were further optimized using a chemometric approach and a response surface methodology (RSM).}, journal={BIOSENSORS & BIOELECTRONICS}, author={Shukla, Shubhangi and Joshi, Pratik and Riley, Parand and Narayan, Roger J.}, year={2022}, month={Nov} }
 @article{joshi_riley_mishra_machekposhti_narayan_2022, title={Transdermal Polymeric Microneedle Sensing Platform for Fentanyl Detection in Biofluid}, volume={12}, ISSN={["2079-6374"]}, DOI={10.3390/bios12040198}, abstractNote={Opioid drugs are extremely potent synthetic analytes, and their abuse is common around the world. Hence, a rapid and point-of-need device is necessary to assess the presence of this compound in body fluid so that a timely countermeasure can be provided to the exposed individuals. Herein, we present an attractive microneedle sensing platform for the detection of the opioid drug fentanyl in real serum samples using an electrochemical detection method. The device contained an array of pyramidal microneedle structures that were integrated with platinum (Pt) and silver (Ag) wires, each with a microcavity opening. The working sensor was modified by graphene ink and subsequently with 4 (3-Butyl-1-imidazolio)-1-butanesulfonate) ionic liquid. The microneedle sensor showed direct oxidation of fentanyl in liquid samples with a detection limit of 27.8 μM by employing a highly sensitive square-wave voltammetry technique. The resulting microneedle-based sensing platform displayed an interference-free fentanyl detection in diluted serum without conceding its sensitivity, stability, and response time. The obtained results revealed that the microneedle sensor holds considerable promise for point-of-need fentanyl detection and opens additional opportunities for detecting substances of abuse in emergencies.}, number={4}, journal={BIOSENSORS-BASEL}, author={Joshi, Pratik and Riley, Parand R. and Mishra, Rupesh and Machekposhti, Sina Azizi and Narayan, Roger}, year={2022}, month={Apr} }
 @misc{joshi_riley_gupta_narayan_narayan_2021, title={Advances in laser-assisted conversion of polymeric and graphitic carbon into nanodiamond films}, volume={32}, ISSN={["1361-6528"]}, url={https://doi.org/10.1088/1361-6528/ac1097}, DOI={10.1088/1361-6528/ac1097}, abstractNote={Nanodiamond (ND) synthesis by nanosecond laser irradiation has sparked tremendous scientific and technological interest. This review describes efforts to obtain cost-effective ND synthesis from polymers and carbon nanotubes (CNT) by the melting route. For polymers, ultraviolet (UV) irradiation triggers intricate photothermal and photochemical processes that result in photochemical degradation, subsequently generating an amorphous carbon film; this process is followed by melting and undercooling of the carbon film at rates exceeding 109 K s−1. Multiple laser shots increase the absorption coefficient of PTFE, resulting in the growth of 〈110〉 oriented ND film. Multiple laser shots on CNTs result in pseudo topotactic diamond growth to form a diamond fiber. This technique is useful for fabricating 4–50 nm sized NDs. These NDs can further be employed as seed materials that are used in bulk epitaxial growth of microdiamonds using chemical vapor deposition, particularly for use with non-lattice matched substrates that formerly did not form continuous and adherent films. We also provide insights into biocompatible precursors for ND synthesis such as polybenzimidazole fiber. ND fabrication by UV irradiation of graphitic and polymeric carbon opens up a pathway for preparing selective coatings of polymer-diamond composites, doped nanodiamonds, and graphene composites for quantum computing and biomedical applications.}, number={43}, journal={NANOTECHNOLOGY}, publisher={IOP Publishing}, author={Joshi, Pratik and Riley, Parand and Gupta, Siddharth and Narayan, Roger J. and Narayan, Jagdish}, year={2021}, month={Oct} }
 @article{riley_joshi_azizi machekposhti_sachan_narayan_narayan_2021, title={Enhanced Vapor Transmission Barrier Properties via Silicon-Incorporated Diamond-Like Carbon Coating}, volume={13}, ISSN={["2073-4360"]}, DOI={10.3390/polym13203543}, abstractNote={In this study, we describe reducing the moisture vapor transmission through a commercial polymer bag material using a silicon-incorporated diamond-like carbon (Si-DLC) coating that was deposited using plasma-enhanced chemical vapor deposition. The structure of the Si-DLC coating was analyzed using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and electron energy loss spectroscopy. Moisture vapor transmission rate (MVTR) testing was used to understand the moisture transmission barrier properties of Si-DLC-coated polymer bag material; the MVTR values decreased from 10.10 g/m2 24 h for the as-received polymer bag material to 6.31 g/m2 24 h for the Si-DLC-coated polymer bag material. Water stability tests were conducted to understand the resistance of the Si-DLC coatings toward moisture; the results confirmed the stability of Si-DLC coatings in contact with water up to 100 °C for 4 h. A peel-off adhesion test using scotch tape indicated that the good adhesion of the Si-DLC film to the substrate was preserved in contact with water up to 100 °C for 4 h.}, number={20}, journal={POLYMERS}, author={Riley, Parand R. and Joshi, Pratik and Azizi Machekposhti, Sina and Sachan, Ritesh and Narayan, Jagdish and Narayan, Roger J.}, year={2021}, month={Oct} }
 @article{riley_joshi_narayan_narayan_2021, title={Enhanced nucleation and large-scale growth of CVD diamond via surface-modification of silicon-incorporated diamond-like carbon thin films}, volume={120}, ISSN={["1879-0062"]}, DOI={10.1016/j.diamond.2021.108630}, abstractNote={Herein we report a method to tailor the surface of silicon-incorporated diamond-like carbon (Si-DLC) thin films to enhance the diamond nucleation density and growth. In this technique, the surfaces of Si-DLC films were modified by fluorine and oxygen species utilizing a reactive-ion etching (RIE) method. The surface properties of Si-DLC, oxygen-terminated Si-DLC (O Si-DLC), and fluorine-terminated Si-DLC (F Si-DLC) films were investigated and compared. The analyses depicted that the sp2/sp3 ratio of carbon‑carbon bonds has diminished from 20.28% for Si-DLC film down to 8.96% and 4.41% for O Si-DLC and F Si-DLC films, respectively. Moreover, a significant amount of new sp3 hybridized bonds formed on the surface of the modified Si-DLC thin films, particularly in F Si-DLC film. The deposition of micro-diamond on the films was performed using hot filament chemical vapor deposition (HFCVD). SEM, XRD, and Raman results showed the enhancement in nucleation density and growth of micro-diamond on F Si-DLC and O Si-DLC films and the in-plane stress reduction up to 60%. Owing to the lower number of sp2 bonds and the greater number of new sp3 sites, the F Si-DLC thin film provided a superior platform for diamond nucleation than O Si-DLC film. The continuous diamond coverage on F Si-DLC film was up to ~2 mm2 versus ~0.4 mm2 for O Si-DLC film.}, journal={DIAMOND AND RELATED MATERIALS}, author={Riley, Parand R. and Joshi, Pratik and Narayan, Jagdish and Narayan, Roger J.}, year={2021}, month={Dec} }
 @article{narayan_bhaumik_gupta_joshi_riley_narayan_2021, title={Formation of self-organized nano- and micro-diamond rings}, volume={9}, ISSN={["2166-3831"]}, DOI={10.1080/21663831.2021.1907627}, abstractNote={We report formation of self-organized nanodiamond ring structures due to dynamical heterogeneity in super undercooled carbon, created by nanosecond laser melting of amorphous carbon layers. We envisage that diamond tetrahedra self-organize and lead to formation of string and ring structures on which nanodiamonds nucleate and grow. Denser ring structures are formed in Q-carbon due to higher undercooling and enhanced diamond nucleation. The average size is larger under heterogeneous nucleation compared to homogeneous nucleation due to lower critical size and free energy, allowing more time for growth. With nanosecond laser melting, growth velocities range 5–10 ms−1 and even higher for Q-carbon. GRAPHICAL ABSTRACT IMPACT STATEMENT Significant advancement in the creation of self-organized nanodiamond ring and string structures by laser processing at ambient pressure and temperature}, number={7}, journal={MATERIALS RESEARCH LETTERS}, author={Narayan, J. and Bhaumik, A. and Gupta, S. and Joshi, P. and Riley, P. and Narayan, R. J.}, year={2021}, month={Mar}, pages={300–307} }
 @article{joshi_gupta_riley_narayan_narayan_2021, title={Liquid phase regrowth of (110) nanodiamond film by UV laser annealing of PTFE to generate dense CVD microdiamond film}, volume={117}, ISSN={["1879-0062"]}, DOI={10.1016/j.diamond.2021.108481}, abstractNote={Herein we report the conversion of polytetrafluoroethylene (PTFE) into 〈110〉 nanodiamonds via a melting route using pulsed laser annealing (PLA). The converted nanodiamond (ND) film is used as a seed layer to grow dense microdiamond coating synthesized by chemical vapor deposition. We utilize an ArF excimer laser with a photon energy of 6.4 eV to decompose PTFE (bandgap: 6.0 eV). Initial laser pulses result in photochemical decomposition of PTFE, and PTFE is converted to an amorphous carbon film. This amorphous carbon film, when subjected to additional laser pulses melts, and when this melt is quenched from an undercooled state at rates exceeding 109 K/s, it undergoes first-order phase transformation into the ND film. Notably, the obtained NDs are phase pure, exhibiting full width at half maxima (FWHM) of 1.23 cm−1 and demonstrating 〈110〉 out of plane orientation characterized by Raman spectroscopy and transmission electron microscopy, respectively. The average ND size is ~28.5 nm (range: 5-30 nm) determined by scanning electron microscopy and X-ray diffraction. The COMSOL simulations substantiate the use of nanosecond laser pulses with an energy density in the range of 0.6–0.8 J/cm2 to fully convert ~ 50% crystalline PTFE into ND film. The CVD microdiamonds grew densely on the ND seed layer as compared to reduced graphene oxide confirmed by SEM and Raman analysis. This innovative method of ND fabrication by UV irradiation of PTFE opens up opportunities for generating selective coatings of advanced polymer-diamond composites and doped nanodiamonds for quantum computing and biomedical applications.}, journal={DIAMOND AND RELATED MATERIALS}, author={Joshi, Pratik and Gupta, Siddharth and Riley, Parand R. and Narayan, Roger J. and Narayan, Jagdish}, year={2021}, month={Aug} }
 @article{riley_joshi_penchev_narayan_narayan_2021, title={One-Step Formation of Reduced Graphene Oxide from Insulating Polymers Induced by Laser Writing Method}, volume={11}, ISSN={["2073-4352"]}, DOI={10.3390/cryst11111308}, abstractNote={Finding a low-cost and effective method at low temperatures for producing reduced graphene oxide (rGO) has been the focus of many efforts in the research community for almost two decades. Overall, rGO is a promising candidate for use in supercapacitors, batteries, biosensors, photovoltaic devices, corrosion inhibitors, and optical devices. Herein, we report the formation of rGO from two electrically insulating polymers, polytetrafluoroethylene (PTFE) and meta-polybenzimidazole fiber (m-PBI), using an excimer pulsed laser annealing (PLA) method. The results from X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy confirm the successful generation of rGO with the formation of a multilayered structure. We investigated the mechanisms for the transformation of PTFE and PBI into rGO. The PTFE transition occurs by both a photochemical mechanism and a photothermal mechanism. The transition of PBI is dominated by a photo-oxidation mechanism and stepwise thermal degradation. After degradation and degassing procedures, both the polymers leave behind free molten carbon with some oxygen and hydrogen content. The free molten carbon undergoes an undercooling process with a regrowth velocity (<4 m·s−1) that is necessary for the formation of rGO structures. This approach has the potential for use in creating future selective polymer-written electronics.}, number={11}, journal={CRYSTALS}, author={Riley, Parand R. and Joshi, Pratik and Penchev, Hristo and Narayan, Jagdish and Narayan, Roger J.}, year={2021}, month={Nov} }
 @misc{riley_narayan_2021, title={Recent advances in carbon nanomaterials for biomedical applications: A review}, volume={17}, ISSN={["2468-4511"]}, DOI={10.1016/j.cobme.2021.100262}, abstractNote={With the emergence of new pathogens like coronavirus disease 2019 and the prevalence of cancer as one of the leading causes of mortality globally, the effort to develop appropriate materials to address these challenges is a critical research area. Researchers around the world are investigating new types of materials and biological systems to fight against various diseases that affect humans and animals. Carbon nanostructures with their properties of straightforward functionalization, capability for drug loading, biocompatibility, and antiviral properties have become a major focus of biomedical researchers. However, reducing toxicity, enhancing biocompatibility, improving dispersibility, and enhancing water solubility have been challenging for carbon-based biomedical systems. The goal of this article is to provide a review on the latest progress involving the use of carbon nanostructures, namely fullerenes, graphene, and carbon nanotubes, for drug delivery, cancer therapy, and antiviral applications.}, journal={CURRENT OPINION IN BIOMEDICAL ENGINEERING}, author={Riley, Parand R. and Narayan, Roger J.}, year={2021}, month={Mar} }
 @article{narayan_bhaumik_gupta_joshi_riley_narayan_2021, title={Role of Q-carbon in nucleation and formation of continuous diamond film}, volume={176}, ISSN={["1873-3891"]}, DOI={10.1016/j.carbon.2021.02.049}, abstractNote={Formation of continuous and adherent diamond films on practical substrates presents a formidable challenge due to lack of diamond nucleation sites needed for diamond growth. This problem has been solved through the formation of interfacial Q-carbon layers by nanosecond laser melting of carbon layers in a highly undercooled state and subsequent quenching. The Q-carbon layer provides ready nucleation sites for epitaxial films on planar matching substrates such as sapphire, and polycrystalline films on amorphous substrates such as glass. Each laser pulse converts about a one-cm-square area, which can be repeated with a 100–200 Hz laser to produce potentially 100–200 cm2s-1 of diamond films. This is essentially a low-temperature processing, where substrate stays close to ambient temperature, because the total heat input is quite small. The Q-carbon layer is also responsible for improved adhesion of diamond films on sapphire and glass substrates. It is also argued that the formation of Q-carbon layer is also responsible for efficient diamond nucleation during negatively biased MPCVD diamond depositions.}, journal={CARBON}, author={Narayan, J. and Bhaumik, A. and Gupta, S. and Joshi, P. and Riley, P. and Narayan, R. J.}, year={2021}, month={May}, pages={558–568} }
 @article{jones_zheng_riley_pelse_zhang_abdelsamie_toney_marder_so_bredas_et al._2019, title={Acceptor Gradient Polymer Donors for Non-Fullerene Organic Solar Cells}, volume={31}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.9b03327}, abstractNote={In organic solar cells, maximizing the open-circuit voltage (VOC) via minimization of the ionization energy or electron affinity offsets of the blended donor and acceptor often comes at the expense...}, number={23}, journal={CHEMISTRY OF MATERIALS}, author={Jones, Austin L. and Zheng, Zilong and Riley, Parand and Pelse, Ian and Zhang, Junxiang and Abdelsamie, Maged and Toney, Michael F. and Marder, Seth R. and So, Franky and Bredas, Jean-Luc and et al.}, year={2019}, month={Dec}, pages={9729–9741} }
 @article{luo_tran_kadlubowski_ho_riley_so_mei_2018, title={Side-Chain Sequence Enabled Regioisomeric Acceptors for Conjugated Polymers}, volume={51}, ISSN={["1520-5835"]}, url={https://doi.org/10.1021/acs.macromol.8b01946}, DOI={10.1021/acs.macromol.8b01946}, abstractNote={Side-chain sequence enabled regioisomeric acceptors, bearing different side-chain sequences on the same conjugated backbone, are herein reported. Two regioregular polymers PTBI-1 and PTBI-2 and one regiorandom polymer PTBI-3 were synthesized from these two regioisomeric acceptors for a comparative study. UV–vis–NIR absorption spectroscopy and electrochemical study confirmed similar frontier molecular orbital levels of the three polymers in their solid state. More intriguingly, absorption profiles suggest that the sequence of side chains greatly governs the aggregation behaviors. Furthermore, the PTBI-2 film shows larger ordered domains than PTBI-1 and PTBI-3 films, as supported by AFM and GIWAXS measurements. As a result, PTBI-2-based FET devices achieved an average hole mobility of 1.37 cm2 V–1 s–1, much higher than the two polymers with other side-chain sequences. The regiorandom PTBI-3 exhibited the lowest average hole mobility of 0.27 cm2 V–1 s–1. This study highlights the significant impact of side-c...}, number={21}, journal={MACROMOLECULES}, publisher={American Chemical Society (ACS)}, author={Luo, Xuyi and Tran, Dung T. and Kadlubowski, Natalie M. and Ho, Carr Hoi Yi and Riley, Parand and So, Franky and Mei, Jianguo}, year={2018}, month={Nov}, pages={8486–8492} }