@article{thorley_dremann_iqbal_parkin_jurchescu_anthony_2022, title={Crystal engineering of alkylethynyl fluoroanthradithiophenes}, volume={7}, ISSN={["2058-9689"]}, url={https://doi.org/10.1039/D1ME00158B}, DOI={10.1039/d1me00158b}, abstractNote={2-Dimensional brickwork packing is desirable for high mobility organic semiconductors. We synthesised acene derivatives that adopt this packing without using heavier group 14 elements to investigate substituent effects on bulk transport properties.}, number={4}, journal={MOLECULAR SYSTEMS DESIGN & ENGINEERING}, publisher={Royal Society of Chemistry (RSC)}, author={Thorley, Karl J. and Dremann, Derek and Iqbal, Hamna F. and Parkin, Sean R. and Jurchescu, Oana D. and Anthony, John E.}, year={2022}, month={Jan} }
 @article{ho_pei_qin_zhang_peng_angunawela_jones_yin_iqbal_reynolds_et al._2022, title={Importance of Electric-Field-Independent Mobilities in Thick-Film Organic Solar Cells}, volume={10}, ISSN={["1944-8252"]}, url={http://dx.doi.org/10.1021/acsami.2c11265}, DOI={10.1021/acsami.2c11265}, abstractNote={In organic solar cells (OSCs), a thick active layer usually yields a higher photocurrent with broader optical absorption than a thin active layer. In fact, a ∼300 nm thick active layer is more compatible with large-area processing methods and theoretically should be a better spot for efficiency optimization. However, the bottleneck of developing high-efficiency thick-film OSCs is the loss in fill factor (FF). The origin of the FF loss is not clearly understood, and there a direct method to identify photoactive materials for high-efficiency thick-film OSCs is lacking. Here, we demonstrate that the mobility field-dependent coefficient is an important parameter directly determining the FF loss in thick-film OSCs. Simulation results based on the drift-diffusion model reveal that a mobility field-dependent coefficient smaller than 10-3 (V/cm)-1/2 is required to maintain a good FF in thick-film devices. To confirm our simulation results, we studied the performance of two ternary bulk heterojunction (BHJ) blends, PTQ10:N3:PC71BM and PM6:N3:PC71BM. We found that the PTQ10 blend film has weaker field-dependent mobilities, giving rise to a more balanced electron-hole transport at low fields. While both the PM6 blend and PTQ10 blend yield good performance in thin-film devices (∼100 nm), only the PTQ10 blend can retain a FF = 74% with an active layer thickness of up to 300 nm. Combining the benefits of a higher JSC in thick-film devices, we achieved a PCE of 16.8% in a 300 nm thick PTQ10:N3:PC71BM OSC. Such a high FF in the thick-film PTQ10 blend is also consistent with the observation of lower charge recombination from light-intensity-dependent measurements and lower energetic disorder observed in photothermal deflection spectroscopy.}, journal={ACS APPLIED MATERIALS & INTERFACES}, publisher={American Chemical Society (ACS)}, author={Ho, Carr Hoi Yi and Pei, Yusen and Qin, Yunpeng and Zhang, Chujun and Peng, Zhengxing and Angunawela, Indunil and Jones, Austin L. and Yin, Hang and Iqbal, Hamna F. and Reynolds, John R. and et al.}, year={2022}, month={Oct} }
 @article{goetz_iqbal_bittle_hacker_pookpanratana_jurchescu_2022, title={Organic single crystals of charge-transfer complexes: model systems for the study of donor/acceptor interactions}, url={https://doi.org/10.1039/D1MH01214B}, DOI={10.1039/D1MH01214B}, abstractNote={Polymorphism in organic charge-transfer complexes induces a variation in electronic structure and sub-gap states which directly impact device physics. Single crystals are highly ordered, allowing for the measurement with reduced extrinsic factors.}, journal={Materials Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Goetz, Katelyn P. and Iqbal, Hamna F. and Bittle, Emily G. and Hacker, Christina A. and Pookpanratana, Sujitra and Jurchescu, Oana D.}, year={2022} }
 @article{iqbal_ai_thorley_chen_mcculloch_risko_anthony_jurchescu_2021, title={Suppressing bias stress degradation in high performance solution processed organic transistors operating in air}, url={https://doi.org/10.1038/s41467-021-22683-2}, DOI={10.1038/s41467-021-22683-2}, abstractNote={AbstractSolution processed organic field effect transistors can become ubiquitous in flexible optoelectronics. While progress in material and device design has been astonishing, low environmental and operational stabilities remain longstanding problems obstructing their immediate deployment in real world applications. Here, we introduce a strategy to identify the most probable and severe degradation pathways in organic transistors and then implement a method to eliminate the main sources of instabilities. Real time monitoring of the energetic distribution and transformation of electronic trap states during device operation, in conjunction with simulations, revealed the nature of traps responsible for performance degradation. With this information, we designed the most efficient encapsulation strategy for each device type, which resulted in fabrication of high performance, environmentally and operationally stable small molecule and polymeric transistors with consistent mobility and unparalleled threshold voltage shifts as low as 0.1 V under the application of high bias stress in air.}, journal={Nature Communications}, author={Iqbal, Hamna F. and Ai, Qianxiang and Thorley, Karl J. and Chen, Hu and McCulloch, Iain and Risko, Chad and Anthony, John E. and Jurchescu, Oana D.}, year={2021}, month={Apr} }
 @article{zeidell_ren_filston_iqbal_holland_bourland_anthony_jurchescu_2020, title={Organic Field‐Effect Transistors as Flexible, Tissue‐Equivalent Radiation Dosimeters in Medical Applications}, volume={7}, url={https://doi.org/10.1002/advs.202001522}, DOI={10.1002/advs.202001522}, abstractNote={AbstractRadiation therapy is one of the most prevalent procedures for cancer treatment, but the risks of malignancies induced by peripheral beam in healthy tissues surrounding the target is high. Therefore, being able to accurately measure the exposure dose is a critical aspect of patient care. Here a radiation detector based on an organic field‐effect transistor (RAD‐OFET) is introduced, an in vivo dosimeter that can be placed directly on a patient's skin to validate in real time the dose being delivered and ensure that for nearby regions an acceptable level of low dose is being received. This device reduces the errors faced by current technologies in approximating the dose profile in a patient's body, is sensitive for doses relevant to radiation treatment procedures, and robust when incorporated into conformal large‐area electronics. A model is proposed to describe the operation of RAD‐OFETs, based on the interplay between charge photogeneration and trapping.}, number={18}, journal={Advanced Science}, publisher={Wiley}, author={Zeidell, Andrew M. and Ren, Tong and Filston, David S. and Iqbal, Hamna F. and Holland, Emma and Bourland, J. Daniel and Anthony, John E. and Jurchescu, Oana D.}, year={2020}, month={Sep}, pages={2001522} }
 @article{waldrip_iqbal_wadsworth_mcculloch_jurchescu_2020, title={Organic thin-film transistors with flame-annealed contacts}, volume={5}, url={https://doi.org/10.1088/2058-8585/ab76e1}, DOI={10.1088/2058-8585/ab76e1}, abstractNote={Reducing contact resistance is critical to developing high-performance organic field-effect transistors (OFETs) since it impacts both the device mobility and switching speed. Charge injection and collection has been optimized by applying chemical treatments to the contacts, such as self-assembled monolayers (SAMs), oxide interlayers, or dopants. Here, we tested how flame annealing the surface of the electrodes impacts the interface and bulk components of the contact resistance, as well as the overall device performance. A butane micro torch was used to flash-anneal the gold electrodes, which allowed gold grains to crystallize into larger domains. We found that, along with the grain size, the surface roughness of the contacts was also increased. SAM treatment created a lower work function shift on a flame annealed electrode than when deposited on an untreated surface, due to the greater surface roughness. This resulted in a larger interface contact resistance. However, flame annealing also produced an order of magnitude reduction in the density of trap states in the semiconductor layer, which reduced the bulk contact resistance and channel resistance. These competing effects yielded OFETs with similar performance as untreated devices.}, number={1}, journal={Flexible and Printed Electronics}, publisher={IOP Publishing}, author={Waldrip, Matthew and Iqbal, Hamna F and Wadsworth, Andrew and McCulloch, Iain and Jurchescu, Oana D}, year={2020}, month={Mar}, pages={014015} }
 @article{iqbal_holland_anthony_jurchescu_2020, title={Real-time monitoring of trap dynamics reveals the electronic states that limit charge transport in crystalline organic semiconductors}, url={https://doi.org/10.1039/D0MH00706D}, DOI={10.1039/D0MH00706D}, abstractNote={Access to the dynamics of trap annihilation/generation resulting from isomer rearrangement identifies the performance-limiting processes in organic thin-film transistors.}, journal={Materials Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Iqbal, Hamna F. and Holland, Emma K. and Anthony, John E. and Jurchescu, Oana D.}, year={2020} }
 @article{haneef_zeidell_jurchescu_2020, title={Charge carrier traps in organic semiconductors: a review on the underlying physics and impact on electronic devices}, volume={8}, url={https://doi.org/10.1039/C9TC05695E}, DOI={10.1039/C9TC05695E}, abstractNote={The phenomenon of charge carrier traps in organic semiconductors and their impact on electronic devices are reviewed.}, number={3}, journal={Journal of Materials Chemistry C}, publisher={Royal Society of Chemistry (RSC)}, author={Haneef, Hamna F. and Zeidell, Andrew M. and Jurchescu, Oana D.}, year={2020}, pages={759–787} }