Donglai Zhong

All Publications

• A molecular design approach towards elastic and multifunctional polymer electronics. Nature communications Zheng, Y., Yu, Z., Zhang, S., Kong, X., Michaels, W., Wang, W., Chen, G., Liu, D., Lai, J., Prine, N., Zhang, W., Nikzad, S., Cooper, C. B., Zhong, D., Mun, J., Zhang, Z., Kang, J., Tok, J. B., McCulloch, I., Qin, J., Gu, X., Bao, Z. 2021; 12 (1): 5701

  Abstract

  Next-generation wearable electronics require enhanced mechanical robustness and device complexity. Besides previously reported softness and stretchability, desired merits for practical use include elasticity, solvent resistance, facilepatternability and high charge carrier mobility. Here, we show a molecular design concept that simultaneously achieves all these targeted properties in both polymeric semiconductors and dielectrics, without compromising electrical performance. This is enabled by covalently-embedded in-situ rubber matrix (iRUM) formation through good mixing of iRUM precursors with polymer electronic materials, and finely-controlled composite film morphology built on azide crosslinking chemistry which leverages different reactivities with C-H and C=C bonds. The high covalent crosslinking density results in both superior elasticity and solvent resistance. When applied in stretchable transistors, the iRUM-semiconductor film retained its mobility after stretching to 100% strain, and exhibited record-high mobility retention of 1 cm2 V-1 s-1 after 1000 stretching-releasing cycles at 50% strain. The cycling life was stably extended to 5000 cycles, five times longer than all reported semiconductors. Furthermore, we fabricated elastic transistors via consecutively photo-patterning of the dielectric and semiconducting layers, demonstrating the potential of solution-processed multilayer device manufacturing. The iRUM represents a molecule-level design approach towards robust skin-inspired electronics.

  View details for DOI 10.1038/s41467-021-25719-9

  View details for PubMedID 34588448

• A Design Strategy for Intrinsically Stretchable High-Performance Polymer Semiconductors: Incorporating Conjugated Rigid Fused-Rings with Bulky Side Groups. Journal of the American Chemical Society Liu, D., Mun, J., Chen, G., Schuster, N. J., Wang, W., Zheng, Y., Nikzad, S., Lai, J., Wu, Y., Zhong, D., Lin, Y., Lei, Y., Chen, Y., Gam, S., Chung, J. W., Yun, Y., Tok, J. B., Bao, Z. 2021

  Abstract

  Strategies to improve stretchability of polymer semiconductors, such as introducing flexible conjugation-breakers or adding flexible blocks, usually result in degraded electrical properties. In this work, we propose a concept to address this limitation, by introducing conjugated rigid fused-rings with optimized bulky side groups and maintaining a conjugated polymer backbone. Specifically, we investigated two classes of rigid fused-ring systems, namely, benzene-substituted dibenzothiopheno[6,5-b:6',5'-f]thieno[3,2-b]thiophene (Ph-DBTTT) and indacenodithiophene (IDT) systems, and identified molecules displaying optimized electrical and mechanical properties. In the IDT system, the polymer PIDT-3T-OC12-10% showed promising electrical and mechanical properties. In fully stretchable transistors, the polymer PIDT-3T-OC12-10% showed a mobility of 0.27 cm2 V-1 s-1 at 75% strain and maintained its mobility after being subjected to hundreds of stretching-releasing cycles at 25% strain. Our results underscore the intimate correlation between chemical structures, mechanical properties, and charge carrier mobility for polymer semiconductors. Our described molecular design approach will help to expedite the next generation of intrinsically stretchable high-performance polymer semiconductors.

  View details for DOI 10.1021/jacs.1c04984

  View details for PubMedID 34284578

• Monolithic optical microlithography of high-density elastic circuits. Science (New York, N.Y.) Zheng, Y. Q., Liu, Y., Zhong, D., Nikzad, S., Liu, S., Yu, Z., Liu, D., Wu, H. C., Zhu, C., Li, J., Tran, H., Tok, J. B., Bao, Z. 2021; 373 (6550): 88-94

  Abstract

  Polymeric electronic materials have enabled soft and stretchable electronics. However, the lack of a universal micro/nanofabrication method for skin-like and elastic circuits results in low device density and limited parallel signal recording and processing ability relative to silicon-based devices. We present a monolithic optical microlithographic process that directly micropatterns a set of elastic electronic materials by sequential ultraviolet light-triggered solubility modulation. We fabricated transistors with channel lengths of 2 micrometers at a density of 42,000 transistors per square centimeter. We fabricated elastic circuits including an XOR gate and a half adder, both of which are essential components for an arithmetic logic unit. Our process offers a route to realize wafer-level fabrication of complex, high-density, and multilayered elastic circuits with performance rivaling that of their rigid counterparts.

  View details for DOI 10.1126/science.abh3551

  View details for PubMedID 34210882