Discovering how to efficiently convert solar energy into electrical/chemical energy is one of humanity’s greatest challenges in the 21st century. Among innovative photovoltaic approaches, quantum dots (QDs) solar cells (SC) have exhibited a rapid increase in energy conversion efficiency (ECE) and they are promising devices for their low-cost, theoretically predicted high efficiency, and large-scale solar energy conversion as an alternative to conventional solid-state semiconductor SC. However, the ECE is still quite low (~5-6%) due the presence of charge recombination processes instead of charge separation and collection inside the operating device [ChemPhysChem 11: 2290–2304.]. The control of the surface/interface physico-chemical phenomena regulating charge injection and transport is critical to obtain a breakthrough with respect to the present SC performance. Our research focuses on (i) investigating the injection properties in various oxide/QD systems; (ii) tailoring the electronic band structure of the complex system to maximize exciton separation, charge injection and transport; (iii) increasing significantly the ECE in SC.
Selected Published articles
Wheeler, D. A., Fitzmorris, B. C., Zhao, H. G., Ma, D., and Zhang, J. Z. (2011) Ultrafast Exciton Relaxation Dynamics of PbS and Core/Shell PbS/CdS Quantum Dots. Science China Chemistry, 54:2009–2015.
Wang, D., Baral, J. K., Zhao, H. G., Gonfa, B. A., Truong, V. V., Elkhakani, M. A., Izquierdo, R., Ma, D. (2011) Controlled Fabrication of PbS Quantum-Dot/Carbon-Nanotube Nano-architecture and its Significant Contribution to Near Infrared Photon-to-Current Conversion. Advanced Functional Materials, 21:4010-4018.
Zhao, H. G., Chaker, M., and Ma, D. (2011) Effect of CdS Shell Thickness on the Optical Properties of Water-soluble Amphiphilic Polymer Encapsulated PbS/CdS QDs. Journal of Material Chemistry, 21:17483-17491.
Zhao, H. G., Chaker, M., Wu, N., and Ma, D. (2011) Towards Controlled Synthesis and Better Understanding of Highly Luminescent PbS/CdS Core/shell Quantum Dots. Journal of Material Chemistry, 21:8898-8904. (Highlighted by RSC publishing)
Zhao, H. G., Wang, D., Chaker, M., and Ma, D. (2011) Effect of Different Types of Surface Ligands on the Structure and Optical Property of Water-soluble PbS Quantum Dots Encapsulated by Amphiphilic Polymers. The Journal of Physical Chemistry C, 115:1620-1626.
Zhao, H. G., Zhang, T. Wang, D., Chaker, M., and Ma, D. (2010) Two-step Approach to Synthesize Water-soluble Near-infrared Emitting Colloidal Quantum Dots via Amphiphilic Polymers. Chemical Communications, 46:5301-5303.
Zhao, H. G., Chaker, M., and Ma, D. (2010) Self-Selective Recovery of Photoluminescence in Amphiphilic Polymer Encapsulated PbS Quantum Dots. Physical Chemistry Chemical Physics, 12:14754-14761.
Wang, D., Zhao, H. G., Wu, N., Elkhakani, M. A., and Ma, D. (2010) Tuning the Charge-Transfer Property of PbS-Quantum Dot/TiO2-Nanobelt Nanohybrids via Quantum Confinement. The Journal of Physical Chemistry Letters, 1:1030-1035.
Zhang, T., Zhao, H. G., Riabinina, D., Chaker, M., and Ma, D. (2010) Concentration-Dependent Photoinduced Photoluminescence Enhancement in Colloidal PbS Quantum Dot Solution. The Journal of Physical Chemistry C, 114:10153-10159.
Zhao, H. G., Chaker, M., and Ma, D. (2009) Bimodal Photoluminescence during the Growth of PbS Quantum Dots. The Journal of Physical Chemistry C, 113:6497-6504.
Zhao, H. G., Ma, L. Gao, C., Shen, J. (2009) A Composite Scaffold of PLGA Microspheres/Fibrin Gel for Cartilage Tissue Engineering: Fabrication, Physical Properties, and Cell Responsiveness. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 88:240-249.
Zhao, H. G., Ma, L., Gong, Y., Gao, C., Shen, J. (2009) A Polylactide/Fibrin Gel Composite Scaffold for Cartilage Tissue Engineering: Fabrication and an in vitro Evaluation. Journal of Materials Science: Materials in Medicine, 20:135-143.
Zhao, H. G., Chaker, M., and Ma, D. (2010) Towards Synthesis of High-quality Water-soluble Near-infrared Emitting PbS Quantum Dots. 3e Colloque annuel du CQMF, Sherbrooke, Canada, October 7. (poster, provincial)
Zhao, H. G., Chaker, M., and Ma, D. (2010) Automatic Size-dependent Recovery of Photoluminescence of Water Soluble PbS Quantum Dots. 3e Colloque annuel du CQMF, (poster) Sherbrooke, Canada, October 7. (poster, provincial)
Zhao, H. G., Chaker, M., and Ma, D. (2009) Toward Development of High-quality Water-soluble PbS Quantum Dots. Materials Research Society Fall Conference, Boston, USA, December 1 to 5. (oral, international)
Zhao, H. G., and Ma, D. (2012) Synthesis and Characterization of Quantum Dots, in “Biosensors Based on Nanomaterials and Nanodevices” edited by Wu, N., and Li, J. Taylor & Francis, Chapter 2, 29 pages.