Youth Chemistry Conference 3rd Youth Chemistry Conference | Page 7

GUEST LECTURES Dr. Askhat N. Jumabekov Assistant Professor Department of Physics School of Science and Humanities Nazarbayev University Perovskite solar cells: Prospects of device structure and architecture on low-cost and large-scale manufacturing Abstract Hybrid organic-inorganic perovskites have been identified as one of the most promising classes of materials for photovoltaic and optoelectronic applications, due to their excellent electronic and optical properties, combined with their ease of fabrication. The efficiency of perovskite solar cells (PSCs) has increased at a remarkably fast pace, with the current maximum certified power conversion efficiency (PCE) exceeding 25%. Conventional solid-state hybrid organic-inorganic perovskite-based solar cells have a sandwich type structure in which the perovskite absorber layer is positioned between bottom and top electrodes, typically a transparent conducting oxide (TCO) layer on glass, and an evaporated thin layer of gold or silver, respectively. Such an architecture for PCSs allows illumination of the cells only from the TCO side. Alternatively, the back-contact architecture offers the possibility of positioning both electrodes on one side of the absorber layer and shining light directly on the photoactive layer. 1,2 In contrast to conventional PSCs with sandwich-type structure, the back-contact approach has several advantages. First, fabrication and characterization of the entire back-contact electrode is done prior to deposition of the perovskite layer during the last step in device fabrication process. This effectively addresses the issue with the process sensitivity of the perovskite layer. Second, placing both electrodes on only one side of the perovskite layer reduces transmission losses. Third, once the device fabrication process is complete, the back-contact design gives further access to the perovskite photo-absorber layer for additional electro- optic optimization, for example by passivation of surface trap states, application of antireflective coatings as well as use of up- or/and down-converting layers at the perovskite/air interface. Additionally, this novel back-contact architecture allows illumination of the cell from both sides, which makes this technology suitable for application in tandem devices and smart windows. 3 References 1. P. Khoram, S. Brittman, W. I. Dzik, J. N. H. Reek, E. C. Garnett, Growth and characterization of pdms-stamped halide perovskite single microcrystals. J. Phys. Chem. C 120 (2016) 6475-6481. 2. L. M. Pazos-Outón, M. Szumilo, R. Lamboll, J. M. Richter, M. Crespo-Quesada, M. AbdiJalebi, H. J. Beeson, M. Vrućinić, M. Alsari, H. J. Snaith, B. Ehrler, R. H. Friend, F. Deschler, Photon recycling in lead iodide perovskite solar cells. Science 351(2016) 1430-1433. 3. A. N. Jumabekov, E. Della Gaspera, Z.-Q. Xu, A. S. R. Chesman, J. van Embden, S. A. Bonke, Q. Bao, D. Vak, U. Bach, Back-contacted hybrid organic-inorganic perovskite solar cells. J. Mater. Chem. C 4 (2016) 3125-3130.