ECE SEMINAR

Speaker:    Prof. Gang Li - Department of Electric and Electronic Engineering, Research Institute for Smart Energy (RISE), The Hong Kong Polytechnic University

Title:         Organic Solar Cells towards 20% Efficiency – A Journey

Day:           Tuesday, August 8, 2023

Time:         2:00 p.m.

Room:        EQuad B418

Host:          Prof. Barry Rand

Abstract:    Organic solar cells (OSCs) and hybrid organic-inorganic metal halide perovskite solar cells (PSCs) are two of the most promising candidates for next generation printable photovoltaics primarily due to their high efficiency, printability, low cost etc. Organic semiconductors, due to the tightly bounded excitonic feature, tend to have drawbacks in achieving high efficiency. In this talk, I will present recent progress in solution processed organic solar cells, in which several approaches have been explored in achieving advances in power conversion efficiencies (PCEs) - now almost 20%. The several aspects covered include:

1. Progress in morphology control in non-fullerene acceptor OSCs
   • Achieving 19.3% binary OSCs (certified 18.9% PCE) via an unconventional non-monotonic intermediate state manipulation strategy
   • Formation and controlling of graded BHJ OSC with high efficiency and processability
   • New NFA for ternary OSC strategy enabling 19.9% OSC (certified 19.5% PCE, unpublished results)
2. From form-factor/application point of view, I will present works in (a) highly visibly transparent OSC with record performance of 5.35% LUE via optical and active layer engineering; (b) all solution process intrinsically stretchable semitransparent OSC; (c) multifunctional device called self-powered flexible energy supplier (SPFES) that integrates OSC, electrochromic supercapacitor and triboelectric nanogenerator

References:

1. “19.31% binary organic solar cell and low non-radiative recombination enabled by non-monotonic intermediate state transition”.  Nature Communications 14: 1760 (2023)
2. “Graded Bulk Heterojunction Enables High Efficiency Binary Organic Solar Cells Approaching 17% via Nonhalogenated Open Air Coating” Nature Communications 12 (1), 4815 (2021)
3. “Aperiodic band-pass electrode enables record-performance transparent organic photovoltaics,” Joule, Vol. 6, No. 8, 1918–1930, 2022.
4. “Intrinsically stretchable, semi-transparent organic photovoltaics with high efficiency and mechanical robustness via a full-solution process,” Energy Environ. Sci., 2023, DOI: 10.1039/D2EE03096A
5. “Tandem self-powered flexible electrochromic energy supplier for sustainable all-day operations,” Advanced Energy Materials, Vol. 12, No. 30, 2201042, 2022.

Bio: Gang Li is Sir Sze-yuen Chung Endowed Professor in Renewable Energy in the Department of Electric and Electronic Engineering, Associate Director of Research Institute of Smart Energy (RISE) in the Hong Kong Polytechnic University. He obtained his BS degree from Wuhan University in Space Physics, MS in Electrical Engineering and PhD in Condensed Matter Physics from Iowa State University in 2003. His research interests are on materials, device engineering and device physics in organic semiconductors and hybrid perovskite semiconductors, focusing on energy applications. He was a postdoc and research professor at UCLA, and VP of Solarmer Energy Inc. before coming to Hong Kong in 2016. He has been among Thomson Reuters/ Clarivate Analytics Highly Cited Researchers since 2014, published ~200 papers, with ~76,000 citations and h-index of 88.