Optoelectronics

Solar cell and perovskites
Photographer: Olov Planthaber

We are a multidisciplinary team focusing on solution-processed optoelectronic materials and devices, with a passion for both fundamental science and new applications of these materials and devices.

Optoelectronic devices, such as light-emitting diodes (LEDs), solar cells, photodetectors, lasers and optical transmitters and receivers, are an important part in maintaining a sustainable world. The emergence of exceptional solution-processed semiconductors, including organic semiconductors and metal halide perovskites, offers great opportunities for developing new generations of optoelectronic devices that are of high performance, cost-effective, and integrable with other technological systems. 

We have developed a worldwide professional network for collaborations and are also actively engaging in collaborations with industry partners. 


News

Portrait Feng Gao.

Creating the flexible X-ray technology of the future

Professor Feng Gao has been granted SEK 31 million from the Knut and Alice Wallenberg Foundation over five years to develop a new type of X-ray technology. The goal is a flexible material that can improve X-ray detector image quality.

Two pipettes poring liquids on to a disk.

Research for a sustainable future in ten new projects

Photosynthetic materials, two-dimensional noble metals and sustainable semiconductors are some of the projects at LiU that have been granted funding from the research programme Wallenberg initiative materials science for sustainability – WISE.

Building a new lab at LiU

This summer, Dr Alex Gillett is arriving at LiU from the University of Cambridge, UK. He has been awarded a Wallenberg Academy Fellows grant and will use the funding to build his own lab to conduct research in the field of optoelectronics.

Materials

Organic semiconductors

Organic semiconductors have great potential in low-cost and large-area device applications, benefiting from cheap manufacturing processes such as solution-based roll-to-roll printing.
All device applications previously dominated by inorganic semiconductors have presented opportunities for their organic counterparts. Such applications include solar cells, LEDs, field-effect transistors, lasers, and memory devices.

 

Metal halide perovskites

Metal halide perovskites have emerged as one of the most popular semiconducting materials since 2009. They have shown unique properties, including:

Tunable bandgap

High absorption coefficient

Broad absorption spectrum

High charge carrier mobility

Long charge diffusion lengths

These properties enable metal halide perovskites to be used in a broad range of photovoltaics and other optoelectronic applications.

Lead free perovskites /Lead free metal halides

The state-of-the-art halide perovskites used for high-performance optoelectronic devices contain toxic lead (Pb). It is therefore attractive to develop lead free perovskites or perovskite alike materials with as good properties as the lead containing counterparts. These new materials provide a rich library to investigate fundamental optoelectronic properties and bring about new possibilities to explore the spintronic properties (e.g. when magnetic ions are involved). 

Optoelectronic devices

Organic solar cell with the aktive layer Pm6:Y6Organic solar cell with the aktive layer Pm6:Y6 Photo credit Olov PlanthaberSolar cells

Solar power is an ideal source for renewable and clean energy. Solar cells are semiconducting devices which can directly convert solar energy into electricity. 
The current solar cell market is dominated by silicon-based devices, with just over 2% of global electricity coming from solar in 2019. The emerging solution-processed solar cells based on organic semiconductors and metal halide perovskites have shown great potential to significantly promote the widespread use of the solar cell technology owing to their advantages of both high performance and low cost. 

Perovskite quantum dotsPerovskite quantum dots Photo credit Olov PlanthaberLEDs

Lighting and displays products are vital electric devices in our daily life, which also account for the largest portion of electricity consumption. LEDs are semiconductor light sources, which emit light when current flows through them. LEDs are considered the most promising energy-efficient technologies for lighting and displays.

Metal halide perovskites demonstrate strong photoluminescence and tunable emission colours, making them a promising candidate for the next generation of highly efficient LEDs.


A combined optical transmitter and receiverA combined optical transmitter and receiver Photo credit Magnus JohanssonOther devices

Photodetectors and optical receivers are sensors of light, which can convert light signals into electric signals. They have wide applications, such as optical communication and medical/ healthcare instruments.

Lasers are unusual light sources. They emit a very narrow beam of monochromatic light that is amplified and coherent. Lasers have a variety of applications, ranging from precision cutting tools to communications and scientific instruments.


Research and funding

Research

The Optoelectronic group lead by Prof. Gao dedicates its efforts to energy devices, with the ambition to both improve device performance and understand the underlying fundamentals. Their current investigations include organic semiconductors and metal halide perovskites, with research focuses such as:

  • Fullerene-free organic solar cells (OSCs) (see our Review article in Nature Materials). We are interested in fundamental working mechanisms of OSCs (e.g. voltage losses in Nature Energy, Nature Materials, and Nature Energy; at the same time, we also collaborate with our partners to develop OSCs towards practical applications (e.g. indoor applications of OSCs in Nature Energy, and green solvent processing of OSCs in Nature Energy).
  • Perovskite solar cells. We focus on developing stable perovskite solar cells and understanding the degradation mechanisms (e.g. stable perovskite solar cells in Nature)
  • Perovskite LEDs (see our Review article in Nature Materials). We aim to develop high-performance perovskite LEDs with different colours (e.g. near infrared in Nature Photonics and blue in Nature Communications), understand the mechanisms (e.g. operational mechanisms in Nature Communications, chemical interactions for high-efficiency and stable perovskite LEDs in Nature Communications and Joule), and explore new applications (e.g. bidirectional optical signal transmission in Nature Electronics)
  • Lead-free perovskites (see our Review article on lead-free double perovskites in Advanced Materials). We focus on new materials development (e.g. iron-doped double perovskites in Science Advances) and the understanding of fundamental properties (e.g. self-trapping in double perovskites in Science Advances).

Publications

2024

Nakul Jain, Rokas Jasiunas, Xiane Li, Huotian Zhang, Jiehao Fu, Rui Zhang, Li Gang, Mats Fahlman, Vidmantas Gulbinas, Feng Gao (2024) The Role of Thermally Activated Charge Separation in Organic Solar Cells Advanced Energy Materials (Article in journal) Continue to DOI
Yanmei He, Xinyi Cai, Xiaochen Wang, Mikkel Baldtzer Liisberg, Jakub Dostal, Muyi Zhang, Miroslav Kloz, Feng Gao, Tonu Pullerits, Junsheng Chen (2024) Unveiling Mechanism of Temperature-Dependent Self-Trapped Exciton Emission in 1D Hybrid Organic-Inorganic Tin Halide for Advanced Thermography Advanced Optical Materials (Article in journal) Continue to DOI
Bei Yang, Xiaoke Liu, Li Wan, Wei-Xin Ni, Ni Yang, Jianhui Hou, Feng Gao (2024) The impact of reabsorption effect on composition analysis of organic semiconductors SCIENCE CHINA-MATERIALS (Article in journal) Continue to DOI
Chencheng Peng, Ben Chen, Xiaoke Liu, Runda Guo, Zhiyuan He, Feihu Zhang, Xiping He, Liang Sun, Zhirong Liu, Yan Xiong, Feng Gao, Lei Wang (2024) High-Performance Thermally Evaporated Blue Perovskite Light-Emitting Diodes Enabled by Post-Evaporation Passivation Chemical Engineering Journal, Vol. 499, Article 155955 (Article in journal) Continue to DOI
Zihao Wen, Rongkun Zhou, Shiping Peng, Yijie Shi, Rui Zhang, Zilong Zheng, Feng Gao, Yi Zhao (2024) Impact of solvent processing on the PM6/Y6 morphology and charge transfer in organic solar cells Journal of Materials Chemistry C, Vol. 12, p. 17215-17222 (Article in journal) Continue to DOI
Jionghua Wu, Renjie Wang, Rui Zhang, Giuseppe Portale, Eduardo Solano, Xiaoke Liu, Feng Gao (2024) Lattice reconstruction for mixed-halide blue perovskite light-emitting diodes with high brightness, outstanding color stability and low efficiency roll-off SCIENCE CHINA-MATERIALS (Article in journal) Continue to DOI
Hongwei Lei, Utkarsh Singh, Fuxiang Ji, Tinghao Lin, Libor Kobera, Yuequn Shang, Xinyi Cai, Weihua Ning, Andrii Mahun, Sabina Abbrent, Zuojun Tan, Jiri Brus, Dehui Li, Sergey Simak, Igor Abrikosov, Feng Gao (2024) Palladium-Doped Cs2AgBiBr6 with 1300 nm Near-Infrared Photoresponse Small (Article in journal) Continue to DOI
Xining Chen, Fu Yang, Linhao Yuan, Shihao Huang, Hao Gu, Xiaoxiao Wu, Yunxiu Shen, Yujin Chen, Ning Li, Hans-Joachim Egelhaaf, Christoph J. Brabec, Rui Zhang, Feng Gao, Yaowen Li, Yongfang Li (2024) Perfluoroalkylsulfonyl ammonium for humidity- resistant printing high-performance phase-pure FAPbI3 perovskite solar cells and modules Joule, Vol. 8 (Article in journal) Continue to DOI
Eva M. Herzig, Feng Gao, Jonas Bergqvist, Maria A. Loi, Sebastian B. Meier (2024) Commentary Harmonizing organic photovoltaics research and development among academia and industry Joule, Vol. 8 (Article in journal) Continue to DOI
Tiefeng Liu, Gulzada Beket, Qifan Li, Qilun Zhang, Sang Young Jeong, Chi-Yuan Yang, Jun-Da Huang, Yuxuan Li, Marc-Antoine Stoeckel, Miao Xiong, Tom van der Pol, Jonas Bergqvist, Han Young Woo, Feng Gao, Mats Fahlman, Thomas Osterberg, Simone Fabiano (2024) A Polymeric Two-in-One Electron Transport Layer and Transparent Electrode for Efficient Indoor All-Organic Solar Cells Advanced Science (Article in journal) Continue to DOI
Lingeswaran Arunagiri, Feng Gao (2024) Molecule doping enables high-quality perovskite junctions for all-perovskite tandem solar cells NATIONAL SCIENCE REVIEW, Vol. 11 (Article in journal) Continue to DOI
Yun Gao, Hongjin Li, Xingliang Dai, Xingjian Ying, Zhe Liu, JiaJun Qin, Jie Guo, Zhongkang Han, Yujing Zhang, Meiyi Zhu, Xiaohui Wu, Qiuting Cai, Yixing Yang, Linrun Feng, Xiaoyu Zhang, Jingyun Huang, Haiping He, Feng Gao, Zhizhen Ye (2024) Microsecond-response perovskite light-emitting diodes for active-matrix displays NATURE ELECTRONICS, Vol. 7 (Article in journal) Continue to DOI
Ziming Chen, Robert L. Z. Hoye, Hin-Lap Yip, Nadesh Fiuza-Maneiro, Iago Lopez-Fernandez, Clara Otero-Martinez, Lakshminarayana Polavarapu, Navendu Mondal, Alessandro Mirabelli, Miguel Anaya, Samuel D. Stranks, Hui Liu, Guangyi Shi, Zhengguo Xiao, Nakyung Kim, Yunna Kim, Byungha Shin, Jinquan Shi, Mengxia Liu, Qianpeng Zhang, Zhiyong Fan, James C. Loy, Lianfeng Zhao, Barry P. Rand, Habibul Arfin, Sajid Saikia, Angshuman Nag, Chen Zou, Lih Y. Lin, Hengyang Xiang, Haibo Zeng, Denghui Liu, Shi-Jian Su, Chenhui Wang, Haizheng Zhong, Tong-Tong Xuan, Rong-Jun Xie, Chunxiong Bao, Feng Gao, Xiang Gao, Chuanjiang Qin, Young-Hoon Kim, Matthew C. Beard (2024) Roadmap on perovskite light-emitting diodes JOURNAL OF PHYSICS-PHOTONICS, Vol. 6, Article 032501 (Article in journal) Continue to DOI
Shaobing Xiong, Fuyu Tian, Feng Wang, Aiping Cao, Zeng Chen, Sheng Jiang, Di Li, Bin Xu, Hongbo Wu, Yefan Zhang, Hongwei Qiao, Zaifei Ma, Jianxin Tang, Haiming Zhu, Yefeng Yao, Xianjie Liu, Lijun Zhang, Zhenrong Sun, Mats Fahlman, Junhao Chu, Feng Gao, Qinye Bao (2024) Reducing nonradiative recombination for highly efficient inverted perovskite solar cells via a synergistic bimolecular interface Nature Communications, Vol. 15, Article 5607 (Article in journal) Continue to DOI
Feng Gao (2024) Record-high efficiency perovskite LEDs achieved by accelerating radiative recombination SCIENCE CHINA-MATERIALS (Article in journal) Continue to DOI

Coworkers

Two male scientists walks and talks in a hallway.
Principal research engineer Weihua Ning and professor Feng Gao at the Department of Physics, Chemistry and Biology. Photographer: Thor Balkhed

Group and Supervision

Prof. Feng Gao is deeply involved in both the scientific and career development of his group members. The senior researchers in his group have been awarded the prestigious VR Staring Grant, Marie Skłodowska-Curie Individual Fellowship, VINNMER Fellowship.

He also values the exchange of ideas: he has sponsored members of his group in exchanges to Cambridge, Oxford and EPFL, and his group has hosted visiting students and scholars from Cambridge, Zhejiang University, Nanjing University, Nanjing Tech University, Shenzhen University, Queen Mary University of London, and more.

Contact

Organisation