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

Prestigious physics award for Feng Gao

This year's Göran Gustafsson Prize in Physics goes to LiU professor Feng Gao. His research focuses on how new materials can be used for the next generation of solar cells and LEDs, among other things. The total prize money is SEK 7.5 million.

Researcher hold a glowing sheet of glass with tweezers.

Next generation LEDs are cheap and sustainable

Cost, technical performance and environmental impact 鈥� these are the three most important aspects for a new type of LED technology to have a broad commercial impact on society. This has been demonstrated by LiU-researchers in a new study.

A beaker filled with water where a small solar cell is dissolved.

The next-generation solar cell is fully recyclable

In a study published in Nature, researchers at LiU have developed a method to recycle all parts of a perovskite solar cell repeatedly without environmentally hazardous solvents. The recycled solar cell has the same efficiency as the original one.

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

Funding

The Optoelectronic Unit is mainly supported by the following funding agencies:

Publications

2025

Beier Hu, Tiankai Zhang, Longren Li, Haoqing Ning, Ganghong Min, Tong Wang, Mengyun Chen, Jiaxin Pan, Niansheng Xu, Thomas J. Macdonald, Feng Gao, Igal Levine, Ziming Chen, Artem A. Bakulin (2025) Advanced Materials (Article in journal)

Zhangwei He, Feng Wang, Yiman Dong, Yuling Zhang, Runnan Yu, Feng Gao, Zhan'ao Tan (2025) NATIONAL SCIENCE REVIEW, Vol. 12, Article nwaf097 (Article in journal)

Oleg Dimitriev, Huotian Zhang, Anna Dávid, Olof Eskilsson, Daniel Aili, Lukas Marcos Celada, Peter Olsen, Feng Gao, Mats Fahlman (2025) Cellulose (Article in journal)

Jiajun Qin, Jia Zhang, Xianjie Liu, Yu Wang, Heyong Wang, Utkarsh Singh, Yanyan Wang, Haoliang Wang, Tianxiang Hu, Yiqiang Zhan, Yipeng Tang, Bin Hu, Constantin Bach, Carsten Deibel, Wei-Xin Ni, Sergey Simak, Igor Abrikosov, Mats Fahlman, Feng Gao (2025) Nature Materials (Article in journal)

Rokas Jasiunas, Vidmantas Jasinskas, Jianwei Yu, Nakul Jain, Xuehong Zhou, Jun Yuan, Rui Zhang, Huotian Zhang, Bei Yang, Andrius Gelzinis, Yingping Zou, Vidmantas Gulbinas, Feng Gao (2025) Organic electronics, Vol. 140, Article 107211 (Article in journal)

Ao Liu, Jun Xi, Hanlin Cen, Jinfei Dai, Yi Yang, Cheng Liu, Shuai Guo, Xiaofang Lie, Xiaotian Guo, Feng Yang, Meng Li, Haoxuan Li, Fei Zhang, Huagui La, Fan Fui, Shuaifeng Hu, Junke Wang, Seongrok Seo, Henry J. Snaith, Jinghui Li, Jiajun Luo, Hongjin Lim, Yun Gao, Xingliang Dai, Jia Zhang, Feng Gao, Zhengxun Lai, You Meng, Johnny C. Ho, Wen Lit, Yuntao Wu, Liping Du, Sai Baia, Huihui Zhu, Xianhang Lin, Can Deng, Liyi Yang, Liu Tang, Ahmad Imtia, Hanxiang Zhi, Xi Lu, Heng Li, Xiangyu Sun, Yicheng Zhao, Jian Xu, Xiaojian She, Jafar Iqbal Khany, Guanglong Ding, Su-Ting Han, Ye Zhou, Ruifu Zhou, Jang-Sik Lee, Geonwoong Park, Youjin Reo, Yong-Young Noh (2025) MATERIALS TODAY ELECTRONICS, Vol. 11, Article 100138 (Article in journal)

Sankaran Ramesh, Yonghong Wang, Pavel Chabera, Rafael Araujo, Mustafa Aboulsaad, Tomas Edvinsson, Feng Gao, Toenu Pullerits (2025) Advanced Optical Materials (Article in journal)

Xun Xiao, Niansheng Xu, Xueyu Tian, Tiankai Zhang, Bingzheng Wang, Xiaoming Wang, Yeming Xian, Chunyuan Lu, Xiangyu Ou, Yanfa Yan, Licheng Sun, Fengqi You, Feng Gao (2025) Nature (Article in journal)

Yong Wang, Yu Wang, Tiarnan A. S. Doherty, Samuel D. Stranks, Feng Gao, Deren Yang (2025) Nature Reviews Chemistry (Article, review/survey)

Chao Li, Jiali Song, Hanjian Lai, Huotian Zhang, Rongkun Zhou, Jinqiu Xu, Haodong Huang, Liming Liu, Jiaxin Gao, Yuxuan Li, Min Hun Jee, Zilong Zheng, Sha Liu, Jun Yan, Xian-Kai Chen, Zheng Tang, Chen Zhang, Han Young Woo, Feng He, Feng Gao, He Yan, Yanming Sun (2025) Nature Materials (Article in journal)

Zhiqi Li, Qi Wei, Yu Wang, Cong Tao, Yatao Zou, Xiaowang Liu, Ziwei Li, Zhongbin Wu, Mingjie Li, Wenbin Guo, Gang Li, Weidong Xu, Feng Gao (2025) Nature Communications, Vol. 16, Article 927 (Article in journal)

Chenghao Duan, Kaicheng Zhang, Zijian Peng, Shiang Li, Feilin Zou, Feng Wang, Jiong Li, Zheng Zhang, Chang Chen, Qiliang Zhu, Jianhang Qiu, Xinhui Lu, Ning Li, Liming Ding, Christoph J. Brabec, Feng Gao, Keyou Yan (2025) Nature, Vol. 637, p. 1111-1117 (Article in journal)

Haiyang Chen, Yuting Huang, Rui Zhang, Hongyu Mou, Junyuan Ding, Jiadong Zhou, Zukun Wang, Hongxiang Li, Weijie Chen, Juan Zhu, Qinrong Cheng, Hao Gu, Xiaoxiao Wu, Tianjiao Zhang, Yingyi Wang, Haiming Zhu, Zengqi Xie, Feng Gao, Yaowen Li, Yongfang Li (2025) Nature Materials (Article in journal)

Muyi Zhang, Xiaotian Ma, John Laurence Esguerra, Hongling Yu, Olof Hjelm, Jiashuo Li, Feng Gao (2025) Nature Sustainability (Article, review/survey)

Ping Cai, Can Song, Yating Du, Jianbin Wang, Jing Wang, Lixian Sun, Feng Gao, Qifan Xue (2025) Advanced Functional Materials (Article, review/survey)

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 Sk艂odowska-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.

Coworkers

Lingeswaran Arunagiri

Postdoc

Gangadhar Banappanavar

Professor, Head of Unit

Associate Professor, Docent

Associate Professor, Docent

Associate Professor, Docent

Principal Research Engineer

Contact

Principal investigator

Organisation

Electronic and photonic materials (EFM)

Our division's research is focused on the development of organic electronics for energy conversion and storage.

Department of Physics, Chemistry and Biology (IFM)

Undergraduate teaching and research in the areas of biology, chemistry, materials and applied physics and theory and modelling are conducted at this department.

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