Solar cell and perovskites
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. 


Materials Show/Hide content

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 devises Show/Hide content

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 Show/Hide content


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 Show/Hide content


Tiankai Zhang, Feng Wang, Hak-Beom Kim, In-Woo Choi, Chuan Fei Wang, Eunkyung Cho, Rafal Konefal, Yuttapoom Puttisong, Kosuke Terado, Libor Kobera, Mengyun Chen, Mei Yang, Sai Bai, Bowen Yang, Jiajia Suo, Shih-Chi Yang, Xianjie Liu, Fan Fu, Hiroyuki Yoshida, Weimin Chen, Jiri Brus, Veaceslav Coropceanu, Anders Hagfeldt, Jean-Luc Bredas, Mats Fahlman, Dong Suk Kim, Zhang-Jun Hu, Feng Gao (2022) Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells Science, Vol. 377, p. 495-501 Continue to DOI

Coworkers Show/Hide content

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. 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.

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