23 March 2018 Congratulations to New ICFO PhD graduate

Dr. Quan Liu

Thesis Committee

Thesis Committee

Dr. Quan Liu graduated with a thesis in “Double Resonant Character in an Optical Cavity for High Performance and Stable Polymer Solar Cells”. Dr. Quan Liu received his Master degree at MTech, South China University of Technology, in China, before joining the Organic Nanostructured Photovoltaics research group led by UPC Prof. at ICFO Jordi Martorell. At ICFO, he centred his doctoral work on studying one-dimensional optical planar cavities to reach optimal broadband light trapping in thin film cells. Dr. Quan Liu’s thesis, entitled “Double Resonant Character in an Optical Cavity for High Performance and Stable Polymer Solar Cells”, has been supervised by UPC Prof. at ICFO Jordi Martorell.


Solution-processed thin film solar cells emerged as very promising photovoltaic technologies suitable for a low cost roll-to-roll upscale production. Such thin film character also ensures lightweight and flexibility for the solar cell modules, making them ideal for a wide variety of applications where silicon panels cannot be used. In addition to the above-mentioned advantages, common in all solution-processed thin film technologies, polymer solar cells (PSCs) have a unique semitransparency, which makes them very useful for solar window applications and very competitive in building integrated photovoltaics.

In recent years, a remarkable progress has been achieved in the field of PSCs. The power conversion efficiency of PSCs has already surpassed the 11% barrier. However, to be able to eventually compete with other solution-processed thin film technologies, such device efficiency must be further improved. Given the low charge carrier mobility in commonly used organic p-conjugated semiconductors, the tradeoff between optical absorption and charge collection, limits the thickness of the majority of photoactive layers currently being used to approximately 100 nm. To overcome the limited light absorption in such thin active layers, an adequate optical management becomes very important. Ideally, a light absorption or short-circuit current enhancement should be achieved without affecting the other photovoltaic parameters, such as the photovoltaic device open circuit voltage and fill factor.

Thesis Committee

Prof Maiano Campoy, ICMAB, UAB
Prof Dr Gerasimos Konstantatos, ICFO
Prof Alejandro Pérez, IREC