Mechanically Flexible Plasmonic Transparent Conducting Thin Films for Harvesting Photocurrent of Photodetector and Organic Solar Cell

Prof. Bhola Nath Pal (School of Materials Science and Technology, Indian Institute of Technology)

Tuesday, 9 December 2025, 13:45

Johannes Kepler University Linz, HS 12

Altenberger Straße 69, 4040 Linz, Austria

Abstract:

We developed a unique technique to grow the Ag clusters inside a TiO2 matrix (Ag-TiO2) through a low temperature (~100 oC) solution-processed synthesis technique. To fabricate mechanically flexible plasmonic transparent conductors, it required a two steps deposition process. In the 1st step Ag-TiO2 thin film is deposited in a solution processed technique, whereas in the second step either Ag or Au is deposited on top of Ag-TiO2 film by thermal evaporation process. The optical transparency of Ag/Ag-TiO2 and Au/Ag-TiO2 thin film are ~70% and ~85% respectively in the visible region whereas their conductivities are within the range 5-10 /. In a photodetector or a solar cell device, these electrodes have dual roles; one is its optical transparency that allow visible light to enter inside the devices, in addition these electrodes can generate plasmon induced photocurrent that effectively enhances the

photosensitivity of a photodetector or power conversion efficiency of a solar cell very significantly. Our recent work on organic photovoltaic (OPV) solar cells show that the open circuit voltage of the device can be enhanced by ~ two times by using these transparent electrodes without reducing its short circuit current that effectively increases the efficiency of

the OPV device by ~ two times w.r.t the reference ITO substrate device. This result indicating the formation of tandem cells by the plasmonic transparent conductor in addition to its use as transparent electrode, could be a remarkable technique to boost thin film solar cell efficiency.

Short Bio-data:

Dr. Bhola Nath Pal is a professor at School of Material Science and Technology, IIT(BHU), Varanasi, India. He did PhD from Indian Association for the Cultivation of Science, Kolkata, India. He was post-doctoral fellow at Johns Hopkins University, USA, Los Alamos National Laboratory, USA and at University of Queensland, Australia before he joined in IIT(BHU) in 2014. He has published more than 115 papers in peer reviewed international journals.