ESR12: Metal-Oxide Based Interlayers for Organic and Perovskite Photovoltaics / Thesis

The University of Southern Denmark
Mehrad Ahmadpour/ PhD Thesis Download

Abstract

Thin-film solar cells including both organic (OSC) and perovskites (PSC) devices have emerged as an
excellent alternative to the traditional silicon wafer technology in the field of photovoltaic technologies.
The basic materials used in these devices provides the solar cells with unique properties such as low
weight, semi-transparency, mechanical flexibility and potentially low cost, which in turn opens up for
completely new application areas. OSC has recently achieved Power Conversion Efficiencies (PCE) of more
than 13%, and PSC has shown an outstanding PCE of more than 22%, whereas in both cases, their stability
still lacks significant improvements.
This work is dedicated to research on improving the performance, including device stability, of organic and
perovskite solar cells, using novel metal-oxide based interlayers. The thesis will initial focus on the
fabrication and optimization of DBP/C70 organic cells, where new developments towards integration of OSC
for usage in low-power consuming electronics will be shown. Specifically it is shown how efficient OSC
reaching very high output voltage above 6V can be developed by multi-stacked devices, applying efficient
interfaces between each sub-cell, and by optimized the thickness in the individual sub-cells. Integration of
novel reactive sputtered Molybdenum oxide (MoOx) layers will be demonstrated as a new method to
improve the stability of these organic solar cells, while maintaining a high device performance, compared to
cells made thermal evaporation of MoOx hole transport layer. This is obtained by development of
crystalline films with high work functions, which in the end lead to the improved device stability.
Based on the analysis on OSC devices, new metal-oxide based interlayers for PSC devices are also
investigated. Especially adaptation of NiO:Cu hole-transport layers are investigated alongside solvent
engineering approaches for developing high performing PSC devices. At the end, it is show that copper in
combination with specific electron transport layers leads to PSC with high performance and improved
device stability.