Organic Semi-transparent Photovoltaics for Energy Efficient Buildings

Abstract

Recent progress in bulk heterojunction organic photovoltaics (OPVs) is approaching the milestone of 20% in power conversion efficiency (PCE) by utilising novel non-fullerene acceptors (NFAs). In comparison to the traditional fullerene acceptors, the NFA acceptors have simpler synthetic methods, a suitable band gap that increases the overall active layer absorption, and tunable energy levels that favour the open-circuit voltage. Organic solar cells based on NFAs have boosted the efficiency of OPVs to over 17%, while significant improvements in device stability have also been reported. The progress of NFAs provides commercialization opportunities for printed and highly transparent and efficient OPVs, which enables the application of this technology in various niche markets. This thesis focuses on the progress of energy-efficient buildings, the importance of conventional Si-based photovoltaics for energy-efficient buildings, and finally, the potential of emerging semitransparent OPVs for building-integrated photovoltaics (BIPVs) and other applications. The experimental work presented in this thesis involves the development and fabrication of semitransparent OPVs and the evaluation of their electrical and optical performance for BIPV applications. The design of semitransparent OPVs is challenging due to the requirement for high transparency and efficiency. The thesis demonstrates the use of high-performance NFAs in a ternary fullerene blend and evaluates their efficiency on the basis of BIPV applications. Finally, the thesis concludes with a discussion of the potential applications of semitransparent OPVs. The literature and the experimental results suggest that semitransparent OPVs have the potential to provide a viable solution for energy-efficient buildings and other sectors where both visible light transmission and electricity generation are required. Overall, this study contributes to the field of semitransparent OPVs and provides a foundation for future research in this area.