Efficient and Cost Effective Solar Cells: New Materials for Improved Recombination and Charge Dissociation Losses in Organic Photovoltaics
Solar energy resources are vast: more energy hits the planet in one hour than humankind consumes in entire year. However, solar technologies have only been used to a limited degree in energy production thus far because of high costs.1 Organic solar cells2-21 offer the potential to change the landscape of how we produce and use energy. If developed into a mature technology, they present the opportunity to significantly reduce solar energy costs through earth-abundant materials, efficient installation, and roll-to-roll production. 6-8 Their properties and designs can be tuned and optimized via materials versatility, solution-based processing, and mechanical flexibility.8-10 In recent years, there have been numerous improvements in power conversion efficiencies, with the 8% threshold recently being crossed.22-24 While these efficiencies continue to be notably less than today’s commercial solar cells, the steady improvement in efficiencies has generated significant interest in their potential to become practical, widespread sources of energy production. However, in addition to key lifetime improvement needs, moving to power conversion efficiencies >10% is regarded as an important threshold for widespread deployment, and therefore, major materials and cell design advances are still needed. Achieving these developments will require a better understanding of organic solar cell loss mechanisms before high efficiencies can be achieved.