Polymer - based solar cells

Conjugated polymers are excellent candidates for use in low-cost electronics and photovoltaics (PV)1. Polymer-based solar cells have reached power conversion efficiencies of 5% in recent reports2–6. Deposition of organics by screen printing, doctor blading, inkjet printing, and spray deposition is possible because these materials can be made soluble. These techniques are required for the high-throughput roll-to-roll processing that will drive the cost of polymer-based PV down to a point where it can compete with current grid electricity. Additionally, these deposition techniques all take place at low temperature, which allows devices to be fabricated on plastic substrates for flexible devices. In addition to the inherent economics of high-throughput manufacturing, light weight and flexibility are qualities claimed to offer a reduction in the price of PV panels by reducing installation costs. Flexible PV also opens up niche markets like portable power generation and aesthetic PV in building design. We review current state-of-the-art techniques for making efficient polymer-based PV devices. We discuss the basic device operation, materials requirements, and current technical challenges in making more efficient solar cells. We hope this article will serve as a guide to new researchers in the field who plan to develop better material systems and optimize devices to push organic photovoltaic power conversion efficiencies above 10%.