Properties of functional layers in inverted thin film organic solar cells

Thin film organic photovoltaic cell (TFOSC) is increasingly becoming an alternative solar energy converter and offering several potential advantages over inorganic molecules based devices. Tremendous research progresses have been made on the realization of TFOSC in the last two decades. Despite intensive research efforts towards reaching the required 10% power conversion efficiency (PCE) threshold, the device environmental stability and the constant requirement for high vacuum top metal electrode deposition still remain the major challenges. One of the encouraging findings in terms of alternative device architecture that caters for these challenges is the inverted device architecture of polymer solar cells. This review covers recent progress and approaches that have been achieved to improve device performance due to the changes in properties and structures of the constituent layers such as electrodes, active layers and buffer layers of the inverted organic solar cell.