Studies of active layer morphology in bulk-heterojunction polymer based solar cells using optical and force microscopy methods

Abstract

Photovoltaics deal with harnessing sunlight and subsequent conversion into electrical energy. Efficient photovoltaic solar cells based on inorganic semiconductors have developed considerably [1] since the first realization of silicon solar cells in 1954 from Bell Laboratory [2]. To date, silicon based cells with power conversion efficiency up to 30 – 40% are still leading technology in the photovoltaic market. However, the costs of silicon based cells are still not comparable to other conventional sources of energy, primarily due to the large-area requirement of harnessing the sunlight. An approach for roll to roll production of solar cells at low cost is to utilize as organic semiconducting materials that can be processed under less demanding conditions. Research on organic based photovoltaics have been pursued for more than 20 years, however, within the last decade this research field has made considerable improvement with higher efficiency and reliability to make it commercially feasible [3, 4], [5].