A family of novel (X-TATAT)n-type conjugated polymers based on the carbazole (X), thiophene (T), and benzoxadiazole (A) moieties is designed and explored as electron-donor materials for organic bulk heterojunction solar cells. Incorporation of the branched side chains of different size and shape affects significantly the optoelectronic properties of the materials, particularly frontier energy levels of polymers translated to the open circuit voltages of the photovoltaic cells. The revealed unprecedented correlation between the parameters of the solar cells (VOC, fill factor (FF), JSC) and bulkiness of the alkyl side chains provides useful guidelines for rational design of novel materials for organic photovoltaics. (Figure presented.).
- conjugated polymers
- polymer solar cells