Sensing infrared light with an organic/inorganic hetero-junction

Organic and inorganic semiconductors are diverse in many of their physical properties but the combination of these can feature unexpected as well as unique physical properties. Here we report on an organic/inorganic hetero-junction which can readily be utilized for sensing infrared light. The used materials are highly boron doped crystalline silicon (100) and a soluble buckminster fullerene derivative. Despite the missing light absorption of silicon as well as the of the fullerene derivative for a wavelengths beyond 1.3 μm and 720 nm respectively, a hetero-junction of these materials absorbs in the infrared and generates a primary photo-current in the wavelength range from 1.3 to 3 μm. The simple preparation of the hetero-junction by a solution process of the fullerene derivative on top of the silicon wafer substrate, is technologically attractive in an economically viable way.