Ellipsometric study on the optical property of UV exposed MEH-PPV polymer film

We performed ellipsometric analysis on the effect of Ultra-Violet (UV) light exposure to the poly(2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylenevinylene) (MEH-PPV) films. The measured dielectric function spectrum of the MEH-PPV film showed the consistent decrease of absorption coefficients with the UV light exposure time, especially at the ordinary axis. This work notes that UV light protection method should be included in the process of MEH-PPV films for the optical device applications to prevent the significant change of optical property of the film and to maintain its efficient absorption of sunlight for solar cell devices.