光学常数(折射率和消光系数)是聚合物半导体薄膜器件结构设计和性能优化的重要参数。借助于Forouhi-Bloomer (F-B)色散模型，通过拟合P3HT(聚3-己基噻吩):PCBM([6,6]-苯基-C61-丁酸甲酯)和MEH-PPV(聚[2-甲氧基-5-(2-乙基己氧基)-1,4-对苯乙炔]):PCBM 体异质结薄膜以及聚合物导电薄膜PEDOT(聚3,4-乙烯二氧噻吩):PSS(聚苯乙烯磺酸)的反射率，计算得到其光学常数和厚度，拟合得到的反射率曲线和实验曲线符合良好。厚度拟合结果与表面轮廓仪测量结果误差小于3%。基于该方法，进一步分析了热退火对P3HT:PCBM 薄膜表面形貌和光学常数的影响。研究结果表明，P3HT:PCBM 薄膜在110 ℃退火后，折射率在550~700 nm 波长范围内的峰值由1.95上升到2.16，同时，消光系数的峰值波长向长波长方向移动。

Optical constants (refractive index and extinction coefficient) of polymer semiconductor thin films are of great significance to perform optimization design. The Forouhi-Bloomer (F-B) dispersion models are applied by fitting reflectivity curves of P3HT (poly(3-hexylthiophene)):PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), MEH-PPV (poly[2-methoxy-5-(2′ethyl-hexyloxy)-1,4-phenylenevinylene]):PCBM, and PEDOT (poly (3,4-ethylene dioxythiophene)):PSS (polystyrenesulfonate). The optical constants and thickness are calculated, and two reflectance curves fit well. The thickness mismatch between the fitting and measurement results is less than 3%. Based on this method, the influence of thermal annealing on the P3HT:PCBM film surface morphology and the optical constants is analyzed. The maximum refraction index of P3HT:PCBM increases from 1.95 to 2.16 in the wavelength range of 550 nm to 700 nm after the thermal annealing process at 110 ℃ and the peak of extinction coefficient shifts to longer wavelength.