Opto-electronic device simulation of thin-film silicon solar cells requires a set of many input parameters for the electronic properties of amorphous and microcrystalline silicon. In this paper, a systematic determination of these is performed by inverse modeling and particle swarm optimization with experimental and simulated current-voltage characteristics of amorphous and microcrystalline silicon pin diodes, both in the dark and under illumination. The parameters are validated by additional experiments and simulations of the temperature-dependent dark current, of spectrally selective illumination, and of the external quantum efficiency of the amorphous and microcrystalline silicon diode, respectively. The validation of the input parameters is complemented by simulation of a tandem solar cell with the amorphous and the microcrystalline silicon input parameters. Simulation and experiment (spectrally dependent current-voltage characteristics and external quantum efficiency) of such a tandem solar cell show good agreement. Sensitivity studies on different sets of input parameters for the inverse modeling process are also presented.