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To improve light absorption, in this study, the narrow band gap highly-ordered free-standing hydrogenated amorphous germanium nanoparticles (a-Ge:H NPs) were introduced into the CH3NH3PbI3−x Cl x films. Here, the NPs were fabricated by means of the radio frequency plasma enhanced chemical vapour deposition system. The effects of hydrogen dilution ratio (RH) on the microstructure and bonding configuration of a-Ge:H NPs were investigated by Raman, transmission electron microscopy and Fourier transform infrared spectroscopy measurements. As RH increases, an improvement in the structure order of a-Ge:H NPs was observed. Compared with the pure CH3NH3PbI3−x Cl x films, the light absorption of the hybrid a-Ge:H NPs/CH3NH3PbI3−x Cl x active layers was improved, and the surface coverage of the hybrid active layers nearly reached 100%. This new finding provided a novel way to solve the universal unfavourable surface coverage problem that existed in the ultrasonic spray-coating process. Meanwhile, compared with the device that is based on pure CH3NH3PbI3−x Cl x films, due to the enhanced light absorption in the visible range, a ∼14.6% enhancement in the power conversion efficiency was achieved based on the hybrid a-Ge:H NPs/CH3NH3PbI3−x Cl x active layers.
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