Numerical investigation of the effects of copper sulfide nanoparticles on hole transport layer of thin-film organic solar cells

摘要

Incorporation of metal nanoparticles (NPs) into various layers of organic solar cells (OSCs) has become a popular means of enhancing device performances through increased light absorption by way of plasmon resonance effects. A number of NPs properties and device fabrication parameters should be considered when designing NPs-embedded OSCs for achieving optimum photovoltaic performance. Understanding the impact and mechanisms of photo-absorption with NPs in the solar cells becomes important, making numerical simulations for such investigations critical. Adopting the effective medium model in a numerical simulation; we have investigated charge transport and recombination dynamics of copper sulfide nanoparticles (CuS NPs)-doped hole transport layer (HTL) in OSC. The P3HT:PCBM blend bulk heterojunction (BHJ) solar absorber is used in modeling the devices. The CuS NPs-doping of the hole transport layer (HTL) was realized by introducing a thin modified hole selective layer (MHSL) between the HTL and the absorber. Non-ideal factors such as limited mobility, traps states, recombination dynamics and adjusted exciton generation profiles were considered to describe the solar cells. Enhanced conductivity, variations in the Fermi level offset at the interface and thickness of the MHSL were also taken into account to analyze device performances. The results were compared with experimentally measured device parameters, which are found to be in good agreement. These will greatly assist in understanding the physical processes in nanoparticles-doped OSCs.