  Solution-processed, lead halide-based perovskite solar cells have overcome
important challenges over the recent years, offering low-cost and high solar
power conversion efficiencies. However, they still undergo unoptimized light
collection due mainly to the thin (~350 nm) polycrystalline absorber layers.
Moreover, their high toxicity (due to the presence of lead in the perovskite
crystalline structure) makes it necessary that the thickness of the absorber
layers to be further reduced, for their future commercialization, without
reducing the device performance. Here we aim to address these issues via
embedding spherical plasmonic nanoparticles of various sizes, composition,
concentrations, and vertical positions, for the first time in realistic
halide-based perovskite solar cells architecture, and to clarify their effect
on the absorption properties and enhancement. We theoretically show that
plasmon-enhanced near-field effects and scattering leads to a device
photocurrent enhancement of up to ~7.3% when silver spheres are embedded inside
the perovskite layer. Interestingly, the combination of silver spheres in
perovskite and aluminum spheres inside the hole transporting layer (PEDOT:PSS)
of the solar cell leads to an even further enhancement, of up to ~12%. This
approach allows the employment of much thinner perovskite layers in PSCs (up to
150 nm) to reach the same photocurrent as the nanoparticles-free device and
reducing thus significantly the toxicity of the device. Providing the
requirements related to the size, shape, position, composition, and
concentration of nanoparticles for the PSCs photocurrent enhancement, our study
establishes guidelines for a future development of highly-efficient,
environmentally friendly and low-cost plasmonic perovskite solar cells.
