Optical Description of Mesostructured Organic–Inorganic Halide Perovskite Solar Cells

Abstract

Herein we describe both theoretically and experimentally the optical response of solution-processed organic−inorganic halide perovskite solar cells based on mesostructured scaffolds. We develop a rigorous theoretical model using a method based on the propagation of waves in layered media, which allows visualizing the way in which light is spatially distributed across the device and serves to quantify the fraction of light absorbed by each medium comprising the cell. The discrimination between productive and parasitic absorption yields an accurate determination of the internal quantum efficiency. State-of-the-art devices integrating mesoporous scaffolds infiltrated with perovskite are manufactured and characterized to support the calculations. This combined experimental and theoretical analysis provides a rational understanding of the optical behavior of perovskite cells and can be beneficial for the judicious design of devices with improved performance. Notably, our model justifies the presence of a solid perovskite capping layer in all of the highest efficiency perovskite solar cells based on thinner mesoporous scaffolds.O rganic−inorganic halide perovskite solar cells have driven a paradigm shift in photovoltaics (PV) since they are breaking with the sempiternal trade-off between power conversion efficiency and fabrication cost. 1−5 Not long after their inception, this solar cell concept is already striding ahead in the emerging PV efficiency race, having reached in the last 2 years certified efficiency values that significantly surpass all of the ones attained for other cells based on solution-processed materials and rapidly approaching existing commercial thin-film technologies. 6 This rapid progress has been based on improvements of fabrication methods, charge carrier materials, device architecture, morphology and crystallinity of the perovskite thin films, and the composition of the perovskite. 7−19 Another route to boost the efficiency of solar cell devices consists of the optimization of their optical design to maximize light harvesting and charge collection. 20 In this regard, efforts have been made to optimize the electro-optical performance of both materials 21−24 and devices. 25 In this respect, only cells that make use of flat, evaporated, perovskite layers have been modeled and, to the best of our knowledge, a detailed description of the optical behavior of the complete mesostructured device is still missing, especially understanding the difference between the optical properties of the perovskite when forming a solid crystalline film, in comparison with when infiltrated into a mesoporous scaffold.Herein we perform an in-depth experimental and theoretical analysis of the optical effects occurring in state-of-the-art solution-processed organic lead halide perovskite cells. We develop a rigorous theoretical model based on the transfer matrix formalism, 26 which allows us to calculate the electric field intensity within the layered structure and thus to visualize the effect of each component ...

Plasmonic Nanoparticles as Light-Harvesting Enhancers in Perovskite Solar Cells: A User’s Guide

“…43 Because shiny metallic coatings are not 44 or cannot be 45 used for this purpose in all cases, and in order to extract conclusions that are as general as possible, we will not assume the presence of any specific type of contact. Also, for the sake of comparison, similar estimations like those reported in Figure 1 are shown in Figure S3 in the Supporting Information for a perovskite film of different optical constants, namely, like those reported in ref (41). …”

Enhanced absorption in tandem solar cells by applying hydrogenated In2O3 as electrode

“…It should be also noted here that the highest efficiency for our perovskite tandem solar cells (around 25 %) is below Shockley-Queisser efficiency limit, which was however realized in some calculations [17][18][19][20][21][22] . The main underlying reason is that different electrical models and parameters are applied.…”

Efficient and environmental-friendly perovskite solar cells via embedding plasmonic nanoparticles: an optical simulation study on realistic device architectures

“…However, despite their high performance, there are still two major issues that must be addressed. Firstly, a further improvement of the light collection of the PSCs should be achieved [6], [7]. Additionally, a reduction of the PSCs' toxicity [8], due to the presence of pure lead (Pb) in the perovskite materials, should be attained for their further commercialization.…”

“…Pathak et al [18] and Roopak et al [19] explored Mie theory [20] and showed that silver, gold and aluminum nanoparticles, embedded inside a perovskite matrix, support plasmonic resonances of high magnitude with tunable resonance frequency and width by varying the size, shape or material. These results are very promising since plasmonic nanoparticles can induce light incoupling to the perovskite near its band edge (~650-800 nm) where it shows inferior photo response due to lower absorption in conjunction with increased reflection from the perovskite at that regime [6], [7]. Moreover, Carretero-Palacios S. et al [21], [22] theoretically exploited the effect of plasmonic enhancement by incorporating metallic nanoparticles of different shapes, sizes, concentrations and composition in methyl ammonium lead iodide perovskite (CH3NH3PbI3) absorbing layers assumed to be supported on a glass substrate and coated by a hole transporting material.…”