We illustrate the important trade-off between far-field scattering effects, which have the potential to provide increased optical path length over broad bands, and parasitic absorption due to the excitation of localized surface plasmon resonances in metal nanoparticle arrays. Via detailed comparison of photocurrent enhancements given by Au, Ag and Al nanostructures on thin-film GaAs devices we reveal that parasitic losses can be mitigated through a careful choice of scattering medium. Absorption at the plasmon resonance in Au and Ag structures occurs in the visible spectrum, impairing device performance. In contrast, exploiting Al nanoparticle arrays results in a blue shift of the resonance, enabling the first demonstration of truly broadband plasmon enhanced photocurrent and a 22% integrated efficiency enhancement.

We present a multi-dimensional model for comprehensive simulations of solar cells (SCs), considering both electromagnetic and electronic properties. Typical homojunction and heterojunction gallium arsenide SCs were simulated in different spatial dimensions. When considering one-dimensional problems, the model performs carrier transport calculations following a Beer-Lambert optical absorption approximation. We show that the results of such simulations exhibit excellent agreement with the standard PC1D one-dimensional photovoltaic simulation. Photonic and plasmonic attempts to enhance SC efficiency demand comprehensive electromagnetic calculations to be undertaken in order to acquire accurate carrier generation profiles in two and three-dimensional systems. Our model provides complete spectral and spatial information of typical optical and electronic behavior. Furthermore, our approach permits the detailed investigation of complex systems, including plasmonic SCs, which cannot be simulated using low-dimensional modeling tools. We present the results of numerical simulations of an optically thin plasmonic gallium arsenide SC and observe improved device performance arising from the application of plasmonic nanostructures, which agree well with previous experimental findings.

We report three-dimensional modelling of plasmonic solar cells in which electromagnetic simulation is directly linked to carrier transport calculations. To date, descriptions of plasmonic solar cells have only involved electromagnetic modelling without realistic assumptions about carrier transport, and we found that this leads to considerable discrepancies in behaviour particularly for devices based on materials with low carrier mobility. Enhanced light absorption and improved electronic response arising from plasmonic nanoparticle arrays on the solar cell surface are observed, in good agreement with previous experiments. The complete three-dimensional modelling provides a means to design plasmonic solar cells accurately with a thorough understanding of the plasmonic interaction with a photovoltaic device.

Silicon solar cells are the most established solar cell technology and are expected to dominate the market in the near future. As state-of-the-art silicon solar cells are approaching the Shockley–Queisser limit, stacking silicon solar cells with other photovoltaic materials to form multi-junction devices is an obvious pathway to further raise the efficiency. However, many challenges stand in the way of fully realizing the potential of silicon tandem solar cells because heterogeneously integrating silicon with other materials often degrades their qualities. Recently, above or near 30% silicon tandem solar cell has been demonstrated, showing the promise of achieving high-efficiency and low-cost solar cells via silicon tandem. This paper reviews the recent progress of integrating solar cell with other mainstream solar cell materials. The first part of this review focuses on the integration of silicon with III–V semiconductor solar cells, which is a long-researched topic since the emergence of III–V semiconductors. We will describe the main approaches—heteroepitaxy, wafer bonding and mechanical stacking—as well as other novel approaches. The second part introduces the integration of silicon with polycrystalline thin-film solar cells, mainly perovskites on silicon solar cells because of its rapid progress recently. We will also use an analytical model to compare the material qualities of different types of silicon tandem solar cells and project their practical efficiency limits.

Development of high-efficiency solar cell modules and new application fields are significant for the further development of photovoltaics (PVs) and the creation of new clean energy infrastructure based on PV. Notably, the development of PV-powered vehicle applications is desirable and very important for this end.According to the NEDO's Interim Report "PV-Powered Vehicle Strategy Committee," a new broader PV markets with more than 10 GW and 50 GW in 2030 and 2040, respectively, are expected to be established when PV-powered vehicles are developed. Cumulative PV capacity for PV-powered vehicles will be 50 GW and 0.4 TW in 2030 and 2040, respectively. This paper presents impacts on efficiency and cost for PV-powered vehicles. According to our survey, the use of more than 30% of high-efficiency PV enables 30 km per day driving without external charging and the society that the majority of the family cars run by the sunlight and without supplying gas. Thus, we are developing high-efficiency and low-cost solar cells and modules for automobile applications. In this paper, our analytical results for the efficiency potential of various solar cells for choosing candidates of high-efficiency solar cell modules for automobile applications. This paper also presents our recent approaches: demonstration car (Toyota Prius PHV) by using Sharp's high-efficiency III-V triple-junction solar cell modules with an output power of 860 W, static low concentrator InGaP/GaAs/InGaAs triple-junction solar cell module with efficiency of 32.84%, and so forth.