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Perovskite Solar Modules for the Residential Sector
Get PDFPerovskite solar cells have received tremendous attention within the solar research field in the past decade, due to their outstanding optoelectronic qualities (1,2) as well as the exciting prospect of low-cost processing, for instance, with roll-to-roll manufacturing. (3) After an astonishing first decade of development within the laboratory environment (from technology readiness level 1 to 4), now comes the time for the possible second phase of perovskite photovoltaics (PV), which will ultimately determine whether these model material candidates make their full transformation toward commercial modules. As the interest in perovskite PV expands toward new actors such as industrial companies, (4−6) policy-makers, (7,8) and news outlets, (9,10) the question still remains where exactly these new modules could benefit the solar industry most. With crystalline silicon (c-Si) PV already present on a very large scale at the utility level, we and others have shown that perovskite modules currently offer a relatively small window of opportunity for competition against this incumbent technology, (11,12) at least within the utility application scale and at the time of this writing. The picture is different when it comes to rapidly growing applications such as building-integrated photovoltaics (BIPV) (13) and for market segments where silicon PV remains more expensive, such as rooftop silicon PV for the commercial and industrial scales. (14) However, the following questions remain: When considering the residential PV sector, what are the specific technology requirements for perovskite modules to be cost-competitive with c-Si modules, and are these specifications indeed less stringent than those considered for utility scale PV? How do perovskite–silicon (per-Si) tandem modules compare in this regard? Finally, which cost reductions can we take into consideration for the development of these new technologies into the future, for both perovskite single-junction (SJ) modules and per-Si tandem modules
Complementary Surface-Enhanced Raman Scattering (SERS) and IR Absorption Spectroscopy (SEIRAS) with Nanorods-on-a-Mirror
Get PDFThe surface-enhanced counterparts of Raman scattering (SERS) and infrared (IR) absorption (SEIRAS) are commonly used to probe and identify nanoscale matter and small populations of molecules. The contrasting selection rules offer complementary vibrational information of bulk solids or solutions. In this study, a complementary surface-enhanced vibrational spectroscopy approach is presented to probe the vibrational signature of metal-bound molecular monolayers. Nanocavities are designed and produced with sharp and tunable visible (VIS) and mid-IR gap resonances by placing nanorods on a mirror that is coated with a thin dielectric spacer. Their VIS resonances are tuned to match a 1.61 eV (770 nm) resonant excitation for SERS, while their mid-IR resonances span the 1500–2800 cm−1 range (6.5–3.5 µm) in high resolution for SEIRAS, targeting CN bond vibrations at 2220 cm−1. Both the VIS and mid-IR gap modes support spatially overlapping and highly enhanced near-fields ensuring strong SERS and SEIRAS signals from the same monolayer molecular population. The differences in the vibrational information obtained with the two surface-enhanced spectroscopies when probing coupled molecular vibrations are highlighted and the advantages of using such a platform for investigating cavity-modified chemical reactions are discussed
Using picoliter droplet deposition to track clonal competition in adherent and organoid cancer cell cultures
Get PDFClonal growth and competition underlie processes of key relevance in etiology, progression and therapy response across all cancers. Here, we demonstrate a novel experimental approach, based on multi-color, fluorescent tagging of cell nuclei, in combination with picoliter droplet deposition, to study the clonal dynamics in two- and three-dimensional cell cultures. The method allows for the simultaneous visualization and analysis of multiple clones in individual multi-clonal colonies, providing a powerful tool for studying clonal dynamics and identifying clonal populations with distinct characteristics. Results of our experiments validate the utility of the method in studying clonal dynamics in vitro, and reveal differences in key aspects of clonal behavior of different cancer cell lines in monoculture conditions, as well as in co-cultures with stromal fibroblasts
Nanopatterned Back-Reflector with Engineered Near-Field/Far-Field Light Scattering for Enhanced Light Trapping in Silicon-Based Multijunction Solar Cells
Get PDFMultijunction solar cells provide a path to overcome the efficiency limits of standard silicon solar cells by harvesting a broader range of the solar spectrum more efficiently. However, Si-based multijunction architectures are hindered by incomplete harvesting in the near-infrared (near-IR) spectral range as Si subcells have weak absorption close to the band gap. Here, we introduce an integrated near-field/far-field light trapping scheme to enhance the efficiency of silicon-based multijunction solar cells in the near-IR range. To achieve this, we design a nanopatterned diffractive silver back-reflector featuring a scattering matrix that optimizes trapping of multiply scattered light into a range of diffraction angles. We minimize reflection to the zeroth order and parasitic plasmonic absorption in silver by engineering destructive interference in the patterned back-contact. Numerical and experimental assessment of the optimal design on the performance of single-junction Si TOPCon solar cells highlights an improved external quantum efficiency over a planar back-reflector (+1.52 mA/cm2). Nanopatterned metagrating back-reflectors are fabricated on GaInP/GaInAsP//Si two-terminal triple-junction solar cells via substrate conformal imprint lithography and characterized optically and electronically, demonstrating a power conversion efficiency improvement of +0.9%abs over the planar reference. Overall, our work demonstrates the potential of nanophotonic light trapping for enhancing the efficiency of silicon-based multijunction solar cells, paving the way for more efficient and sustainable solar energy technologies
Scalar potentials for light in a cavity
Get PDFThe nonequilibrium dynamics of light in a coherently driven nonlinear cavity resembles the equilibrium dynamics of a Brownian particle in a scalar potential. This resemblance has been known for decades, but the correspondence between the two systems has never been properly assessed. Here we demonstrate that this correspondence can be exact, be approximate, or break down, depending on the driving conditions. For vanishing nonlinearity and on-resonance driving, the correspondence is exact: The cavity dissipation and driving amplitude define a scalar potential, and light follows the equilibrium Boltzmann distribution with an effective temperature defined by the noise variance and cavity dissipation. The scalar potential pertaining to linear on-resonance dynamics fails dramatically in nonlinear and/or off-resonance regimes. However, we introduce a distinct scalar potential enabling an effective equilibrium description of light. Our potential gives a reasonably accurate description in limited nonlinear regimes of bistability, but fails deep in the bistability where nonconservative forces dominate the dynamics. Consequently, the correspondence to Brownian motion in a scalar potential breaks down. This breakdown is accompanied by a qualitative change in the spectrum of small intracavity field fluctuations, reminiscent of an exceptional point of a non-Hermitian Hamiltonian. Our results lay the foundations for an effective thermodynamic description of coherently driven cavities, and suggest that fundamental results for overdamped Langevin dynamics can help to assess the energetics and information processing of resonant optical technologies
High-speed imaging of giant unilamellar vesicle production in cDICE
Get PDFGiant unilamellar vesicles (GUVs) are cell-sized containers that are commonly used as three-dimensional model membranes in biophysics, as in vitro model systems in synthetic biology, and even as cargo carriers in various other research fields. Despite their ubiquitous use, there is still no one-size-fits-all GUV production method. Over the years, numerous methods have been developed, attempting to meet the demanding requirements of robustness, reliability, and high yield while simultaneously achieving robust encapsulation. Double emulsion-based methods are often praised for their apparent simplicity and good yields; hence, methods like continuous droplet interface crossing encapsulation (cDICE) that make use of this principle, have gained popularity in recent years. In cDICE, aqueous droplets that originate from a capillary orifice are continuously forced through an oil-water interface by centrifugal force, thereby forming a lipid bilayer and thus GUVs. Although cDICE and related methods are frequently used in the field, the complexity of the underlying principles and fluid dynamics has not been considered previously, and how exactly the GUVs are being formed remains unknown. To elucidate the process of GUV formation in cDICE, we have developed a high-speed microscopy setup that allows us to visualize GUV formation in real time. We focused on the capillary orifice, where initial droplet formation occurs, and on the oil-water interface, where droplets are converted into GUVs. Our experiments reveal a complex droplet formation process at the capillary orifice and suboptimal droplet transfer through the water-oil interface, which we explain using fluid dynamics and theoretical modeling. Our results are a first step towards explaining the widely observed variation in encapsulation efficiency and size polydispersity in cDICE. Ultimately, these results will contribute to a better understanding of GUV formation processes in cDICE and in extension, in double emulsion-based methods in general
Direct environmental lead detection by photoluminescent perovskite formation with nanogram sensitivity
Get PDFAlthough the global ban on leaded gasoline has markedly reduced lead poisoning, many other environmental sources of lead exposure, such as paint, pipes, mines, and recycling sites remain. Existing methods to identify these sources are either costly or unreliable. We report here a new, sensitive, and inexpensive lead detection method that relies on the formation of a perovskite semiconductor. The method only requires spraying the material of interest with methylammonium bromide and observing whether photoluminesence occurs under UV light to indicate the presence of lead. The method detects as little as 1.0 ng/mm2 of lead by the naked eye and 50 pg/mm2 using a digital photo camera. We exposed more than 50 different materials to our reagent and found no false negatives or false positives. The method readily detects lead in soil, paint, glazing, cables, glass, plastics, and dust and could be widely used for testing the environment and preventing lead poisoning
Trade-offs between cost and information in cellular prediction
Get PDFLiving cells can leverage correlations in environmental fluctuations to predict the future environment and mount a response ahead of time. To this end, cells need to encode the past signal into the output of the intracellular network from which the future input is predicted. Yet, storing information is costly while not all features of the past signal are equally informative on the future input signal. Here, we show for two classes of input signals that cellular networks can reach the fundamental bound on the predictive information as set by the information extracted from the past signal: Push–pull networks can reach this information bound for Markovian signals, while networks that take a temporal derivative can reach the bound for predicting the future derivative of non-Markovian signals. However, the bits of past information that are most informative about the future signal are also prohibitively costly. As a result, the optimal system that maximizes the predictive information for a given resource cost is, in general, not at the information bound. Applying our theory to the chemotaxis network of Escherichia coli reveals that its adaptive kernel is optimal for predicting future concentration changes over a broad range of background concentrations, and that the system has been tailored to predicting these changes in shallow gradients
A techno-economic perspective on rigid and flexible perovskite solar modules
No full textPerovskite solar cells have shown considerable developments in the last decade, and commercial applications are drawing closer. In this article, we present a techno-economic study of perovskite PV technologies. We compare published data on manufacturing costs of single-junction perovskite modules and find that they are dependent on the module design (rigid or flexible) and vary from 10 to almost 100 € per m2. We calculate the LCOE as a function of module efficiency and stability for a set of four module cost scenarios at 12.5, 25, 50, and 100 € per m2. The resulting LCOE varies from 4.3 to 25.5 ct kW−1 h−1 and shows low potential for immediate competition with crystalline silicon PV in the utility sector. Perovskite PV's competitive advantage lies in both lighter and less rigid modules, and in the development of tandem modules together with silicon. We hence extend the LCOE equation to highlight the benefit of producing flexible low-weight modules by roll-to-roll manufacturing, and modify the LCOE maps to showcase the benefits of tandem modules. Based on learning curve analyses applied to the CAPEX of single-junction and tandem modules, we develop three scenarios for the evolution of the LCOE of perovskite modules from 2025 to 2050. Under the optimistic scenarios, we find that the LCOE could reduce to 2.8 ct kW−1 h−1 by 2050
Observing Aqueous Proton-Uptake Reactions Triggered by Light
Get PDFProton-transfer reactions in water are essential to chemistry and biology. Earlier studies reported on aqueous proton-transfer mechanisms by observing light-triggered reactions of strong (photo)acids and weak bases. Similar studies on strong (photo)base-weak acid reactions would also be of interest because earlier theoretical works found evidence for mechanistic differences between aqueous H+ and OH- transfer. In this work, we study the reaction of actinoquinol, a water-soluble strong photobase, with the water solvent and the weak acid succinimide. We find that in aqueous solutions containing succinimide, the proton-transfer reaction proceeds via two parallel and competing reaction channels. In the first channel, actinoquinol extracts a proton from water, after which the newly generated hydroxide ion is scavenged by succinimide. In the second channel, succinimide forms a hydrogen-bonded complex with actinoquinol and the proton is transferred directly. Interestingly, we do not observe proton conduction in water-separated actinoquinol-succinimide complexes, which makes the newly studied strong base-weak acid reaction essentially different from previously studied strong acid-weak base reactions